WA Fact Sheet South Wastewater Treatment Plant FINAL by MikeJenny

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									               FACT SHEET FOR NPDES PERMIT WA-002958-1
          KING COUNTY SOUTH WASTEWATER TREATMENT PLANT
                                      September 30, 2009

PURPOSE of this Fact Sheet

This fact sheet explains and documents the decisions Ecology made in drafting the proposed
National Pollutant Discharge Elimination System (NPDES) permit for King County’s South
Wastewater Treatment Plant (South WWTP).

This fact sheet complies with Section 173-220-060 of the Washington Administrative Code
(WAC), which requires Ecology to prepare a draft permit and accompanying fact sheet for
public evaluation before issuing an NPDES permit.

Ecology makes the draft permit and fact sheet available for public review and comment at least
thirty (30) days before issuing the final permit. Copies of the fact sheet and draft permit for King
County’s South WWTP NPDES permit WA-002958-1, were available for public review and
comment from July 31, 2009, until September 18, 2009. For more details on preparing and filing
comments about these documents, please see Appendix A—Public Involvement Information.

King County (County) reviewed the draft permit and fact sheet for factual accuracy. Ecology
corrected any errors or omissions regarding the facility’s location, history, discharges, or
receiving water.

After the public comment period closed, Ecology included all comments received and provided
responses to them. Ecology included the summary and responses to comments in this fact sheet
as Appendix J—Response to Comments, and published it when issuing the final NPDES
permit. Ecology will not revise the rest of the fact sheet, but the full document will become part
of the legal history contained in the facility’s permit file.

Mark Henley, P.E., municipal permit manager, prepared the permit and this fact sheet.
Fact Sheet for NPDES Permit WA-002958-1                                                                              Page 2 of 101
King County South Wastewater Treatment Plant


                                                 TABLE OF CONTENTS

I.      EXECUTIVE SUMMARY .................................................................................................5 
        Dilution Factors ...................................................................................................................5 
        Effluent Limits .....................................................................................................................5 
        Sediment Monitoring ...........................................................................................................6 
        Source Tracking ...................................................................................................................6 
        Priority Pollutant Testing .....................................................................................................7
        Receiving Water Characterization……………………………………………………….. 7
        Nitrogen Reduction Study....................................................................................................7
        INTRODUCTION………………………………………………………………………... 8

II.     BACKGROUND INFORMATION ....................................................................................9 
            Table 1.  General Facility Information ...................................................................9 
            Figure 1.  Vicinity Map - King County South WWTP ..........................................9 
            Figure 2.  Aerial Photograph - King County South WWTP ................................10 
        A.  Facility Description ................................................................................................10 
            History……………………....................................................................................10 
            Collection System Status .......................................................................................11 
            Table 2.  Agencies Tributary to South WWTP ....................................................11 
            Figure 3.  Average Monthly Flow and Total Monthly Rainfall ...........................12 
            Figure 4.  Average Monthly Influent BOD and TSS Mass Loadings ..................13 
            Table 3.  Current and Projected (2009-2014) Influent Flow and Loadings .........13 
            Treatment Processes...............................................................................................14 
            Figure 5.  South WWTP – Simplified Process Flow Schematic ..........................14 
            Table 4.  South WWTP Staffing ..........................................................................17 
            Discharge Outfalls .................................................................................................17 
            Residual Solids.......................................................................................................19 
            Reuse - Secondary Treated Effluent ......................................................................19 
        B.  Permit Status ..........................................................................................................19 
            Table 5.  Previous Permit’s Effluent Limits .........................................................20 
        C.  Summary of Compliance With Previous Permit Issued on September 30, 2004 ..20 
            Table 6.  Compliance With Effluent Permit Limits .............................................21 
        D.  Wastewater Effluent, Whole Effluent Toxicity, and Sediment
            Characterizations....................................................................................................21 
            Table 7.  Wastewater Effluent Characterization ..................................................22 
            Whole Effluent Toxicity Testing ...........................................................................22 
            Table 8.  Detected Chemicals Above or Approaching SQS Criteria ...................24 
            Figure 6.  Sediment Sampling Locations from 1994-2001 .................................24 
        E.  SEPA Compliance .................................................................................................25 

III.    PROPOSED PERMIT LIMITS .........................................................................................25 
        A.   Design Criteria .......................................................................................................25
             Table 9. Design Standards for King County South WWTP…………………... 26
        B.   Technology-Based Effluent Limits ........................................................................26 
             Table 10.  Technology-Based Limits. ..................................................................26 
Fact Sheet for NPDES Permit WA-002958-1                                                                               Page 3 of 101
King County South Wastewater Treatment Plant
        C.        Surface Water Quality-Based Effluent Limits .......................................................27 
                  Numerical Criteria for the Protection of Aquatic Life and Recreation ..................27 
                  Numerical Criteria for the Protection of Human Health ........................................27 
                  Narrative Criteria ...................................................................................................27 
                  Antidegradation......................................................................................................28 
                  Mixing Zones……………………………………………………………............. 29 
        D.        Designated Uses and Surface Water Quality Criteria ............................................33 
                  Table 11.  Aquatic Life Uses and Associated Criteria .........................................34 
                  Table 12.  Recreational Uses ................................................................................34 
                  Table 13.  Aquatic Life Uses & Associated Criteria ............................................35 
                  Table 14.  Recreational Uses and Associated Criteria .........................................35 
        E.        Evaluation of Surface Water Quality-Based Effluent Limits for Numeric
                  Criteria ...................................................................................................................35 
                  Puget Sound Outfall No. 001 .................................................................................35 
                  Chronic Mixing Zone (Outfall 001) .......................................................................36 
                  Acute Mixing Zone (Outfall 001) ..........................................................................36 
                  Dilution Factors .....................................................................................................36 
                  Table 15.  Comparison of Dilution Ratios ...........................................................36 
                  Table 16.  Dilution Ratio for Outfall No. 001 ......................................................37 
                  Table 17.  Dilution Ratio - Green River Outfall No. 002.....................................41 
        F.        Whole Effluent Toxicity ........................................................................................42 
        G.        Human Health ........................................................................................................43 
        H.        Sediment Quality ...................................................................................................44 
        I.        Ground Water Quality Limits ................................................................................45 
        J.        Comparison of Effluent Limits With the Previous Permit Issued on
                  September 30, 2004 ...............................................................................................45 
                  Table 18.  Comparison of Effluent Limits ...........................................................45 

IV.     MONITORING REQUIREMENTS ..................................................................................46 
        A.   Lab Accreditation...................................................................................................46 

V.      OTHER PERMIT CONDITIONS .....................................................................................47 
        A.   Reporting and Record Keeping ..............................................................................47 
        B.   Prevention of Facility Overloading ........................................................................47 
        C.   Operation and Maintenance (O&M) ......................................................................47 
        D.   Pretreatment ...........................................................................................................47 
             Duty to Enforce Discharge Prohibitions ................................................................47 
        E.   Solid Waste Control ...............................................................................................48 
        F.   Spill Plan ................................................................................................................48 
        G.   Outfall Evaluation ..................................................................................................48 
        H.   General Conditions ................................................................................................49 

VI.     PERMIT ISSUANCE PROCEDURES .............................................................................49 
        A.   Permit Modifications .............................................................................................49 
        B.   Proposed Permit Issuance ......................................................................................49 

VII.    REFERENCES FOR TEXT AND APPENDICES............................................................50
Fact Sheet for NPDES Permit WA-002958-1                                                                           Page 4 of 101
King County South Wastewater Treatment Plant



APPENDIX A—PUBLIC INVOLVEMENT INFORMATION ...................................................51

APPENDIX B—GLOSSARY .......................................................................................................52 

APPENDIX C—SOUTH WWTP APPLICATION PRIORITY POLLUTANT DATA
     SUMMARY .......................................................................................................................56 

APPENDIX D—SOUTH WWTP DISCHARGE MONITORING REPORT SUMMARY
     TABLES ............................................................................................................................60 

APPENDIX E—SOUTH WWTP DISCHARGE MONITORING REPORT GRAPHS ..............63 

APPENDIX F—OUTFALL DIAGRAMS ....................................................................................69 

APPENDIX G—WHOLE EFFLUENT TOXICITY (WET) TESTING RESULTS .....................73 

APPENDIX H—TECHNICAL CALCULATIONS ......................................................................74 
     Table H-1:  South WWTP – Water Quality Criteria for Detected Pollutants ...............75 
     Table H-2:  South WWTP – Ammonia Calculation Spreadsheet .................................76 
     Table H-3:  South WWTP – Reasonable Potential to Exceed the Water Quality
                  Standards ....................................................................................................77 
     Table H-4:  South WWTP – Chlorine Limit to Meet Water Quality Limit ..................78 
     Table H-5:  South WWTP – Reasonable Potential to Exceed Human Health
                  Criteria .......................................................................................................79 
     Table H-6:  South WWTP – Ambient Monitoring Data Summary ...............................81 
     Table H-7:  South WWTP – Dilution Assessment for Temperature .............................82 
     Table H-8:  South WWTP – Dilution Assessment for Fecal Coliform Bacteria ..........83 
     Table H-9:  South WWTP – Assessment for Impacts to Dissolved Oxygen ................84 
     Table H-10:  South WWTP – Assessment for pH...........................................................85 

APPENDIX I—INDUSTRIAL DISCHARGERS TO COUNTY’S SOUTH WWTP ..................86 

APPENDIX J—RESPONSE TO COMMENTS............................................................................87 
     Fact Sheet for NPDES Permit WA-002958-1                                            Page 5 of 101
     King County South Wastewater Treatment Plant

I.   EXECUTIVE SUMMARY

     Washington State rules require that the owner of a municipal wastewater treatment plant
     (WWTP) obtain a National Pollutant Discharge Elimination System (NPDES) permit prior to
     discharging wastewater to State waters. Statutes, rules, and guidance are used to establish the
     discharge limitation for pollutants and other permit requirements. Most NPDES permits are
     effective for five years and may be administratively extended.

     King County’s Wastewater Treatment Division owns and operates the South WWTP. King
     County applied for the renewal of their NPDES permit for the South WWTP on March 30, 2009.
     Ecology prepared a draft permit and accompanying fact sheet and made it available for public
     comment on July 31, 2009.

     The information below describes major changes from the previous permit (October 1, 2004 to
     September 30, 2009) to the proposed, renewed permit (November 1, 2009 to September 30,
     2014).

     Dilution Factors

     Ecology provided a thorough review of the County’s data, dilution factors, and modeling in June
     2009. Ecology verified that the County used conservative assumptions and provided rigorous
     modeling to obtain dilution factors. The dilution ratios predicted from the current modeling
     effort are substantially different (lower) from those predicted in the previous analysis, and are
     described in the table below. Ecology revised the dilution factors because the County 1) used
     new and improved computer models, 2) collected additional density profile data; and 3) updated
     plant flow rates. Ecology considers the dilution factors in the proposed permit more up-to-date
     and representative than the factors in the previous permit. Note that all of the dilution factors
     decreased (more restrictive) from the previous permit.
     Comparison of Dilution Ratio

           Outfall         Chronic   Zone of Acute    Proposed    Current     Proposed       Current
                         Mixing Zone    Criteria       Chronic    Chronic       Acute         Acute
                           Radius     Exceedance       Dilution   Dilution     Dilution      Dilution
                           (feet) a     (feet) a        Ratio      Ratio        Ratio         Ratio
     South WWTP               825              82.5     225:1      429:1        186:1         233:1
     a
         – as measured horizontally from each port

     Effluent Limits

     The following table compares the effluent limits from the previous permit to this final permit.
     The effluent limits for the South Wastewater Treatment Plant are unchanged from the previous
     permit because:

     1.      Washington State’s rule requiring secondary treatment limits for municipal WWTPs has not
             changed.
Fact Sheet for NPDES Permit WA-002958-1                                                       Page 6 of 101
King County South Wastewater Treatment Plant
2.   South WWTP did not violate any of its effluent parameters in the last 5 years.

3.   The reasonable potential analysis did not indicate that any priority pollutant or toxic
     pollutant in the South WWTP’s discharge had a reasonable potential to violate the water
     quality standards.

4.   The whole effluent toxicity (WET) testing on fish indicated that the South WWTP’s
     discharge is unlikely to cause fish toxicity problems in Puget Sound.

For more specific information, please refer to the additional fact sheet information that follows.
Comparison of Effluent Limits (South WWTP – Outfall 001)
        Parameter          Basis of Limit        Previous Effluent Limits:          Proposed Effluent Limits:
                                                       Outfall # 001                        Outfall # 001
                                                 Average          Average          Average             Average
                                                 Monthly           Weekly          Monthly             Weekly
 Biochemical Oxygen        Technology        30 mg/L,           45 mg/L,        30 mg/L,          45 mg/L,
 Demand (5-day)                              36,000 lbs/day, 54,000 lbs/day     36,000 lbs/day, 54,000 lbs/day
                                             85% removal of                     85% removal
                                             influent BOD                       of influent BOD
 Total Suspended Solids    Technology        30 mg/L,           45 mg/L,        30 mg/L,          45 mg/L,
                                             36,000 lbs/day, 54,000 lbs/day     36,000 lbs/day, 54,000 lbs/day
                                             85% removal of                     85% removal
                                             influent BOD                       of influent BOD
 Fecal Coliform Bacteria   Technology        200/100 mL         400/100 mL      200/100 mL        400/100 mL
 pH                        Technology       Daily Minimum is equal to or       Daily Minimum is equal to or
                                            greater than 6.0 and the daily     greater than 6.0 and the daily
                                            maximum is less than or equal to   maximum is less than or equal to
                                            9.0                                9.0
        Parameter          Basis of Limit      Previous Effluent Limits:           Proposed Effluent Limits:
                                                    Outfall # 001                       Outfall # 001
                                               Average          Maximum           Average           Maximum
                                               Monthly           Daily            Monthly            Daily
 Total Residual Chlorine   Guidance/        0.5 mg/L          0.75 mg/L        0.5 mg/L         0.75 mg/L
                           Technology-
                           Based


Sediment Monitoring

The proposed permit requires King County to test more extensively for sediment toxicity in the
vicinity of the South WWTP outfall than the previous permit. The proposed permit includes
bioassays to be performed, if the chemical concentrations are near or above the numeric chemical
criteria in the Sediment Management Standards.

Source Tracking

In order to more fully characterize industrial discharges into the County’s conveyance system
and ultimately to South WWTP, the County must conduct pollutant analysis for metals, cyanide,
phenols, volatile compounds, acid compounds, and base/neutral compounds of at least one
industry in each of the metal-finishing/electroplating, centralized waste treatment, plastic
products, coil coating, and food processing categories.
Fact Sheet for NPDES Permit WA-002958-1                                         Page 7 of 101
King County South Wastewater Treatment Plant
Priority Pollutant Testing

The previous permit included priority pollutant sampling once per year for the South WWTP
effluent. This permit includes priority pollutant sampling twice per year.

Receiving Water Characterization

In the vicinity of the South WWTP outfall, the Permittee must provide data via ambient monitoring
stations or collect receiving water information via field sampling necessary to determine if the
effluent has a reasonable potential to cause a violation of the water quality standards.

Nitrogen Reduction Study

Ecology has two studies underway to inform on the impacts of nutrient-laden discharges to Puget
Sound. Ecology expects to complete the South Sound Dissolved Oxygen Study along with the
Puget Sound Hydrodynamic Modeling by December 2010.

Upon completion of both the South Puget Sound Dissolved Oxygen Study and Hydrodynamic
Modeling, Ecology will determine whether the discharge from King County’s South WWTP is
significantly and quantifiably impacting dissolved oxygen levels in South Puget Sound. If
Ecology concludes that there is a significant and quantifiable adverse impact from the South
WWTP discharge on dissolved oxygen in South Puget Sound, then Ecology will require King
County to submit a Nitrogen Reduction Study to evaluate feasible alternatives to reduce nitrogen
contributions from the South WWTP discharge.
Fact Sheet for NPDES Permit WA-002958-1                                         Page 8 of 101
King County South Wastewater Treatment Plant
INTRODUCTION
The Federal Clean Water Act (FCWA, 1972, and later amendments in 1977, 1981, and 1987)
established water quality goals for the navigable (surface) waters of the United States. One
mechanism for achieving the goals of the Clean Water Act is the National Pollutant Discharge
Elimination System (NPDES), administered by the federal Environmental Protection Agency
(EPA). The EPA authorized the State of Washington to manage the NPDES permit program in
our state. Our state legislature accepted the delegation and assigned the power and duty for
conducting NPDES permitting and enforcement to Ecology. The legislature defined Ecology's
authority and obligations for the wastewater discharge permit program in 90.48 RCW (Revised
Code of Washington).

The following regulations apply to municipal NPDES permits:

   •   Procedures Ecology follows for issuing NPDES permits (Chapter 173-220 WAC)

   •   Technical criteria for discharges from municipal wastewater treatment facilities (Chapter
       173-221 WAC)

   •   Water quality criteria for surface waters (Chapter 173-201A WAC) and for ground waters
       (Chapter 173-200 WAC)

   •   Sediment management standards (Chapter 173-204 WAC)

   •   Submission of Plans and Reports for Construction of Wastewater Facilities (Chapter
       173-240 WAC)

These rules require any treatment facility operator to obtain an NPDES permit before discharging
wastewater to state waters. They also help define the basis for limits on each discharge and for
requirements imposed by the permit.

Under the NPDES permit program and in response to a complete and accepted permit application,
Ecology must prepare a draft permit and accompanying fact sheet, and make them available for
public review before final issuance. Ecology must also publish an announcement (public notice)
telling people where they can read the draft permit, and where to send their comments, during a
period of thirty days (WAC 173-220-050). (See Appendix A—Public Involvement Information
for more detail about the public notice and comment procedures). After the public comment period
ends, Ecology may make changes to the draft NPDES permit. Ecology will summarize the
responses to comments and any changes to the permit in Appendix J.
      Fact Sheet for NPDES Permit WA-002958-1                                        Page 9 of 101
      King County South Wastewater Treatment Plant

II.   BACKGROUND INFORMATION
          Table 1.    General Facility Information

       Applicant:                            King County Department of Natural Resources and Parks
                                             Wastewater Treatment Division
                                             201 S. Jackson Street, MS KSC-NR-0500
                                             Seattle, WA 98104-3855
       Facility Name and Address:            King County South Wastewater Treatment Plant
                                             1200 Monster Road SW
                                             Renton, WA 98057
       Type of Treatment:                    Secondary Treatment, Activated Sludge
       Discharge Location:                   Puget Sound     North Diffuser      South Diffuser
                                             Latitude:       47° 36' 10" N       47° 35' 59" N
                                             Longitude:      122° 25' 44.4" W 122° 25' 44.5" W
                                             Emergency/Maintenance (Green River)
                                             Latitude:   47° 28' 03" N
                                             Longitude: 122° 14' 39" W




          Figure 1.    Vicinity Map - King County South Wastewater Treatment Plant
Fact Sheet for NPDES Permit WA-002958-1                                        Page 10 of 101
King County South Wastewater Treatment Plant




    Figure 2.    Aerial Photograph - King County South Wastewater Treatment Plant


A. Facility Description

    History
    In 1958, voters in Seattle and King County created Metro, an agency charged with creating
    a regional wastewater conveyance and treatment system. The South Wastewater Treatment
    Plant (South WWTP) located in Renton is often referred to by County staff as the South
    Treatment Plant (STP). Metro completed construction of the plant in 1965. The original
    plant had the capacity to treat 24 million gallons per day (MGD) of wastewater to secondary
    treatment levels using an activated sludge biological process. The third, and latest,
    expansion of the plant began in 1991 and was considered complete in 2000-2001. This last
    upgrade brings the plant design capacity to 144 MGD maximum month flow (MMF). In
    2003, the County replaced the 90-ton railcar chlorine system with an interim sodium
    hypochlorite (12.5% NaOCl solution) disinfection facility. The City of Renton required the
    County to remove gaseous chlorine from the South WWTP site. The County is currently
    constructing a permanent sodium hypochlorite disinfection facility and plans completion in
    2010. In 2005, the solids dewatering facility was expanded by replacing eight belt filter
    presses (50-gpm each) with three high-solids centrifuges (350-gpm capacity each).
    The South Wastewater Treatment Plant is designated as an EPA major facility due to the
    magnitude of its daily discharge volume.
Fact Sheet for NPDES Permit WA-002958-1                                          Page 11 of 101
King County South Wastewater Treatment Plant
    Collection System Status
    The South Wastewater Treatment Plant serves an area of 152 square miles. King County owns
    and operates the major sewer interceptors and pump stations that carry the wastewater to the
    treatment plant. The component agencies (tabulated below) individually own, operate, and
    maintain the pipelines and other conveyance facilities that carry wastewater to the County’s
    interceptors. Wastewater is conveyed to the treatment plant via three interceptors, the Tukwila
    Interceptor, the South Interceptor, and the Eastside Interceptor and by the 26 pump stations in the
    system. The County monitors and controls the collection system using a SCADA (Supervisory
    Control and Data Acquisition) system located at the South Wastewater Treatment Plant.
    The South Wastewater Treatment Plant serves 25 jurisdictions and utility districts as noted in
    the County’s 2009 NPDES permit application and as listed below.
    Table 2.    Agencies Tributary to South WWTP
                                              Agencies
       Cities                      Sewer/Utility Districts                       Other
Algona            Cedar River Water And Sewer District                 Muckleshoot Indian Tribe
Auburn            Coal Creek Utility District                          Shorewood Apartments
Bellevue          Lakehaven Utility District
Black Diamond     Northeast Sammamish Sewer And Water District
Issaquah          Northshore Utility District
Kent              Sammamish Plateau Water And Sewer District
Kirkland          Seattle Public Utilities
Mercer Island     Skyway Water And Sewer District
Pacific           Soos Creek Water And Sewer District
Redmond           Valley View Sewer District
Renton
Tukwila

    CSO Status
    All component agencies that provide flow to the South Wastewater Treatment Plant are separated
    sanitary systems with the exception of a small portion (approximately 4%) of the Seattle system
    that is a combined system. The South Wastewater Treatment Plant will continue to treat a
    portion of the flow from the Henderson CSO and Martin Luther King (MLK) diversion structure
    combined systems during the term of this permit. During heavy rain events, King County’s West
    Point Treatment Plant treats some of the flow. The MLK/Henderson/Norfolk project provides a
    tunnel for the storage and primary sedimentation of flows from Henderson, Martin Luther King,
    and Norfolk CSOs. During small rain events, the tunnel stores CSO flows for transfer to the
    South Wastewater Treatment Plant for secondary treatment. During the largest storms and when
    the tunnel fills, any flows that exceed the capacity of the tunnel storage will be treated and
    disinfected and discharged through the existing Norfolk CSO (which is included in King
    County’s West Point Treatment Plant Permit).

    Flow Blending
    During the previous permit cycle, Ecology authorized King County’s South Wastewater
    Treatment Plant to utilize flow blending to manage peak flow events. The South WWTP had
    twelve blending events between October 2004 and February 2009. In all of the twelve blending
Fact Sheet for NPDES Permit WA-002958-1                                                         Page 12 of 101
King County South Wastewater Treatment Plant
    events, the County initiated blending only after solids started to wash out of the secondary
    process or when secondary flows were notably above 190-200 MGD. According to King
    County staff, blending proved successful at reducing the washout of secondary solids from the
    secondary clarifiers. There is no formally-adopted policy for flow blending in federal or state
    regulations at the writing of this permit. This permit does not authorize the use of flow
    blending, but rather relies on the bypass provision in Special Condition S5 of the permit to
    address any bypassing of treatment units.

    Inflow and Infiltration
    The King County Council has approved the Regional Infiltration/Inflow (I/I) Control Program
    as part of its Regional Wastewater Services Plan (RWSP). It is the first comprehensive
    investigation of I/I in the local agency service areas and is based on a cooperative partnership
    between King County and the 34 local agencies serving the Seattle Metropolitan area.

    Flow and Waste Load
    King County submitted, with the application for permit renewal and as required by the
    previous permit, a Flow and Waste Load Assessment. The graphs below show the hydraulic
    and organic loading to the South Wastewater Treatment Plant from October 2004 through
    December 2008 as based on data submitted in the DMRs.

                                                  South Plant Flow and Rain
                                                         2004 - 2008
                  240                                                                           40

                  220                                                                           36
                                     Flow, month avg
                  200                Flow, max-day                                              32
                                     Rain, month total




                                                                                                     Rainfall, inches (month total)
                  180                                                                           28

                  160                                                                           24
      Flow, MGD




                  140                                                                           20

                  120                                                                           16

                  100                                                                           12

                   80                                                                           8

                   60                                                                           4

                   40                                                                           0
                        Jan-04




                                         Jan-05




                                                         Jan-06




                                                                    Jan-07




                                                                              Jan-08




                                                                                       Jan-09




    Figure 3.                    Average Monthly Flow and Total Monthly Rainfall
    Per Figure 3, the highest average monthly flow for the time period October 2004 – December
    2008 was 133 MGD in January 2006. It was the result of the second wettest January on record
    (11.65-inches) which followed a very wet second half of December 2005. The 133 MGD
    monthly flow is the highest monthly flow ever recorded at South WWTP. In fact, the 30-day
    running average reached 138 MGD (on January 22, 2006). This 30-day running average is only
    6-mgd short of South WWTP’s maximum monthly flow capacity of 144-mgd. South WWTP met
    all of its effluent limits in January 2006 in spite of the heavy rainfall.
Fact Sheet for NPDES Permit WA-002958-1                                                               Page 13 of 101
King County South Wastewater Treatment Plant



                                                        South WWTP Influent Loads
                                                        Monthly Avg. BOD and TSS
                               225,000


                               200,000                             TSS
     Influent Loads, lbs/day




                                                                   BOD

                               175,000


                               150,000


                               125,000


                               100,000


                                75,000
                                         Jan-04      Jan-05       Jan-06       Jan-07        Jan-08         Jan-09


    Figure 4.                            Average Monthly Influent BOD and TSS Mass Loadings
    The maximum-month average TSS load during the last five years was 208,000 TSS lbs/day,
    which occurred in December 2004 and January 2005. The maximum month average TSS load
    of 208,000 lbs/day is 88% of the design maximum month loading. The maximum month
    BOD loading of 214,000 lbs/day occurred in January 2009, when the treatment plant received
    a large amount of deicer waste.

    Capacity Analysis
    Table 3 summarizes South WWTP’s design capacity and its current and projected flow and
    loadings through 2014. The County projected that all of the flows and loads between 2009 and
    2014 will be below South WWTP’s current design capacity assuming an average growth rate of
    1.5% to 1.8% per annum. Brightwater Wastewater Treatment Plant is scheduled to start operations
    in 2011, which will reduce South WWTP’s annual flow and loads by about 8%, and its wet weather
    flow and loads by 15%. Thus, the largest flows and loads over the next five years are projected to
    occur in 2010 and 2011 (i.e., just before the Brightwater Plant starts operation in 2011).

    Table 3.                             Current and Projected (2009-2014) Influent Flow and Loadings
     Parameter                                                    Design    2004-09     Projected     Projected
                                                                 Capacity     Max        2010-11        2014
     Flow Average Wet Weather, MGD                                 115        102          105           93
     Flow Max Month, MGD                                           144        133          138           121
     BOD Max Month Load, lbs/day                                 251,000    214,000      221,500       188,000
     TSS Max Month Load, lbs/day                                 235,000    208,000      215,100       182,000
Fact Sheet for NPDES Permit WA-002958-1                                Page 14 of 101
King County South Wastewater Treatment Plant
    Treatment Processes




    Figure 5.   South Wastewater Treatment Plant – Simplified Process Flow Schematic
Fact Sheet for NPDES Permit WA-002958-1                                           Page 15 of 101
King County South Wastewater Treatment Plant

    Headworks
    The raw sewage can flow through eight bar screens to remove rags and plastics. The
    screenings are conveyed down a trough to the grinder pumps. The ground screenings are
    cleaned and dewatered in preparation for disposal at a landfill. The raw (influent) pumps lift
    the wastewater 40 feet to a division channel providing for gravity flow through the
    remaining treatment processes. The wastewater flows through the aerated grit channels to
    allow for grit to settle out. The grit is pumped to the cyclones, discharged to the classifiers,
    and then into dumpsters.

    Primary Treatment
    The division channel splits flow between a north set of 4 primary clarifiers and south set of 8
    primary clarifiers. The north clarifiers use return flights and tipping troughs to capture and
    remove scum and grease. The south clarifiers use surface water spray to move scum and
    grease to a helical screw located at the upstream end of the tank; the return flights stay
    submerged on the south primaries. The primary clarifier effluent overflows via launders with
    submerged orifices. The launders saw-tooth weirs allow it to handle higher flows. Primary
    effluent flows by gravity to the aeration tanks. Primary sludge is continuously pumped from
    the bottom of the clarifiers to the dissolved air floatation tanks (DAFTs) for further treatment.

    Secondary Treatment
    Secondary treatment is accomplished using an activated sludge process. There are 4 aeration
    basins with fine bubble diffusers used for air distribution. The first part of each aeration
    basin is anaerobic when operating in the selector mode. Operators adjust the dissolved
    oxygen and sludge age to achieve a settable sludge. The aeration basin effluent flows from
    the aeration basins to the mixed liquor channel before distribution to the secondary clarifiers.
    There are 6 secondary clarifier pods each with 4 clarifiers for a total of 24 secondary
    clarifiers. Each pod has an effluent control center (ECC) where flow and turbidity are
    monitored. Pumps return the solids that settle out in the secondary clarifiers back to the
    aeration basins as return activated sludge (RAS) or pump them to solids handling as waste
    activated sludge (WAS).

    Disinfection and Effluent
    Beginning in June 2003, the facility converted to sodium hypochlorite for disinfection in
    order to eliminate handling of chlorine gas. Hypochlorite is added at several locations along
    the chlorine contact channels. The chlorinated effluent flows through the chlorine contact
    channel to the forebay tank located before the effluent pumps. The effluent pumps
    discharge the treated wastewater from the forebay to the plant’s Puget Sound outfall located
    12 miles away off a point of land north of Alki. The outfall terminates 10,000 feet off shore
    and is 625 feet deep (refer to Appendix F). Additionally, the effluent can flow by gravity to
    the outfall during low flow conditions.

    Water Reclamation
    This facility produces Class A water for reuse from a small portion of the plant’s flow. Plant
    operators use the chlorinated effluent water, referred to as C3 water, internally throughout the
    process in addition to feeding the water reclamation process. The Class A water treatment
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King County South Wastewater Treatment Plant
    process includes the required treatment steps of coagulation and filtration. The coagulant,
    currently a polyaluminum chlorhydrate product (PAC), is added to C3 water and mixed via an
    inline static mixer. The water then flows through Parkson DynaSand ® continuously back
    flushing sand filters. The filtered effluent is disinfected with hypochlorite through a series of
    three contact tanks.

    The plant designers set up the control logic for the reuse facility so that high turbidity (>3
    NTU) or low total residual chlorine detected in the water will automatically valve the
    off-specification water back to the treatment plant headworks. Only water meeting the Class A
    specifications flows into the 500,000-gallon reuse water storage tank. In addition to supplying
    the off-site customers by pipeline, the facility allows customers to load reuse water in truck
    mounted storage tanks for off-site use. Ecology permits water distribution from the
    reclamation facilities under a separate Reclaimed Water Permit.

    Solids Handling
    Solids from the primary clarifiers, WAS from the secondary clarifiers, and scum are pumped
    to the DAFTs. The DAFTs (4 older tanks, 2 new larger tanks) thicken the sludge. Inside
    these tanks, a mixture of sludge, polymer, and air form a thick layer of sludge that floats to the
    surface. A scraper arm controls the thickness of the floating sludge blanket and moves solids
    out of the DAFT to the Thickened Sludge Blending Tank. The water layer below the sludge
    blanket in the DAFT is pumped to the aeration tanks. The thin sludge layer that forms on the
    bottom of the DAFT is pumped to grit cyclones for degritting and sent back to the DAFTS for
    reprocessing.

    The contents of the thickened sludge blending tank are pumped on level control to 1 of 4
    anaerobic digesters. Operators collect daily process control samples of the digester sludge. The
    digested sludge is transferred to the 5th digester that serves as the blended sludge storage tank.
    Polymer is added as a coagulant to the sludge as it is pumped from the blended sludge storage
    tanks to the centrifuges. The centrifuges produce a biosolids product that is about 20-25%
    solids. The biosolids are hauled to beneficial reuse sites in Eastern Washington (agriculture
    applications), and Western Washington (forest applications and commercial composting).

    Odor Control
    Odor control consists of a couple different air scrubbing systems. Chemical scrubbers use
    caustic and hypochlorite solutions to control odors from the secondary treatment area, the
    primary treatment area, the sludge thickeners, and the dewatering area. Carbon scrubbers
    control odors in the sludge thickening and dewatering areas. In addition, the facility
    maintains a biofilter to control odors on the influent interceptor collection system.

    Emergency Backup Power
    The facility’s two independent power feeders to the plant provide redundancy. In addition, an
    emergency generator powers essential services, for example, lighting, alarms, security, etc.,
    although it is not sufficient to power the influent pumps or other plant processes. An 8-Mega
    Watt (MW) cogeneration facility is also located on-site. It consists of two 3.5-MW gas
    turbine generators and a 1-MW steam turbine generator. The cogeneration facility is fueled
    by pipeline natural gas or scrubbed digester gas produced at the South WWTP.
Fact Sheet for NPDES Permit WA-002958-1                                                Page 17 of 101
King County South Wastewater Treatment Plant

    Industrial and Commercial Users
    Ecology delegated King County the authority to run a Pretreatment Program. The South
    Wastewater Treatment Plant’s application for permit renewal lists a total of 65 industrial
    user discharges received by the treatment plant. There are 27 Significant Industrial Users
    (SIUs) and 38 Categorical Industrial Users (CIUs). Please refer to Appendix I for a list of
    the industrial users.

    Staffing
    Currently, the South WWTP employs 142 full-time employees (FTEs). The 142 FTEs
    provide service to not only the South WWTP and its off-site pump stations, but also to the
    treatment facilities for the City of Carnation, Vashon Island, and Buelah Cove and Park.
    The plant is staffed 24 hours per day with 12-hour shifts. Operators monitor and control
    critical plant operations from a central control room using a distributed control system
    (DCS). A supervisory control and data acquisition (SCADA) system is used to monitor
    off-site pump stations and facilities.

    Table 4.    South WWTP Staffing
     Work Group                    Est. FTEs    Responsibilities
     Shift Crew (4 shifts, 6 FTE   24           Operations
     per shift)
     Day Operations Crew           14           Assist with plant operations, training, special projects,
                                                and backfill for shift crews.
     Process Control Crew          11           Permit compliance issues, sampling, lab analysis,
                                                reporting, data handling, process setpoints, etc.
     Pump-run crew                 11           Operation of off-site pump stations and treatment
                                                systems.
     Maintenance Staff             36           Electricians and Instrument Technicians and
                                                Mechanics.
     Other                         37           Administration, Purchasing & Inventory, Building and
                                                Grounds Maintenance, Engineering & As-Builts,
                                                Technical Publications, etc.

    Future Construction Plans
    The facility is currently converting a temporary sodium hypochlorite system to a permanent
    system. The County is not planning any other major projects at the plant during the upcoming
    permit cycle.

    Discharge Outfalls

    Puget Sound Outfall 001
    Secondary treated and disinfected effluent is discharged from the facility via a 12-mile long
    8-foot diameter transfer line. The outfall consists of two pipelines, each extending over
    10,000 feet northwest into Elliot Bay from Duwamish Head. For nearshore protection, the
    initial portion is supported by legs and the remainder of the outfall rests along the seafloor in
    a shallow trench. An outfall junction structure is located at the end of the effluent transfer
Fact Sheet for NPDES Permit WA-002958-1                                          Page 18 of 101
King County South Wastewater Treatment Plant
    system (ETS) force main just west of Luna Park in West Seattle. The structure contains a
    64-inch diameter manifold connecting the 96-inch ETS to the two 64-inch outfall lines. The
    diffuser sections are on the final 500-ft of each leg. Each diffuser has 168-sweep radius
    diffuser ports, each 14 inches long and 4 inches in diameter. (This a total of 336 diffuser
    ports with a total diffuser opening of 336 * 0.087 ft2/port = 29.32 ft2.) The diffusers are
    staggered side-to-side every 3 feet. Each diffuser port is made of a copper-nickel alloy to
    inhibit bio-fouling. The diffusers are about 625 feet deep.
    The County inspected the marine outfall in 2004-2005. The extensive inspection concluded
    that all external components of the outfalls and associated structures appeared in good
    condition with no evidence of damage. However, the inspection report noted that many
    spans of the pipeline were unsupported, particularly in the steep sloping areas. Also, the
    report noted that sediments have buried significant portions of both pipelines since its
    installation. King County submitted video footage of the inspection along with the
    inspection report. Appendix F diagrams show the location of the marine outfall and the
    emergency outfall described in the next section.

    Green River Outfall (Maintenance & Emergency Purposes Only)
    The Green River outfall was the South WWTP’s sole discharge point prior to the
    construction of the marine outfall in 1987. The County increased the firm capacity (total
    capacity with one pump out of service) of the effluent transfer system (ETS), which carries
    flow to the marine outfall, to 325 MGD with the pumping system upgrade in 1999. With all
    pumps running, the predicted capacity is 340-360 MGD (depending on the tide). The
    proposed permit authorizes the treatment plant to discharge to the Green River during
    emergencies and for maintenance purposes only.

    An emergency discharge is an unplanned and unavoidable discharge which is necessary to
    prevent sewage overflows or damage to the plant. Emergency discharges may occur during
    a severe, heavy rain event when the flow exceeds the capacity of the ETS, or in the extreme
    event that the ETS loses significant capacity due to multiple equipment failures or power
    failure.

    Maintenance discharges are performed periodically to ensure that the outfall will function
    normally during an emergency event. During a maintenance discharge, the County uses a
    sufficient flow rate of disinfected and dechlorinated effluent to flush sediment from the
    diffuser ports. The proposed permit specifically authorizes discharges to the Green River
    for maintenance purposes.

    The diffuser is a 12-foot by 12-foot structure that is 44 feet long extending into the river.
    There are 8 discharge ports located on the downstream side of the diffuser. The top of each
    port is at the elevation of the river bottom.

    During the last permit cycle, no maintenance activities were performed on the Green River
    Outfall and therefore, no effluent was discharged to the Green River.
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King County South Wastewater Treatment Plant
    Residual Solids
    The treatment facilities remove solids during the treatment of the wastewater at the
    headworks (grit and screenings), and at the primary and secondary clarifiers, in addition to
    incidental solids (rags, scum, and other debris) removed as part of the routine maintenance
    of the equipment. Grit, rags, scum, and screenings are drained and disposed of as solid
    waste at a landfill. Primary and waste secondary sludge are co-thickened in the Dissolved
    Air Floatation Tanks. The thickened sludge is fed to the anaerobic, mesophilic digesters,
    which are maintained at 35-38 °C. The County blends and stores digested sludge in a tank
    followed by dewatering with centrifuges to produce biosolids. The biosolids are applied to
    forest and agriculture lands under a permit from the King County Health Department.
    The County periodically analyzes the biosolids for various chemical contaminants.
    Regulatory and compliance issues regarding biosolids are managed by the Department of
    Ecology’s Biosolids Program.

    Reuse - Secondary Treated Effluent
    A separate state Reclaimed Water Permit covers the existing water reclamation facility, the
    distribution of the Class A water it produces, and any future secondary effluent that is not
    returned to the ETS (effluent transfer system). The proposed NPDES permit regulates all
    direct discharges of treated secondary effluent that ultimately return the treated secondary
    effluent back to the ETS for discharge via the Puget Sound outfall.
    The proposed NPDES permit (Conditions S16) authorizes the County to distribute effluent
    from the ETS to Boeing for a specifically-identified use and allows it to distribute effluent
    for similar uses provided it receives written approval from both Ecology and the Department
    of Health. Following use the effluent discharges back to the ETS. Departmental approval is
    required for each application of direct reuse to ensure that such use does not cause a
    violation of the state water quality standards. The intent of the NPDES permit is to allow
    the Permittee flexibility to provide noncontact reuse water to customers with sufficient
    safeguards to ensure that the water quality standards are not violated.
    At the time of the writing of the permit, King County had one customer using treated
    secondary effluent in this manner. The Boeing Company uses secondary treated effluent in
    a closed-loop chiller system primarily during the summer months at the Boeing Training
    Center located in Renton, Washington. King County is permitted to enlist other customers
    located along the ETS corridor for noncontact use of the secondary treated effluent with
    return to the ETS for discharge at the Puget Sound Outfall.

B. Permit Status
    Ecology issued the previous permit for this facility on September 30, 2004. The previous
    permit placed effluent limits on 5-day Biochemical Oxygen Demand (BOD5), Total
    Suspended Solids (TSS), pH, Fecal Coliform Bacteria, and Total Residual Chlorine.
    King County submitted an application for permit renewal on March 31, 2009. Ecology
    accepted it as complete on April 14, 2009.
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King County South Wastewater Treatment Plant
    The effluent limits in the previous permit are as follows.

           Table 5. Previous Permit’s Effluent Limits
                                 EFFLUENT LIMITS a: OUTFALL # 1
                    Parameter                   Average Monthly              Average Weekly
    Biochemical Oxygen Demand b (BOD5)      30 mg/L, 36,000 lb/day       45 mg/L, 54,000 lb/day
                                            85% minimum removal
    Total Suspended Solids b                30 mg/L, 36,000 lb/day       45 mg/L, 54,000 lb/day
                                            85% minimum removal
    Fecal Coliform Bacteria                 200/100 mL                   400/100 mL
       c
    pH                                      Daily minimum is equal to or greater than 6.0 and the
                                                    daily maximum is less than or equal to 9.0.
                    Parameter                   Average Monthly              Maximum Daily d
    Total Residual Chlorine                 0.5 mg/L, 600 lb/day         0.75 mg/L
    Footnotes:
    a
        The average monthly and weekly effluent limits are based on the arithmetic mean of the samples
        taken with the exception of fecal coliform, which is based on the geometric mean.
    b
         The average monthly effluent concentration for BOD5 shall not exceed 30 mg/L or 15 percent of the
        respective monthly average influent concentrations, whichever is more stringent.
        The average monthly effluent concentration for TSS shall not exceed 30 mg/L or 15 percent of the
        respective monthly average influent concentrations, whichever is more stringent.
    c
        Indicates the range of permitted values. When pH is continuously monitored, excursions between
        5.0 and 6.0, or 9.0 and 10.0 shall not be considered violations provided no single excursion exceeds
        60 minutes in length and total excursions do not exceed 7 hours and 30 minutes per month. Any
        excursions below 5.0 and above 10.0 are violations. The instantaneous maximum and minimum pH
        shall be reported monthly.
    d
        The maximum daily effluent concentration determined from a continuous measurement is calculated
        as the average of the pollutant concentrations measured over the day.




C. Summary of Compliance With Previous Permit Issued on September 30, 2004
    Ecology staff last conducted a sampling compliance inspection on April 14-15, 2008. A
    compliance inspection report was issued on May 21, 2008. The inspectors found the facility
    to be operating in accordance with the permit and found no violations.
    King County has complied with the effluent limits throughout the duration of the permit
    issued on September 30, 2004. Ecology assessed compliance based on its review of the
    facility’s discharge monitoring reports (DMRs) and on inspections conducted by Ecology.
    The County submits two discharge monitoring reports (DMRs) each month, one for the
    treatment plant discharge and one for the reclaimed water discharge during months in which
    off-site use occurs. The following table summarizes the effluent DMR data (discharge No.
    001) submitted from September 2004 to December 2008. Ecology permits the reclaimed
    water system under Reclaimed Water Permit ST-7445 and its compliance record is described
    in the associated fact sheet. Appendix D provides a complete summary of monthly DMR data
    submitted by the Permittee from September 2004 to April 2009.
Fact Sheet for NPDES Permit WA-002958-1                                                    Page 21 of 101
King County South Wastewater Treatment Plant
    Table 6. Compliance With Effluent Permit Limits
    September 2004 – December 2008
               Parameters                    Average          Max              Min           Permit Limits
    BOD5 – lbs/d, Monthly Avg.                10,397         19,843           4,293            ≤ 36,000
    BOD5 – lbs/d, Max. Weekly Avg.            13,114         29,360           4,800            ≤ 54,000
    BOD5 – mg/L, Monthly Avg.                   16             25                9               ≤ 30
    BOD5 – mg/L, Max. Weekly Avg.               19             30               10               ≤ 45
    TSS – lbs/d, Monthly Avg. TSS             11,360         32,357           4,388            ≤ 36,000
    TSS – lbs/d, Max. Weekly Avg.             15,157         50,971           4,999            ≤ 54,000
    TSS – mg/L, Monthly Avg.                    17             30                8               ≤ 30
    TSS – mg/L, Max. Weekly Avg.                21             41                9               ≤ 45
    Fecal Coliforms, no./100 mL,
                                                74             170              17               ≤ 200
    Monthly
    pH - Daily Low                             6.7             7.4             6.0                ≥ 6.0
    pH - Daily High                            7.4             9.8a            6.8                ≤ 9.0
    Cl2 Residual – mg/L, Monthly Avg.          0.04            0.29            0.00               ≤ 0.5
    Cl2 Residual – mg/L, Max. Daily            0.09            0.75            0.00              ≤ 0.75
    Cl2 Residual – lb/d, Monthly Avg.           20             231              0                ≤ 600
    BOD Removal - %, Monthly Avg.               93              96              86                ≥ 85
    TSS Removal - %, Monthly Avg.               93              97              85                ≥ 85
    Flow - mgd, Monthly Avg.                    76             133             45b                 NA
    Source: NPDES Permit Application.
    a
        The County reports that the pH value of 9.8 is an artifact of hypochlorite dosing the final effluent
        sample line. The County believes that the maximum pH value is likely closer to pH 7.5. The
        hypochlorite dosing is necessary to keep nitrifying bacteria from growing and seeding the final
        effluent sample. Their presence in the sample will artificially increase the effluent BOD result.
    b
        The County reports that the minimum flow of 45-mgd is artificially low by 6-10 mgd. This low flow
        occurred during the summer of 2008 when calibration of the flow meters was changed.

    On November 7, 2008, the wastewater treatment plant had an unauthorized, secondary
    bypass of approximately 1,000 to 2,000 gallons. Primary effluent was unintentionally
    conveyed to the chlorine contact channel during preventative maintenance activities on the
    diversion gates. The County has since modified operational procedures to prevent this
    incident from reoccurring.

D. Wastewater Effluent, Whole Effluent Toxicity, and Sediment Characterizations
    The concentration of pollutants in the discharge was reported in the NPDES application and
    in discharge monitoring reports. Table 7 summarizes those pollutants that the County found
    in detectable quantities as reported in the NPDES form 2A application. Calculations show
    that none of these pollutants have the potential to exceed the state water quality standard at
    the edge of the chronic mixing zone based on the reasonable potential calculations provided
    in Appendix H.
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King County South Wastewater Treatment Plant
    Table 7. Wastewater Effluent Characterization
                              Max. Daily Discharge          Average Daily Discharge
POLLUTANT             Conc.     Units    Mass    Units   Conc.    Units   Mass     Units     # of  ML/
                                                                                           Samples MDL
Antimony              0.67      ug/L     0.45    lbs/d   <0.51    ug/L    <0.30    lbs/d   32        0.5
Arsenic               1.60      ug/L     1.17    lbs/d   1.26     ug/L    0.76     lbs/d   34        0.5
Cadmium               0.30      ug/L     0.17    lbs/d   <0.11    ug/L    <0.064   lbs/d   32        0.1
Chromium              4.07      ug/L     2.28    lbs/d   0.87     ug/L    0.51     lbs/d   32        0.4
Copper                42.4      ug/L     24.01   lbs/d   16.5     ug/L    9.51     lbs/d   32        0.4
Lead                  2.00      ug/L     1.12    lbs/d   0.66     ug/L    0.38     lbs/d   32        0.2
Mercury               0.058     ug/L     0.045   lbs/d   <0.05    ug/L    <0.03    lbs/d   33        0.05
Nickel                4.45      ug/L     2.34    lbs/d   2.99     ug/L    1.78     lbs/d   33        0.3
Silver                0.84      ug/L     0.48    lbs/d   <0.35    ug/L    <0.21    lbs/d   32        0.2
Zinc                  68.0      ug/L     38.5    lbs/d   29.0     ug/L    17.4     lbs/d   33        0.5
Cyanide               0.028     mg/L     14.61   lbs/d   <0.008   mg/L    <5.09    lbs/d   33        0.005
Total Phenolic        0.080     mg/L     47.2    lbs/d   <0.011   mg/L    <6.55    lbs/d   24        0.005-
Compounds                                                                                            0.02
Chloroform            2.18      ug/L     1,565   lbs/d   <1.32    ug/L    <0.802   lbs/d   23        1.32
Methylene Chloride    7         ug/L     4.16    lbs/d   <4.74    ug/L    <2.74    lbs/d   23        5
Toluene               3.86      ug/L     1.845   lbs/d   <1.45    ug/L    <0.78    lbs/d   23        4
1,4-dichlorobenzene   3.93      ug/L     2.82    lbs/d   <1.21    ug/L    <1.21    lbs/d   15        0.57-
                                                                                                     0.6



    Whole Effluent Toxicity Testing
    The County conducted acute and chronic toxicity tests in February 2008, April 2008, July 2008,
    August 2008, and October 2008. Acute toxicity tests were conducted with Daphnia pulex
    (water flea) and Pimephales promelas (fathead minnow). Chronic toxicity tests were conducted
    with Atherinops affinis (topsmelt) and Mysidopsis bahia (Mysid Shrimp). Please refer to
    Appendix G for toxicity test results.

    For acute toxicity, the performance standard is the median survival in 100% effluent being equal
    to or greater than 80% and no individual test result showing less than 65% survival in 100%
    effluent. For the above tests, the median survival in 100% effluent was 90%. No individual test
    resulted in less than 65% survival in 100% effluent. Since the discharge met the performance
    standard for acute toxicity in the previous permit cycle, the proposed permit does not include an
    acute WET limit and instead includes another effluent characterization for acute WET to ensure
    that toxicity has not increased.

    For chronic toxicity, the performance standard is no chronic toxicity test demonstrating a
    statistically-significant difference in response between the control and a test concentration
    equal to the acute critical effluent concentration (ACEC). South WWTP had no chronic
    toxicity near the previous ACEC of 0.43% effluent in any recent test. No chronic WET
    limit is needed. The proposed permit includes the same set of chronic tests at the end of the
    new permit term for submission with the application.
Fact Sheet for NPDES Permit WA-002958-1                                             Page 23 of 101
King County South Wastewater Treatment Plant

     Sediment Characterization
     Ecology has promulgated sediment management standards under Chapter 173-204 WAC.
     The sediment management standards contain numeric chemical and biological criteria that
     protect benthic organisms that live in the sediment of the marine waters of Puget Sound.
     These standards state that Ecology may require permitted facilities to evaluate the potential
     for the discharge to cause a violation of applicable standards.

     In November 2001, King County performed sediment sampling from 0 to 2 cm depth at 13
     sample locations near the two marine outfalls. Sediment samples were analyzed for the 47
     chemicals with numeric criteria in the sediment management standards. All samples met the
     sediment quality standards (SQS) numeric criteria. One sample (RT625SD) had a
     bis(2-ethylhexyl) phthalate concentration of 43 ppm, compared to the SQS criteria of 47
     ppm. All other samples had bis(2-ethylhexyl) phthalate concentrations below 10 ppm. Five
     samples had detection limits for 2-methylphenol that were slightly above the sediment
     quality standards criteria, but were not detected in the sediment nor in the effluent. Most of
     the 47 chemicals were not present at detectable levels. The County measured low
     concentrations of PAH, phthalates and metals in the sediment, but they were below the
     numeric criteria for benthic toxicity.1

     In October 1999, King County performed sediment sampling from 0 to 2 cm depth at 13
     sample locations near the two outfalls. Sediment samples were analyzed for the 47
     chemicals with numeric criteria in the sediment management standards. The County did not
     detect the following four chemicals (2,4-dimethyl phenol, 2-methylphenol, benzyl alcohol,
     and hexachlorobutadiene), but most of the samples had reported detection limits above the
     sediment quality standards numeric criteria. Most of the other 47 chemicals were not
     present at detectable levels below the SQS numeric criteria. The County measured low
     concentrations of PAHs, PCBs, phthalates, and metals in the sediment, but they were below
     the numeric criteria for benthic toxicity.2

     Between 1994 and 1997, King County performed annual sediment sampling from 0 to 2 cm
     depth at locations near the two outfalls.3 In October 1997, the County measured
     concentrations of hexachlorobenzene at three locations (RT700NS, RT625ND, RT625SD)
     that exceeded the sediment quality standards numeric criteria. In October 1995, one location
     (LSDS02) exceeded CSL numeric criteria for benzoic acid. One sample, RT625SD, had
     bis(2-ethylhexyl) phthalate concentration of 42 ppm, compared to the SQS criteria of 47
     ppm.4 For four chemicals (1,2,4-trichlorobenzene, benzyl alcohol, hexachlorobenzene, and
     hexachlorobutadiene) many of the samples had non-detect concentrations with reported
     detection limits above the sediment quality standard numeric criteria.

     Table 8 shows chemicals detected in sediment samples that approach or exceed the SQS
     criteria. Figure 6 shows the locations of the sampling stations.


1
  EIM Data User Study ID RENT01
2
  EIM Data User Study ID RENT99
3
  EIM Data User Study ID RENT9497
4
  Total organic carbon normalized. Sediment Management Standards WAC 173-204-320.
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King County South Wastewater Treatment Plant
    Table 8. Detected Chemicals Above or Approaching SQS Criteria
Sampling Sampling    Chemical Detected in                Sediment              Criteria
 Station   Year           Sediments                   Concentration
RT625SD 2001      Bis(2-ethylhexyl)phthalate      43 ppm                47 ppm
                                                  OC normalized         OC normalized
RT625SD   1997       Bis(2-ethylhexyl)phthalate   42 ppm
                                                  OC normalized
RT625SD   1997       Hexachlorobenzene            1.9 ppm               0.38 ppm
                                                  OC normalized         OC normalized
RT700NS   1997       Hexachlorobenzene            2.5 ppm
                                                  OC normalized
RT625ND   1997       Hexachlorobenzene            0.95 ppm
                                                  OC normalized
LSDS02    1995       Benzoic acid                 1500 ppb dry weight   650 ppb dry weight




    Figure 6.    Sediment Sampling Locations from 1994-2001
   Fact Sheet for NPDES Permit WA-002958-1                                           Page 25 of 101
   King County South Wastewater Treatment Plant
       In summary, past sediment monitoring does not indicate sediment toxicity or a violation of
       the sediment management standards at this site. The proposed permit includes additional
       sediment monitoring to ensure continued compliance because of the large volume of
       discharge, some past instances of detection limits above the SQS numeric criteria, and 1997
       concentrations in the chemical analyses of sediments above SQS near the site.

   E. SEPA Compliance
       Regulation exempts reissuance or modification of any wastewater discharge permit from the
       SEPA process as long as the permit contains conditions that are no less stringent than state rules
       and regulations. The exemption applies only to existing discharges, not to new discharges.

III. PROPOSED PERMIT LIMITS
   Federal and state regulations require that effluent limits in an NPDES permit must be either
   technology- or water quality-based.
   •   Technology-based limits are based upon the treatment methods available to treat specific
       pollutants. Technology-based limits are set by the EPA and published as a regulation, or
       Ecology develops the limit on a case-by-case basis (40 CFR 125.3, and Chapter 173-220 WAC).
   •   Water quality-based limits are calculated so that the effluent will comply with the surface water
       quality standards (Chapter 173-201A WAC), ground water standards (Chapter 173-200 WAC),
       sediment quality standards (Chapter 173-204 WAC), or the National Toxics Rule
       (40 CFR 131.36).
   •   Ecology must apply the most stringent of these limits to each parameter of concern. These
       limits are described below.
   The limits in this permit reflect information received in the application and from supporting reports
   (engineering, hydrogeology, etc.). Ecology evaluated the permit application and determined the
   limits needed to comply with the rules adopted by the state of Washington. Ecology does not
   develop effluent limits for all reported pollutants. Some pollutants are not treatable at the
   concentrations reported, are not controllable at the source, are not listed in regulation, and do not
   have a reasonable potential to cause a water quality violation.
   Nor does Ecology usually develop limits for pollutants that were not reported in the permit
   application but that may be present in the discharge. The permit does not authorize discharge of the
   non-reported pollutants. If significant changes occur in any constituent of the effluent discharge,
   King County is required to notify Ecology [40 CFR 122.42(a)]. King County may be in violation of
   the permit until Ecology modifies the permit to reflect additional discharge of pollutants.

   A. Design Criteria
       Under WAC 173-220-150 (1)(g), flows and waste loadings must not exceed approved design
       criteria. Ecology-approved design criteria for this facility’s treatment plant were obtained from
       the August 1991 Facilities Plan (Metro’s Regional Treatment Plant in Renton, Enlargement III
       Program) and the October 1997 East Division Reclamation Plant Stage 2 Liquid Stream
       Improvements – III2B.1. Both documents were prepared by Brown and Caldwell Consultants
       and associated firms.
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    Table 9: Design Standards for King County South Wastewater Treatment Plant
      Parameter                                                   Design Quantity
      Monthly average flow (max. month)                           144 MGD
      Monthly average dry weather flow (AWDF)                     96 MGD
      Monthly average wet weather flow (AWWF)                     115 MGD
      Instantaneous peak flow                                     325 MGD
      Maximum Month BOD5 influent loading                         251,000 lb/day
      Maximum Month TSS influent loading                          235,000 lb/day
      Design population equivalent                                1,298,000

B. Technology-Based Effluent Limits
    Federal and state regulations define technology-based effluent limits for municipal wastewater
    treatment plants. These effluent limits are given in 40 CFR Part 133 (federal) and in Chapter
    173-221 WAC (state). These regulations are performance standards that constitute all known,
    available, and reasonable methods of prevention, control, and treatment (AKART) for
    municipal wastewater.
    Chapter 173-221 WAC lists the following technology-based limits for pH, fecal coliform,
    BOD5, and TSS:

    Table 10. Technology-Based Limits

    Parameter                   Limit
    pH                      The pH must measure within the range of 6 to 9 standard units.
    Fecal Coliform Bacteria Monthly Geometric Mean = 200 organisms/100 mL
                            Weekly Geometric Mean = 400 organisms/100 mL
    BOD5                    Average Monthly Limit is the most stringent of the following:
    (concentration)             - 30 mg/L
                                - may not exceed fifteen percent (15%) of the average
                                     influent concentration
                            Average Weekly Limit = 45 mg/L
    TSS                     Average Monthly Limit is the most stringent of the following:
    (concentration)             - 30 mg/L
                                - may not exceed fifteen percent (15%) of the average
                                     influent concentration
                            Average Weekly Limit = 45 mg/L
    Chlorine                Average Monthly Limit = 0.5 mg/L
                            Average Weekly Limit = 0.75 mg/L

    Ecology derived the technology-based monthly average limit for chlorine from standard
    operating practices. The Water Pollution Control Federation's Chlorination of Wastewater
    (1976) states that a properly designed and maintained wastewater treatment plant can
    achieve adequate disinfection if a 0.5 mg/L chlorine residual is maintained after fifteen
    minutes of contact time. See also Metcalf and Eddy, Wastewater Engineering, Treatment,
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King County South Wastewater Treatment Plant
    Disposal and Reuse, Third Edition, 1991. A treatment plant that provides adequate
    chlorination contact time can meet the 0.5 mg/L chlorine limit on a monthly average basis.
    According to WAC 173-221-030(11)(b), the corresponding weekly average is 0.75 mg/L.
    The existing permit has chlorine limits of 0.5 mg/L (average monthly) and 0.75 mg/L
    (maximum daily), and the facility is able to comply with it. The proposed permit includes
    the same limit.
    The technology-based mass limits are based on WAC 173-220-130(3)(b) and
    173-221-030(11)(b).
    Monthly effluent mass loadings (lbs/day) = maximum monthly design flow (144 MGD) x
    Concentration limit (30 mg/L) x 8.34 (conversion factor) = mass limit 36,000 lb/day.
    Average weekly effluent mass loadings (lbs/day) = maximum monthly design flow (144 MGD) x
    Concentration limit (45 mg/L) x 8.34 (conversion factor) = mass limit 54,000 lb/day.

C. Surface Water Quality-Based Effluent Limits
    The Washington State surface water quality standards (Chapter 173-201A WAC) are
    designed to protect existing water quality and preserve the beneficial uses of Washington's
    surface waters. Waste discharge permits must include conditions that ensure the discharge
    will meet the surface water quality standards (WAC 173-201A-510). Water quality-based
    effluent limits may be based on an individual waste load allocation or on a waste load
    allocation developed during a basin wide total maximum daily load study (TMDL).

    Numerical Criteria for the Protection of Aquatic Life and Recreation
    Numerical water quality criteria are listed in the water quality standards for surface waters
    (Chapter 173-201A WAC). They specify the maximum levels of pollutants allowed in
    receiving water to protect aquatic life and recreation in and on the water. Ecology uses
    numerical criteria along with chemical and physical data for the wastewater and receiving
    water to derive the effluent limits in the discharge permit. When surface water
    quality-based limits are more stringent or potentially more stringent than technology-based
    limits, the discharge must meet the water quality-based limits.

    Numerical Criteria for the Protection of Human Health
    The U.S. EPA has published 91 numeric water quality criteria for the protection of human
    health that are applicable to dischargers in Washington State (EPA, 1992). These criteria
    are designed to protect humans from exposure to pollutants linked to cancer and other
    diseases, based on consuming fish and shellfish and drinking contaminated surface waters.
    The water quality standards also include radionuclide criteria to protect humans from the
    effects of radioactive substances.

    Narrative Criteria
    Narrative water quality criteria (e.g., WAC 173-201A-240(1); 2006) limit the toxic,
    radioactive, or other deleterious material concentrations that the facility may discharge to
    levels below those which have the potential to:
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    •   Adversely affect designated water uses.
    •   Cause acute or chronic toxicity to biota.
    •   Impair aesthetic values.
    •   Adversely affect human health.
    Narrative criteria protect the specific designated uses of all fresh waters (WAC 173-201A-200,
    2006) and of all marine waters (WAC 173-201A-210, 2006) in the state of Washington.

    Antidegradation
    The purpose of Washington's Antidegradation Policy (WAC 173-201A-300-330; 2006) is to:
    •   Restore and maintain the highest possible quality of the surface waters of Washington.
    •   Describe situations under which water quality may be lowered from its current condition.
    •   Apply to human activities that are likely to have an impact on the water quality of
        surface water.
    •   Ensure that all human activities likely to contribute to a lowering of water quality, at a
        minimum, apply all known, available, and reasonable methods of prevention, control,
        and treatment (AKART).
    •   Apply three tiers of protection (described below) for surface waters of the state.

    Tier I ensures existing and designated uses are maintained and protected and applies to all waters
    and all sources of pollutions. Tier II ensures that waters of a higher quality than the criteria
    assigned are not degraded unless such lowering of water quality is necessary and in the
    overriding public interest. Tier II applies only to a specific list of polluting activities. Tier III
    prevents the degradation of waters formally listed as "outstanding resource waters," and applies
    to all sources of pollution.

    A facility must prepare a Tier II analysis when all three of the following conditions are met:
    •   The facility is planning a new or expanded action.
    •   Ecology regulates or authorizes the action.
    •   The action has the potential to cause measurable degradation to existing water quality at
        the edge of a chronic mixing zone.

    This facility must meet Tier I requirements.
    •   Dischargers must maintain and protect existing and designated uses. Ecology must not
        allow any degradation that will interfere with, or become injurious to, existing or
        designated uses, except as provided for in Chapter 173-201A WAC.
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    Ecology’s analysis described in this section of the fact sheet demonstrates that the existing
    and designated uses of the receiving water will be protected under the conditions of the
    proposed permit.

    Mixing Zones
    A mixing zone is the defined area in the receiving water surrounding the discharge port(s),
    where wastewater mixes with receiving water. Within mixing zones the pollutant
    concentrations may exceed water quality numeric standards, so long as the discharge does not
    interfere with designated uses of the receiving water body (for example, recreation, water
    supply, and aquatic life and wildlife habitat, etc.) The pollutant concentrations outside of the
    mixing zones must meet water quality numeric standards.

    State and federal rules allow mixing zones because the concentrations and effects of most
    pollutants diminish rapidly after discharge, due to dilution. Ecology defines mixing zone
    sizes to limit the amount of time any exposure to the end-of-pipe discharge could harm
    water quality, plants, or fish.

    The state’s water quality standards allow Ecology to authorize mixing zones for the facility’s
    permitted wastewater discharges only if those discharges already receive all known, available,
    and reasonable methods of prevention, control, and treatment (AKART). Mixing zones
    typically require compliance with water quality criteria within a specified distance from the
    point of discharge and use no more than 25% of the available width of the water body for
    dilution. Ecology uses modeling to estimate the amount of mixing within the mixing zone.
    Through modeling Ecology determines the potential for violating the water quality standards at
    the edge of the mixing zone and derive any necessary effluent limits. Steady-state models are
    the most frequently used tools for conducting mixing zone analyses. Ecology chooses values
    for each effluent and for receiving water variables that correspond to the time period when the
    most critical condition is likely to occur (see Ecology’s Permit Writer’s Manual). Each critical
    condition parameter, by itself, has a low probability of occurrence and the resulting dilution
    factor is conservative. The term “reasonable worst-case” applies to these values.

    The mixing zone analysis produces a numerical value called a dilution factor (DF). A dilution
    factor represents the amount of mixing of effluent and receiving water that occurs at the
    boundary of the mixing zone. For example, a dilution factor of 10 means the effluent is 10%
    and the receiving water is 90% of the total volume of water at the boundary of the mixing zone.
    Ecology uses dilution factors with the water quality criteria to calculate reasonable potentials
    and effluent limits. Water quality standards include both aquatic life-based criteria and human
    health-based criteria. The former are applied at both the acute and chronic mixing zone
    boundaries; the latter are applied only at the chronic boundary. The concentration of pollutants
    at the boundaries of any of these mixing zones may not exceed the numerical criteria for that
    zone.

    Each aquatic life acute criterion is based on the assumption that organisms are not exposed
    to that concentration for more than one hour and more often than one exposure in three
    years. Each aquatic life chronic criterion is based on the assumption that organisms are not
    exposed to that concentration for more than four consecutive days and more often than once
    in three years.
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    The two types of human health-based water quality criteria distinguish between those
    pollutants linked to non-cancer effects (non-carcinogenic) and those linked to cancer effects
    (carcinogenic). The human health-based water quality criteria incorporate several exposure
    and risk assumptions. These assumptions include:
    •    A 70-year lifetime of daily exposures.
    •    An ingestion rate for fish or shellfish measured in kg/day.
    •    An ingestion rate of two liters/day for drinking water
    •    A one-in-one-million cancer risk for carcinogenic chemicals.

    This permit authorizes an acute mixing zone, surrounded by a chronic mixing zone around
    the point of discharge (WAC 173-201A-400). The water quality standards impose certain
    conditions before allowing the discharger a mixing zone:

    1.   Ecology must specify both the allowed size and location in a permit.
         The proposed permit specifies the size and location of the allowed mixing zone.

    2.   The facility must fully apply “all known, available, and reasonable methods of
         prevention, control and treatment” (AKART) to its discharge.

         Ecology has determined that the treatment provided at King County’s South WWTP
         meets the requirements of AKART (see “Technology-Based Limits”).

    3.   Ecology must consider critical discharge conditions.

         Surface water quality-based limits are derived for the waterbody’s critical condition (the
         receiving water and waste discharge condition with the highest potential for adverse impact
         on the aquatic biota, human health, and existing or designated waterbody uses). The
         critical discharge condition is often pollutant-specific or waterbody-specific.

         Critical discharge conditions are those conditions that result in reduced dilution or
         increased effect of the pollutant. Factors affecting dilution include the depth of water,
         the density stratification in the water column, the currents, and the rate of discharge.
         Density stratification is determined by the salinity and temperature of the receiving
         water. Temperatures are warmer in the surface waters in summer. Therefore, density
         stratification is generally greatest during the summer months. Density stratification
         affects how far up in the water column a freshwater plume may rise. The rate of
         mixing is greatest when an effluent is rising. The effluent stops rising when the mixed
         effluent is the same density as the surrounding water. After the effluent stops rising,
         the rate of mixing is much more gradual. Water depth can affect dilution when a plume
         might rise to the surface when there is little or no stratification. Ecology uses the water
         depth at mean lower low water (MLLW) for marine waters. Ecology’s Permit Writer’s
         Manual describes additional guidance on criteria/design conditions for determining
         dilution factors. The manual can be obtained from Ecology’s website at:
         http://www.ecy.wa.gov/biblio/92109.html.
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         Ecology used the following critical conditions to model the discharge:
         •   Water depth at MLLW of 625 feet.
         •   50th percentile current speeds of 0.069 m/sec for chronic and human health mixing
             zones (at Station 46, depth = 191 m).
         •   10th or 90th percentile current speeds of 0.021 and 0.14 m/sec, respectively for
             acute mixing zone (at Station 46, depth = 191 m)
         •   Maximum average monthly effluent flow of 144 MGD for chronic and human
             health non-carcinogen.
         •   Annual average flow of 106 MGD for human health carcinogen.
         •   Maximum daily flow of 235 million gallons per day (MGD) for acute mixing zone.
         •   1 DAD MAX Effluent temperature of 22.2 degrees C.
         Ambient data at critical conditions in the vicinity of the outfall was taken from Effluent
         Dilution Modeling for South Wastewater Treatment Plant Outfall study conducted in
         March 2009.

    4.   Supporting information must clearly indicate the mixing zone would not:
         •    Have a reasonable potential to cause the loss of sensitive or important habitat.
         •    Substantially interfere with the existing or characteristic uses.
         •    Result in damage to the ecosystem.
         •    Adversely affect public health.
         Ecology established Washington State water quality criteria for toxic chemicals using
         EPA criteria. EPA developed the criteria using toxicity tests with numerous organisms
         and set the criteria to generally protect the species tested and to fully protect all
         commercially- and recreationally-important species.

         EPA sets acute criteria for toxic chemicals assuming organisms are exposed to the
         pollutant at the criteria concentration for one hour. They set chronic standards assuming
         organisms are exposed to the pollutant at the criteria concentration for four days.
         Dilution modeling under critical conditions generally shows that both acute and chronic
         criteria concentrations are reached within minutes of being discharged.

         The discharge plume does not impact drifting and non-strong swimming organisms
         because they cannot stay in the plume close to the outfall long enough to be affected.
         Strong swimming fish could maintain a position within the plume, but they can also
         avoid the discharge by swimming away. Mixing zones generally do not affect benthic
         organisms (bottom dwellers) because the buoyant plume rises in the water column.
         Ecology has additionally determined that the effluent will not exceed 33 degrees C for
         more than two seconds after discharge; and that the temperature of the water will not
         create lethal conditions or blockages to fish migration.
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         Ecology evaluates the cumulative toxicity of an effluent by testing the discharge with
         whole effluent toxicity (WET) testing.

         Ecology reviewed the above information, the specific information on the characteristics
         of the discharge, the receiving water characteristics, and the discharge location. Based
         on this review, Ecology concluded that the discharge does not have a reasonable
         potential to cause the loss of sensitive or important habitat, substantially interfere with
         existing or characteristics uses, result in damage to the ecosystem, or adversely affect
         public health if the permit limits are met.

    5.   The discharge/receiving water mixture must not exceed water quality criteria
         outside the boundary of a mixing zone.
         Ecology conducted a reasonable potential analysis, using procedures established by the
         EPA and by Ecology, for each pollutant and concluded the discharge/receiving water
         mixture will not violate water quality criteria outside the boundary of the mixing zone
         if permit limits are met.

    6.   The size of the mixing zone and the concentrations of the pollutants must be
         minimized.

         At any given time, the effluent plume uses only a portion of the acute and chronic
         mixing zone, which minimizes the volume of water involved in mixing. Because tidal
         currents change direction, the plume orientation within the mixing zone changes. The
         plume rises through the water column as it mixes, therefore much of the receiving water
         volume at lower depths in the mixing zone is not mixed with discharge. Similarly,
         because the discharge may stop rising at some depth due to density stratification, waters
         above that depth will not mix with the discharge. Ecology determined it is impractical
         to specify in the permit the actual, much more limited volume in which the dilution
         occurs as the plume rises and moves with the current.

         Ecology minimizes the size of mixing zones by requiring dischargers to install diffusers
         when they are appropriate to the discharge and the specific receiving waterbody. When
         a diffuser is installed, the discharge is more completely mixed with the receiving water
         in a shorter time. Ecology also minimizes the size of the mixing zone (in the form of
         the dilution factor) using design criteria with a low probability of occurrence. For
         example, Ecology uses the expected 95th percentile pollutant concentration, the 90th
         percentile background concentration, the centerline dilution factor, and the lowest flow
         occurring once in every ten years to perform the reasonable potential analysis.

         Because of the above reasons, Ecology has effectively minimized the size of the mixing
         zone authorized in the proposed permit.

    7.   Maximum size of mixing zone.

         The authorized mixing zone does not exceed the maximum size restriction.
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    8.   Acute Mixing Zone.

         •   The discharge/receiving water mixture must comply with acute criteria as
             near to the point of discharge as practicably attainable.
             Ecology determined the acute criteria will be met at 10% of the distance of the
             chronic mixing zone at the ten-year low flow.
         •   The pollutant concentration, duration, and frequency of exposure to the
             discharge will not create a barrier to migration or translocation of indigenous
             organisms to a degree that has the potential to cause damage to the ecosystem.
             As described above, the toxicity of any pollutant depends upon the exposure, the
             pollutant concentration, and the time the organism is exposed to that concentration.
             Authorizing a limited acute mixing zone for this discharge assures that it will not
             create a barrier to migration. The effluent from this discharge will rise as it enters
             the receiving water, assuring that the rising effluent will not cause translocation of
             indigenous organisms near the point of discharge (below the rising effluent).
         •   Comply with size restrictions.
             The mixing zone authorized for this discharge complies with the size restrictions
             published in Chapter 173-201A WAC.

    9.   Overlap of Mixing Zones.

         For the marine discharge, please see Appendix F for acute and chronic mixing zones
         diagrams. South WWTP’s mixing zones do not overlap another discharger’s mixing zones.
         For the Green River outfall, the mixing zone cannot extend more than 310 feet downstream
         and more than 100 feet upstream from the diffusers. The mixing zone cannot utilize
         greater than 25 percent of the flow and cannot occupy greater than 25 percent of the width
         of the river.

D. Designated Uses and Surface Water Quality Criteria
    Applicable designated uses and surface water quality criteria are defined in Chapter 173-201A
    WAC. In addition, the U.S. EPA set human health criteria for toxic pollutants (EPA 1992).
    Criteria applicable to this facility’s discharge are summarized below in Tables 11 - 14.

    Marine Water Discharge (Outfall 001):

    •    Aquatic life uses are designated using the following general categories. All indigenous
         fish and non-fish aquatic species must be protected in waters of the state.

         (a) Extraordinary quality salmonid and other fish migration, rearing, and spawning;
             clam, oyster, and mussel rearing and spawning; crustaceans and other shellfish
             (crabs, shrimp, crayfish, scallops, etc.) rearing and spawning.
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         (b) Excellent quality salmonid and other fish migration, rearing, and spawning; clam,
             oyster, and mussel rearing and spawning; crustaceans and other shellfish (crabs,
             shrimp, crayfish, scallops, etc.) rearing and spawning.

         (c) Good quality salmonid migration and rearing; other fish migration, rearing, and
             spawning; clam, oyster, and mussel rearing and spawning; crustaceans and other
             shellfish (crabs, shrimp, crayfish, scallops, etc.) rearing and spawning.

         (d) Fair quality salmonid and other fish migration.

        The South WWTP’s outfall discharges to Puget Sound at a location that is classified as
        extraordinary marine waters. The Aquatic Life Uses and associated criteria for
        extraordinary marine waters are identified below.

    Table 11. Aquatic Life Uses and Associated Criteria
    Extraordinary quality
    Temperature Criteria – Highest 1D MAX         13°C (55.4°F)
    Dissolved Oxygen Criteria – Lowest 1-Day      7.0 mg/L
    Minimum
    Turbidity Criteria                            • 5 NTU over background when the background is
                                                    50 NTU or less; or
                                                  • A 10 percent increase in turbidity when the
                                                    background turbidity is more than 50 NTU.
    pH Criteria                                   pH must be within the range of 7.0 to 8.5 with a
                                                  human-caused variation within the above range of
                                                  less than 0.2 units.

    •    To protect shellfish harvesting, fecal coliform organism levels must not exceed a
         geometric mean value of 14 colonies/100 mL, and not have more than 10 percent of all
         samples (or any single sample when less than ten sample points exist) obtained for
         calculating the geometric mean value exceeding 43 colonies/100 mL.

    •    The recreational uses are primary contact recreation and secondary contact recreation.

    For the South WWTP’s discharge to Puget Sound, the recreational uses for this receiving
    water are identified as primary contact, as shown below.


    Table 12. Recreational Uses
    Recreational use     Criteria
    Primary Contact      Fecal coliform organism levels must not exceed a geometric mean value of 14
    Recreation           colonies/100 mL, with not more than 10 percent of all samples (or any single
                         sample when less than ten sample points exist) obtained for calculating the
                         geometric mean value exceeding 43 colonies/100 mL.

   •    The miscellaneous marine water uses are wildlife habitat, harvesting, commerce and
        navigation, boating, and aesthetics.
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    Freshwater Discharge (Maintenance & Emergency Outfall):
    • Aquatic Life Uses are designated based on the presence of, or the intent to provide
        protection for, the key uses. All indigenous fish and non-fish aquatic species must be
        protected in waters of the state in addition to the key species. The Aquatic Life Uses
        for the Green River at the Emergency Outfall location are identified below.

    Table 13.     Aquatic Life Uses & Associated Criteria
    Salmonid Spawning, Rearing, and Migration
    Temperature Criteria – Highest 7DAD MAX          17.5°C (63.5°F)
    Dissolved Oxygen Criteria – Lowest 1-Day         8.0 mg/L
    Minimum
    Turbidity Criteria                               • 5 NTU over background when the background is
                                                       50 NTU or less; or
                                                     • A 10 percent increase in turbidity when the
                                                       background turbidity is more than 50 NTU.
    Total Dissolved Gas Criteria                     Total dissolved gas shall not exceed 110 percent
                                                     of saturation at any point of sample collection.
    pH Criteria                                      pH shall be within the range of 6.5 to 8.5 with a
                                                     human-caused variation within the above range of
                                                     less than 0.5 units.

    •   The recreational uses are extraordinary primary contact recreation, primary contact
        recreation, and secondary contact recreation. The recreational uses for this receiving
        water are identified below.

    Table 14.     Recreational Uses and Associated Criteria
    Recreational Use      Criteria
    Primary Contact       Fecal coliform organism levels must not exceed a geometric mean value of 100
    Recreation            colonies /100 mL, with not more than 10 percent of all samples (or any single
                          sample when less than ten sample points exist) obtained for calculating the
                          geometric mean value exceeding 200 colonies/100 mL.

    •   The water supply uses are domestic, agricultural, industrial, and stock watering.

    •   The miscellaneous freshwater uses are wildlife habitat, harvesting, commerce and
        navigation, boating, and aesthetics.

E. Evaluation of Surface Water Quality-Based Effluent Limits for Numeric Criteria

    Puget Sound Outfall No. 001
    Pollutants in an effluent may affect the aquatic environment near the point of discharge
    (near-field) or at a considerable distance from the point of discharge (far-field). Toxic
    pollutants, for example, are near-field pollutants—their adverse effects diminish rapidly with
    mixing in the receiving water. Conversely, a pollutant such as biological oxygen demand
    (BOD) is a far-field pollutant whose adverse effect occurs away from the discharge even after
    dilution has occurred. Thus, the method of calculating surface water quality-based effluent
    limits varies with the point at which the pollutant has its maximum effect.
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    With technology-based controls (AKART), predicted pollutant concentrations in the
    discharge may exceed water quality criteria. Ecology therefore authorizes a mixing zone in
    accordance with the geometric configuration, flow restriction, and other restrictions imposed
    on mixing zones by Chapter 173-201A WAC.

    Chronic Mixing Zone (Outfall No. 001)
    WAC 173-201A-400(7)(b) specifies that mixing zones must not extend in any horizontal
    direction from the discharge ports for a distance greater than 200 feet plus the depth of water
    over the discharge ports as measured during MLLW.
    The horizontal distance of the chronic mixing zone is 825 feet. The mixing zone extends
    from the seabed to the top of the water surface.

    Acute Mixing Zone (Outfall No. 001)
    WAC 173-201A-400(8)(b) specifies that in estuarine waters a zone where acute criteria may be
    exceeded must not extend beyond 10% of the distance established for the chronic zone. The
    acute mixing zone for Outfall 001 extends 82.5 feet in any direction from any discharge port.

    Dilution Factors
    Ecology provided a thorough review of the County’s data, dilution factors, and modeling in
    June 2009. Ecology verified that the County used conservative assumptions and provided
    rigorous modeling to obtain dilution factors. The dilution ratios predicted from the current
    modeling effort are substantially different (lower) from those predicted in the previous
    analysis, and are described in the table below. Ecology revised the dilution factors because
    the County 1) used new and improved computer models, 2) collected additional density
    profile data; and 3) updated plant flow rates. Ecology considers the dilution factors in the
    proposed permit more up-to-date and representative than the factors in the previous permit.
    Note that all of the dilution factors decreased from the previous permit.

    Table 15.         Comparison of Dilution Ratios
        Outfall      Chronic   Zone of Acute        Proposed    Current    Proposed        Current
                   Mixing Zone    Criteria           Chronic    Chronic      Acute          Acute
                     Radius     Exceedance           Dilution   Dilution    Dilution       Dilution
                     (feet) a     (feet) a            Ratio      Ratio       Ratio          Ratio
    South               825              82.5         225:1      429:1       186:1           233:1
    WWTP
    a
        – as measured horizontally from each port

    Ecology determined the dilution factors that occur within these zones at the critical
    condition using UM3 and NRFIELD/RSB model components. The dilution ratio for this
    permit is listed in Table 16:
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    Table 16.      Dilution Ratio for Outfall No. 001

                   Criteria                  Acute           Chronic
    Aquatic Life                              186:1            225:1
    Human Health, Carcinogen                                   428:1
    Human Health, Non-carcinogen                               428:1

    Ecology determined the impacts of dissolved oxygen deficiency, temperature, pH, fecal
    coliform, chlorine, ammonia, metals, nutrients and other toxics as described below, using the
    dilution ratios in the above tables. The derivation of surface water quality-based limits also
    takes into account the variability of pollutant concentrations in both the effluent and the
    receiving water.
    BOD5—With technology-based limits, this discharge results in a small amount of BOD loading
    relative to the large amount of dilution in the receiving water at critical conditions.
    Technology-based limits will ensure that dissolved oxygen criteria are met in the receiving water.
    Temperature—The state temperature standards (WAC 173-201A-200-210 and 600-612)
    include multiple elements:
        •    Annual summer maximum threshold criteria (June 15 to September 15).
        •    Supplemental spawning and rearing season criteria (September 15 to June 15).
        •    Incremental warming restrictions.
        •    Protections against acute effects.
        Ecology evaluates each criterion independently to determine reasonable potential and
        derive permit limits.

        •    Annual summer maximum and supplementary spawning/rearing criteria.
             Each water body has an annual maximum temperature criterion [WAC
             173-201A-200(1)(c), 210(1)(c), and Table 602]. These threshold criteria (for
             example, 12, 16, 17.5, 20°C) protect specific categories of aquatic life by
             controlling the effect of human actions on summer temperatures.
             Some waters have an additional threshold criterion to protect the spawning and
             incubation of salmonids (9°C for char and 13°C for salmon and trout) [WAC
             173-201A-602, Table 602]. These criteria apply during specific date-windows.
             The threshold criteria apply at the edge of the chronic mixing zone. Criteria for
             most fresh waters are expressed as the highest 7-Day average of daily maximum
             temperature (7-DADMax). The 7-DADMax temperature is the arithmetic average
             of seven consecutive measures of daily maximum temperatures. Criteria for
             marine waters and some fresh waters are expressed as the highest 1-Day annual
             maximum temperature (1-DMax).
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King County South Wastewater Treatment Plant

        •   Incremental warming criteria.
            The water quality standards limit the amount of warming human sources can cause
            under specific situations [WAC 173-201A-200(1)(c)(i)-(ii), 210(1)(c)(i)-(ii)]. The
            incremental warming criteria apply at the edge of the chronic mixing zone.
            At locations and times when background temperatures are cooler than the assigned
            threshold criterion, point sources are permitted to warm the water by only a
            defined increment. These increments are permitted only to the extent doing so
            does not cause temperatures to exceed either the annual maximum or supplemental
            spawning criteria.
            At locations and times when a threshold criterion is being exceeded due to natural
            conditions, all human sources, considered cumulatively, must not warm the water
            more than 0.3°C above the naturally warm condition.
            When Ecology has not yet completed a TMDL, our policy allows each point
            source to warm water at the edge of the chronic mixing zone by 0.3°C. This is true
            regardless of the background temperature and even if doing so would cause the
            temperature at the edge of a standard mixing zone to exceed the numeric threshold
            criteria. Allowing a 0.3°C warming for each point source is reasonable and
            protective where the dilution factor is based on 25% or less of the critical flow.
            This is because the fully mixed effect on temperature will only be a fraction of the
            0.3°C cumulative allowance (0.075°C or less) for all human sources combined.

        •   Temperature Acute Effects.
            Instantaneous lethality to passing fish: The upper 99th percentile daily
            maximum effluent temperature must not exceed 33°C; unless a dilution analysis
            indicates ambient temperatures will not exceed 33°C 2-seconds after discharge.
            General lethality and migration blockage: Measurable (0.3°C) increases in
            temperature at the edge of a chronic mixing zone are not allowed when the
            receiving water temperature exceeds either a 1DMax of 23°C or a 7DADMax of
            22°C.
            Lethality to incubating fish: Human actions must not cause a measurable (0.3°C)
            warming above 17.5°C at locations where eggs are incubating.

        •   Temperature Chronic Effects.
            1.   Annual summer maximum.
                 Ecology calculated the reasonable potential for the discharge to exceed the
                 annual summer maximum, the supplementary spawning criterion, and the
                 incremental warming criteria at the edge of the chronic mixing zone during
                 critical condition(s). No reasonable potential exists to exceed the temperature
                 criterion where:
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King County South Wastewater Treatment Plant
                  (Criterion + 0.3) > Criterion + [(Teffluent95 – Criterion)/DF].
                  (13 + 0.3) > 13 + [(22.5 – 13)/225].
                  13.3 > 13.04
                  Therefore, the proposed permit does not include a temperature limit. The permit
                  requires additional monitoring of effluent and ambient temperatures. Ecology
                  will reevaluate the reasonable potential during the next permit renewal.

             2.   Incremental warming criteria.

                  Some waters are naturally incapable of meeting their assigned threshold
                  temperature criteria. At locations and times when a threshold criterion is being
                  exceeded due to natural conditions, all human sources, considered cumulatively,
                  must not warm the water more than 0.3°C above the naturally warm condition.

                  When Ecology has not yet completed a TMDL, our policy allows each point
                  source to warm water at the edge of the chronic mixing zone by 0.3°C. This is
                  true regardless of the background temperature and even if doing so would cause
                  the temperature at the edge of a standard mixing zone to exceed the numeric
                  threshold criteria. Allowing a 0.3°C warming for each point source is reasonable
                  and protective where the dilution factor is based on 25 percent or less of the
                  critical flow. This is because the fully mixed effect on temperature will be only a
                  fraction (0.075°C or less) of the 0.3°C cumulative allowance for all human
                  sources combined.

                  South WWTP reported a maximum effluent temperature of 22.2°C on their
                  NPDES application. Using the dilution ratio of 225:1 (receiving water : effluent)
                  and maximum daily temperature of 14.0°C for the receiving water and 22.2°C
                  for the effluent, the predicted maximum daily temperature inside the dilution
                  zone is ((225x14.0)+(1x22.2))/(225+1) = 14.04°C. Thus, under the worst case
                  scenario, the effluent discharge from this facility results in warming of the
                  ambient temperature by 0.04°C, which is less than the allowable warming
                  temperature of 0.3°C.
                  Since the discharge does not have a potential to violate the water quality standards
                  for temperature in the receiving water, Ecology placed no limits in the permit for
                  effluent temperature. To acquire ambient temperature and effluent temperature
                  data, the proposed permit requires the South WWTP to continue to monitor these
                  temperatures. The need for a limit will be evaluated during the next permit cycle.


    pH—Compliance with the technology-based limits of 6.0 to 9.0 will assure compliance with the
    water quality standards of surface waters because of the high buffering capacity of marine water.
    Fecal Coliform—Ecology modeled the numbers of fecal coliform by simple mixing analysis
    using the maximum day discharge (years 2004-2008) of 2,075 organisms per 100 ml and a
    dilution factor of 225.
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King County South Wastewater Treatment Plant
    Under critical conditions, modeling predicts no violation of the water quality criterion for
    fecal coliform. Therefore, the proposed permit includes the technology-based effluent limit
    for fecal coliform bacteria.
    Toxic Pollutants—Federal regulations (40 CFR 122.44) require Ecology to place limits in
    NPDES permits on toxic chemicals in an effluent whenever there is a reasonable potential for
    those chemicals to exceed the surface water quality criteria. Ecology does not exempt facilities
    with technology-based effluent limits from meeting the surface water quality standards.
    The following toxic pollutants are present in the discharge: chlorine, ammonia, and heavy
    metals. Ecology conducted a reasonable potential analysis (see Appendix H) on these
    parameters to determine whether it would require effluent limits in this permit.
    Ammonia's toxicity depends on that portion which is available in the unionized form. The
    amount of unionized ammonia depends on the temperature, pH, and salinity of the receiving
    marine water. To evaluate ammonia toxicity, Ecology used the available receiving water
    information for ambient station LSTN01 and Ecology spreadsheet tools.
    Valid ambient background data was available for arsenic, cadmium, chromium, copper, lead,
    mercury, nickel, and zinc (see Appendix H). Ecology used all applicable data to evaluate
    reasonable potential for this discharge to cause a violation of water quality standards.
    Ecology determined that ammonia, arsenic, cadmium, chromium, copper, cyanide, lead,
    mercury, nickel, silver, and zinc pose no reasonable potential to exceed the water quality
    criteria at the critical condition using procedures given in EPA, 1991 (Appendix H) and as
    described above. Ecology’s determination assumes that this facility meets the other effluent
    limits of this permit.

    Ecology derived effluent limits for the toxic pollutant chlorine, determined to have a
    reasonable potential to cause a violation of the water quality standards. Ecology calculated
    effluent limits using methods from EPA, 1991 as shown in Appendix H.

    Ecology used new dilution modeling results (more restrictive) to determine new total residual
    chlorine limits for the proposed permit. Ecology derived the new limits based on the state water
    quality standards of 13 μg/L for acute and 7.5 μg/L for chronic along with an acute dilution
    factor of 186:1 and a chronic dilution factor of 225:1 (refer to Appendix H—Technical
    Calculations). The resulting permit limits would be an average monthly total residual chlorine
    limit of 924 μg/L and a maximum daily total residual chlorine limit of 2,418 μg/L. However,
    the technology, guidance-based limit for chlorine is more stringent than the water quality-based
    limit at 500 µg/L (Average Monthly Limit) and 750 µg/L (Maximum Daily Limit). The
    anti-backsliding provision under the federal regulations [CFR 122.44(l)] requires that the
    chlorine limit be based on the more stringent limit established in the previous permit since it has
    been shown to be technologically achievable.
    The resultant effluent limits are as follows:
    Chlorine 0.5 mg/L (average monthly) and 0.75 mg/L (average weekly)
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King County South Wastewater Treatment Plant
    Freshwater Dilution Factors – Green River Outfall No. 002 (Maintenance Only)
    Ecology determined the dilution ratio of effluent to receiving water that occurs within the
    freshwater zones based on bulk dilution. The resultant dilution ratio is:

    Table 17.    Dilution Ratio - Green River Outfall No. 002
        Green River Outfall                  Acute                         Chronic
    Aquatic Life – Maintenance                9:1                       Not Applicable
    Aquatic Life – Emergency         Permitted Under S5.F               Not Applicable

    Ecology determined the acute dilution ratio based on bulk dilution achieved under the
    conditions expected during use of the outfall for maintenance purposes. King County may
    discharge only when the river flow is at least 1000 cfs (cubic feet per second). The rate of
    discharge anticipated during a maintenance event is limited to no more than an average of
    28 cfs. Ecology used these assumptions for the previous permit and verified them for this
    permit. Based on these assumptions, the bulk dilution using the entire river is 36:1
    (1000/28=36). The regulation permits only 25% of the river width to be utilized; therefore,
    the effective acute dilution ratio is 9:1 during a maintenance event. Ecology expects that
    maintenance discharges will only occur for short periods of time and therefore chronic water
    quality standards would not apply.
    Ecology did not determine a mixing zone for the emergency use of the Green River outfall.
    The Green River outfall is implicitly permitted under Special Condition S5.F and explicitly
    permitted under Special Condition S1.B for emergency use. Effluent limits were not
    imposed for emergency use because it is assumed that such use will occur under extreme
    and unpredictable circumstances.
    BOD5—Ecology predicts a violation of the dissolved oxygen criterion for the receiving
    water under critical conditions with the technology-based limit. Ecology determined the
    impact of BOD on the receiving water based on a discharge limit of 15 mg/L and a dilution
    of 9:1. This discharge limit could produce a drop in dissolved oxygen in the river by as
    much as 1.67 mg/L based on worst case assumptions. Based on the short duration of this
    discharge, Ecology believes this limit will protect the receiving water.
    Temperature and pH—The impact of pH and temperature were modeled using the
    calculations from EPA, 1988. The input variables were dilution factor 9, upstream temperature
    17.2oC, upstream pH 7.5, upstream alkalinity 50(as mg CaCO3/L), effluent temperature 20oC,
    effluent pH of 6, and effluent alkalinity 68.8 (as mg CaCO3/L). (Refer to Appendix H.)
    Under critical conditions there is no predicted violation of the water quality standards for
    surface waters. Therefore, the no technology-based limit was placed in the permit for
    temperature. A technology-based effluent limit for pH was placed in the permit.
    Fecal Coliform—The numbers of fecal coliform were modeled by simple mixing analysis
    using the technology-based limit of 200 organisms per 100 ml and a dilution factor of 9.
    The resulting fecal coliform at the edge of the dilution zone would be 22.1 organisms per
    100 ml.
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King County South Wastewater Treatment Plant
     Under critical conditions there is no predicted violation of the water quality standards for
     surface waters with the technology-based limit. Therefore, the technology-based effluent
     limit for fecal coliform bacteria was placed in the proposed permit.
     Toxic Pollutants—Federal regulations (40 CFR 122.44) require NPDES permits to contain
     effluent limits for toxic chemicals in an effluent whenever there is a reasonable potential for
     those chemicals to exceed the surface water quality criteria. This process occurs
     concurrently with the derivation of technology-based effluent limits. Facilities with
     technology-based effluent limits defined in regulation are not exempted from meeting the
     water quality standards for surface waters or from having surface water quality-based
     effluent limits.
     Due to the infrequency and short duration of discharges to the Green River, the only toxicant
     considered was chlorine. Ecology conducted a reasonable potential analysis (see Appendix H)
     on chlorine to determine whether or not it would require effluent limits in this permit.
     Ecology derived effluent limits for chlorine, which showed a reasonable potential to cause a
     violation of the water quality standards. Effluent limits were calculated using methods from
     EPA, 1991 as shown in Appendix H.
     The resultant effluent limits are as follows:
     Chlorine 171 μg/L.

F.   Whole Effluent Toxicity
     The water quality standards for surface waters forbid discharge of effluent that causes toxic
     effects in the receiving waters. Many toxic pollutants cannot be measured by commonly
     available detection methods. However, laboratory tests can measure toxicity directly by
     exposing living organisms to the wastewater and measuring their responses. These tests
     measure the aggregate toxicity of the whole effluent, so this approach is called whole effluent
     toxicity (WET) testing. Some WET tests measure acute toxicity and other WET tests measure
     chronic toxicity.
     •   Acute toxicity tests measure mortality as the significant response to the toxicity of the
         effluent. Dischargers who monitor their wastewater with acute toxicity tests find early
         indications of any potential lethal effect of the effluent on organisms in the receiving
         water.
     •   Chronic toxicity tests measure various sublethal toxic responses, such as retarded
         growth or reduced reproduction. Chronic toxicity tests often involve either a complete
         life cycle test on an organism with an extremely short life cycle, or a partial life cycle
         test during a critical stage of a test organism's life. Some chronic toxicity tests also
         measure organism survival.
     Ecology-accredited WET testing laboratories use the proper WET testing protocols, fulfill
     the data requirements, and submit results in the correct reporting format. Accredited
     laboratory staff knows about WET testing and how to calculate an NOEC, LC50, EC50, IC25,
     etc. Ecology gives all accredited labs the most recent version of Ecology Publication No.
     WQ-R-95-80, Laboratory Guidance and Whole Effluent Toxicity Test Review Criteria
Fact Sheet for NPDES Permit WA-002958-1                                          Page 43 of 101
King County South Wastewater Treatment Plant
    (http://www.ecy.wa.gov/biblio/9580.html), which is referenced in the permit. Ecology
    recommends that King County send a copy of the acute or chronic toxicity sections(s) of its
    NPDES permit to the laboratory.
    WET testing conducted during effluent characterization showed no reasonable potential for
    effluent discharges to cause receiving water acute toxicity. All individual acute WET tests
    had greater than 65% survival in 100% effluent, and the median survival in 100% effluent
    was 90%. Since the acute toxicity tests passed the performance standard, the proposed
    permit will not impose an acute WET limit. King County must retest the effluent before
    submitting an application for permit renewal.
    •   If this facility makes process or material changes which, in Ecology's opinion, increase
        the potential for effluent toxicity, then Ecology may (in a regulatory order, by permit
        modification, or in the permit renewal) require the facility to conduct additional effluent
        characterization.
    •   If WET testing conducted for submittal with a permit application fails to meet the
        performance standards in WAC 173-205-020, Ecology will assume that effluent
        toxicity has increased. King County may demonstrate to Ecology that effluent toxicity
        has not increased, by performing additional WET testing after the process or material
        changes have been made.
    WET testing conducted during effluent characterization showed no reasonable potential for
    effluent discharges to cause receiving water chronic toxicity. The proposed permit will not
    impose a chronic WET limit. King County must retest the effluent before submitting an
    application for permit renewal.
    •   If this facility makes process or material changes which, in Ecology's opinion, increase
        the potential for effluent toxicity, then Ecology may (in a regulatory order, by permit
        modification, or in the permit renewal) require the facility to conduct additional effluent
        characterization
    •   If WET testing conducted for submittal with a permit application fails to meet the
        performance standards in WAC 173-205-020, Ecology will assume that effluent
        toxicity has increased. King County may demonstrate to Ecology that effluent toxicity
        has not increased by performing additional WET testing after the process or material
        changes have been made.

G. Human Health
    Washington’s water quality standards include 91 numeric human health-based criteria that
    Ecology must consider when writing NPDES permits. These criteria were established in
    1992 by the U.S. EPA in its National Toxics Rule (40 CFR 131.36). The National Toxics
    Rule allows states to use mixing zones to evaluate whether discharges comply with human
    health criteria.
    Ecology determined the effluent may contain chemicals of concern for human health, based
    on (1) the facility’s status as an EPA major discharger, and (2) data or information
    indicating regulated chemicals occur in the discharge.
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King County South Wastewater Treatment Plant
    Ecology evaluated the discharge's potential to violate the water quality standards as required by
    40 CFR 122.44(d) by following the procedures published in the Technical Support Document for
    Water Quality-Based Toxics Control (EPA/505/2-90-001) and Ecology's Permit Writer's Manual
    to make a reasonable potential determination. The evaluation showed that the discharge has no
    reasonable potential to cause a violation of water quality standards, and an effluent limit is not
    needed.

H. Sediment Quality
    The aquatic sediment standards (Chapter 173-204 WAC) protect aquatic biota and human
    health. Under these standards Ecology may require a facility to evaluate the potential for its
    discharge to cause a violation of sediment standards (WAC 173-204-400). You can obtain
    additional information about sediments at the Aquatic Lands Cleanup Unit website.
    http://www.ecy.wa.gov/programs/tcp/smu/sediment.html

    Ecology determined that the South WWTP discharge may have the potential to cause a
    violation of the sediment quality standards because:

    •   In some of the past testing, detection limits were above the SQS numeric criteria.

    •   In 1997, three locations had detected concentrations of hexachlorobenzene above the SQS
        numeric criteria for benthic toxicity.

    •   King County has previously collected sediment samples from the top 2 centimeters of
        sediment in accordance with past permit requirements. Ecology now bases compliance
        on the top 10 centimeters of sediment, which is the biologically active zone.

    •   King County has not performed sediment chemical analysis since 2001, and has not been
        required to conduct biological tests at locations near the outfalls.

    The proposed permit includes a condition requiring King County to:

    •   Sample and analyze sediments in the vicinity of South WWTP’s outfall to characterize
        sediment quality (the nature and extent of chemical contamination and biological toxicity)
        in the vicinity of the Permittee’s discharge locations. Specifically, sediment sampling will
        be required for 0 to 10 cm depth at 8 locations near the two outfalls. Chemical analysis of
        the 47 chemicals in the sediment management standards plus conventional analytes will be
        required at all 8 sites. Bioassays will be performed, if the chemical concentrations are near
        or above the sediment management standards numeric chemical criteria.

    •   The Permittee must develop a Sampling and Analysis Plan in accordance with the
        Sediment Sampling and Analysis Plan Appendix. The Sampling and Analysis Plan must
        be approved by the Department of Ecology before performing sediment sampling. After
        the sediment sampling is completed, the Permittee must submit a Sediment Data Report
        and Environmental Information Management (EIM) templates to the Department of
        Ecology for review and approval.

    •   If the sediment evaluation shows toxicity at any station, the Permittee must perform
        additional testing to investigate the source of sediment toxicity.
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King County South Wastewater Treatment Plant
I.   Ground Water Quality Limits
     The ground water quality standards (Chapter 173-200 WAC) protect beneficial uses of
     ground water. Permits issued by Ecology must not allow violations of those standards
     (WAC 173-200-100).
     King County South WWTP does not discharge wastewater to the ground. No permit limits
     are required to protect ground water.

J.   Comparison of Effluent Limits With the Previous Permit Issued on September 30, 2004

     There were no changes in effluent limits from the permit issued in 2004.

     Table 18.       Comparison of Effluent Limits
                         Basis of    Previous Effluent Limits: Puget          Proposed Effluent Limits:
                          Limit            Sound Outfall #001                 Puget Sound Outfall #001
                                         Average          Average            Average           Average
                                         Monthly           Weekly            Monthly            Weekly
     Biochemical        Technology   30 mg/L,           45 mg/L,         30 mg/L,            45 mg/L,
     Oxygen                          36,000 lbs/day,    54,000 lbs/day   36,000 lbs/day,     54,000 lbs/day
     Demand (5-day)                  85% min. removal                    85% min. removal
     Total              Technology   30 mg/L,           45 mg/L,         30 mg/L,            45 mg/L,
     Suspended                       36,000 lbs/day,    54,000 lbs/day   36,000 lbs/day,     54,000 lbs/day
     Solids                          85% min. removal                    85% min. removal
     Fecal Coliform     Technology   200/100 mL         400/100 mL       200/100 mL          400/100 mL
     Bacteria
     pH                 Technology   6.0-9.0            6.0-9.0          6.0-9.0             6.0-9.0
     Total Residual     Technology   0.5 mg/L,          0.75 mg/L 1      0.5 mg/L            0.75 mg/L 1
     Chlorine                        600 lbs/day
                                         Previous Effluent Limits:          Proposed Effluent Limits2:
                                         Green River-Maintenance            Green River-Maintenance
         Parameter                        Average          Maximum           Average         Maximum
                                          Monthly            Daily           Monthly           Daily
     BOD5 daily                      NA                 20 mg/L          NA                20 mg/L
     maximum
     TSS, daily                      NA                 20 mg/L          NA                  20 mg/L
     maximum
     Fecal Coliform                  NA                 200/100 mL       NA                  200/100 mL
     Bacteria,
     daily max.
     pH                              NA                 6.0-9.0          NA                  6.0-9.0
       Parameter                          Average          Maximum            Average          Maximum
                                          Monthly            Daily            Monthly             Daily
     Total Residual                  NA                 171 ug/L         NA                  171 ug/L
     Chlorine
     1
         Represents a Maximum Daily Limit
     2
         No limits are proposed for an emergency discharge to the Green River.
   Fact Sheet for NPDES Permit WA-002958-1                                             Page 46 of 101
   King County South Wastewater Treatment Plant

IV. MONITORING REQUIREMENTS
   Ecology requires monitoring, recording, and reporting (WAC 173-220-210 and 40 CFR 122.41)
   to verify that the treatment process is functioning correctly and that the discharge complies with
   the permit’s effluent limits.
   The monitoring schedule is detailed in the proposed permit under Condition S2. Specified
   monitoring frequencies take into account the quantity and variability of the discharge, the treatment
   method, past compliance, significance of pollutants, and cost of monitoring. The required
   monitoring frequency is consistent with agency guidance given in the current version of Ecology’s
   Permit Writer's Manual (Publication Number 92-09) for an activated sludge secondary treatment
   plant.
   Monitoring of sludge quantity and quality is necessary to determine the appropriate uses of the
   sludge. Biosolids monitoring is required by the current state and local solid waste management
   program and also by EPA under 40 CFR 503.
   As a pretreatment publicly-owned treatment works (POTW), King County is required to sample
   influent, final effluent, and sludge for toxic pollutants in order to characterize the industrial input.
   Sampling is also done to determine if pollutants interfere with the treatment process or pass through
   the plant to the biosolids or the receiving water. King County will use the monitoring data to
   develop local limits which commercial and industrial users must meet.
   The proposed permit requires King County to monitor for sediment toxicity to further characterize
   the sediments near the outfall.

   A. Lab Accreditation
       Ecology requires that facilities must use a laboratory registered or accredited under the
       provisions of Chapter 173-50 WAC, Accreditation of Environmental Laboratories, to prepare
       all monitoring data (with the exception of certain parameters). Ecology accredited the
       laboratory at this facility for General Chemistry and Microbiology. The County’s
       environmental lab at W. Ewing Street is additionally accredited for trace metals by ICP-OES
       and ICP-MS, mercury, inorganics, organics by GC and GC-MS, bioassays, and microbiology in
       matrices, including liquids, sediments, and tissues.
     Fact Sheet for NPDES Permit WA-002958-1                                           Page 47 of 101
     King County South Wastewater Treatment Plant



V.   OTHER PERMIT CONDITIONS
     A. Reporting and Record Keeping

         Ecology based permit Condition S3 on our authority to specify any appropriate reporting and
         record keeping requirements to prevent and control waste discharges (WAC 173-220-210).

     B. Prevention of Facility Overloading
         Overloading of the treatment plant is a violation of the terms and conditions of the permit. To
         prevent this from occurring, RCW 90.48.110 and WAC 173-220-150 require King County to
         take the actions detailed in proposed permit Requirement S4 to plan expansions or
         modifications before existing capacity is reached and to report and correct conditions that could
         result in new or increased discharges of pollutants. Condition S4 restricts the amount of flow.

     C. Operation and Maintenance (O&M)
         The proposed permit contains Condition S.5 as authorized under RCW 90.48.110, WAC
         173-220-150, Chapter 173-230 WAC, and WAC 173-240-080. Ecology included it to ensure
         proper operation and regular maintenance of equipment, and to ensure that King County takes
         adequate safeguards so that it uses constructed facilities to their optimum potential in terms of
         pollutant capture and treatment.

     D. Pretreatment

         Duty to Enforce Discharge Prohibitions
         This provision prohibits the publicly-owned treatment works (POTW) from authorizing or
         permitting an industrial discharger to discharge certain types of waste into the sanitary sewer.
         •   The first section of the pretreatment requirements prohibits the POTW from accepting
             pollutants which causes “pass-through” or “interference.” This general prohibition is
             from 40 CFR §403.5(a). Appendix B of this fact sheet defines these terms.
         •   The second section reinforces a number of specific state and federal pretreatment
             prohibitions found in WAC 173-216-060 and 40 CFR §403.5(b). These reinforce that
             the POTW may not accept certain wastes, which:
              • Are prohibited due to dangerous waste rules.
              • Are explosive or flammable.
              • Have too high or low of a pH (too corrosive, acidic or basic).
              • May cause a blockage such as grease, sand, rocks, or viscous materials.
              • Are hot enough to cause a problem.
              • Are of sufficient strength or volume to interfere with treatment.
              • Contain too much petroleum-based oils, mineral oil, or cutting fluid.
              • Create noxious or toxic gases at any point.
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King County South Wastewater Treatment Plant
         40 CFR Part 403 contains the regulatory basis for these prohibitions, with the exception
         of the pH provisions which are based on WAC 173-216-060.
     •   The third section of pretreatment conditions reflects state prohibitions on the POTW
         accepting certain types of discharges unless the discharge has received prior written
         authorization from Ecology. These discharges include:
          • Cooling water in significant volumes.
          • Stormwater and other direct inflow sources.
          • Wastewaters significantly affecting system hydraulic loading, which do not
              require treatment.
     Ecology delegated authority to King County for permitting, monitoring, and enforcement over
     industrial users discharging to their treatment system to provide more direct and effective
     control of pollutants. Ecology oversees the delegated Industrial Pretreatment Program to
     assure compliance with federal pretreatment regulations (40 CFR Part 403) and categorical
     standards and state regulations (Chapter 90.48 RCW and Chapter 173-216 WAC).

E. Solid Waste Control
     To prevent water quality problems, the facility is required in permit Condition S7 to store
     and handle all residual solids (grit, screenings, scum, sludge, and other solid waste) in
     accordance with the requirements of RCW 90.48.080 and state water quality standards.
     The final use and disposal of sewage sludge from this facility is regulated by U.S. EPA under
     40 CFR 503, and by Ecology under Chapter 70.95J RCW, Chapter 173-308 WAC “Biosolids
     Management,” and Chapter 173-350 WAC “Solid Waste Handling Standards.” The disposal
     of other solid waste is under the jurisdiction of the King County Health Department.

F.   Spill Plan
     This facility stores a quantity of chemicals on-site that have the potential to cause water
     pollution if accidentally released. Ecology can require a facility to develop best
     management plans to prevent this accidental release [Section 402(a)(1) of the Federal Water
     Pollution Control Act (FWPCA) and RCW 90.48.080].
     The proposed permit requires this facility to develop and implement a plan for preventing
     the accidental release of pollutants to state waters and for minimizing damages if such a
     spill occurs.

G. Outfall Evaluation
     The proposed permit requires King County to conduct an outfall inspection and submit a
     report detailing the findings of that inspection (Condition S13). The inspection must
     evaluate the physical condition of the discharge pipe and diffusers, and evaluate the extent
     of sediment accumulations in the vicinity of the outfall.
   Fact Sheet for NPDES Permit WA-002958-1                                         Page 49 of 101
   King County South Wastewater Treatment Plant
   H. General Conditions
       Ecology bases the standardized General Conditions on state and federal law and regulations.
       They are included in all individual municipal NPDES permits issued by Ecology.


VI. PERMIT ISSUANCE PROCEDURES
   A. Permit Modifications
       Ecology may modify this permit to impose numerical limits, if necessary, to comply with
       water quality standards for surface waters, with sediment quality standards, or with water
       quality standards for ground waters, based on new information from sources such as
       inspections, effluent monitoring, outfall studies, and effluent mixing studies.
       Ecology may also modify this permit to comply with new or amended state or federal
       regulations.

   B. Proposed Permit Issuance
       This proposed permit meets all statutory requirements for Ecology to authorize a wastewater
       discharge. The permit includes limits and conditions to protect human health and aquatic
       life, and the beneficial uses of waters of the state of Washington. Ecology proposes to issue
       this permit for a term of five years.
   Fact Sheet for NPDES Permit WA-002958-1                                      Page 50 of 101
   King County South Wastewater Treatment Plant

VII. REFERENCES FOR TEXT AND APPENDICES
   Environmental Protection Agency (EPA)
       1992. National Toxics Rule. Federal Register, V. 57, No. 246, Tuesday, December 22, 1992.
       1991. Technical Support Document for Water Quality-Based Toxics Control. EPA/505/2-90-001.
       1988. Technical Guidance on Supplementary Stream Design Conditions for Steady State
         Modeling. USEPA Office of Water, Washington, D.C.
       1985. Water Quality Assessment: A Screening Procedure for Toxic and Conventional
         Pollutants in Surface and Ground Water. EPA/600/6-85/002a.
       1983. Water Quality Standards Handbook. USEPA Office of Water, Washington, D.C.
   Tsivoglou, E.C., and J.R. Wallace.
       1972. Characterization of Stream Reaeration Capacity. EPA-R3-72-012. (Cited in EPA
         1985 op.cit.)
   Washington State Department of Ecology.

       2006. Permit Writer’s Manual. Publication Number 92-109
         (http://www.ecy.wa.gov/biblio/92109.html)
       Laws and Regulations (http://www.ecy.wa.gov/laws-rules/index.html)
          Permit and Wastewater Related Information
          (http://www.ecy.wa.gov/programs/wq/wastewater/index.html)
   Water Pollution Control Federation.
       1976. Chlorination of Wastewater.
   Wright, R.M., and A.J. McDonnell.
       1979. In-stream Deoxygenation Rate Prediction. Journal Environmental Engineering
         Division, ASCE. 105(EE2). (Cited in EPA 1985 op.cit.)
   Fact Sheet for NPDES Permit WA-002958-1                                            Page 51 of 101
   King County South Wastewater Treatment Plant

APPENDIX A—PUBLIC INVOLVEMENT INFORMATION
   Ecology proposes to reissue a permit to King County’s South WWTP. The permit includes
   wastewater discharge limits and other conditions. This fact sheet describes the facility and
   Ecology’s reasons for requiring permit conditions.
   Ecology placed a Public Notice of Application on April 16, 2009, and April 23, 2009, in The
   Seattle Times to inform the public about the submitted application and to invite comments on the
   reissuance of this permit.
   Ecology placed a Public Notice of Draft on July 31, 2009, in The Seattle Times to inform the
   public and to invite comments on the proposed draft National Pollutant Discharge Elimination
   System permit and fact sheet.
   The notice –
   •   Told where copies of the draft permit and fact sheet were available for public evaluation (a
       local public library, the closest regional or field office, posted on our website).
   •   Offered to provide the documents in an alternate format to accommodate special needs.
   •   Asked people to tell us how well the proposed permit would protect the receiving water.
   •   Invited people to suggest fairer conditions, limits, and requirements for the permit.
   •   Invited comments on Ecology’s determination of compliance with antidegradation rules.
   •   Urged people to submit their comments, in writing, before the end of the comment period.
   •   Explained the next step(s) in the permitting process.
   Ecology held an informal public meeting and a formal hearing on September 3, 2009, at King
   County’s regional Bellevue Library to obtain additional comments regarding the South WWTP
   NPDES Permit.
   Ecology has published a document entitled Frequently Asked Questions about Effective Public
   Commenting which is available on our website at http://www.ecy.wa.gov/biblio/0307023.html.
   You may obtain further information from Ecology by telephone, 425-649-7201, or by writing to
   the address listed below.
                                Water Quality Permit Coordinator
                                Department of Ecology
                                Northwest Regional Office
                                3190 160th Avenue SE
                                Bellevue, WA 98008-5452
   The author of this permit and fact sheet is Mark Henley, P.E.
   Fact Sheet for NPDES Permit WA-002958-1                                         Page 52 of 101
   King County South Wastewater Treatment Plant

APPENDIX B—GLOSSARY
   1-DMax or 1-day maximum temperature—The highest water temperature reached on any
      given day. This measure can be obtained using calibrated maximum/minimum thermometers
      or continuous monitoring probes having sampling intervals of thirty minutes or less.
   7-DADMax or 7-day average of the daily maximum temperatures—The arithmetic average
      of seven consecutive measures of daily maximum temperatures. The 7-DADMax for any
      individual day is calculated by averaging that day's daily maximum temperature with the
      daily maximum temperatures of the three days prior and the three days after that date.
   Acute Toxicity—The lethal effect of a compound on an organism that occurs in a short period of
      time, usually 48 to 96 hours.
   AKART—The acronym for “all known, available, and reasonable methods of prevention, control
     and treatment.” AKART is a technology-based approach to limiting pollutants from
     wastewater discharges which requires an engineering judgment and an economic judgment.
     AKART must be applied to all wastes and contaminants prior to entry into waters of the state
     in accordance with RCW 90.48.010 and 520, WAC 173-200-030(2)(c)(ii), and WAC
     173-216-110(1)(a).
   Ambient Water Quality—The existing environmental condition of the water in a receiving
     water body.
   Ammonia—Ammonia is produced by the breakdown of nitrogenous materials in wastewater.
     Ammonia is toxic to aquatic organisms, exerts an oxygen demand, and contributes to
     eutrophication. It also increases the amount of chlorine needed to disinfect wastewater.
   Annual Average Design Flow (AADF)—The average of the daily flow volumes anticipated to
     occur over a calendar year.
   Average Monthly Discharge Limit—The average of the measured values obtained over a
      calendar month's time.
   Best Management Practices (BMPs)—Schedules of activities, prohibitions of practices,
      maintenance procedures, and other physical, structural and/or managerial practices to prevent
      or reduce the pollution of waters of the state. BMPs include treatment systems, operating
      procedures, and practices to control plant site runoff, spillage or leaks, sludge or waste
      disposal, or drainage from raw material storage. BMPs may be further categorized as
      operational, source control, erosion and sediment control, and treatment BMPs.
   BOD5—Determining the Biochemical Oxygen Demand of an effluent is an indirect way of
     measuring the quantity of organic material present in an effluent that is utilized by bacteria.
     The BOD5 is used in modeling to measure the reduction of dissolved oxygen in receiving
     waters after effluent is discharged. Stress caused by reduced dissolved oxygen levels makes
     organisms less competitive and less able to sustain their species in the aquatic environment.
     Although BOD is not a specific compound, it is defined as a conventional pollutant under the
     federal Clean Water Act.
   Bypass—The intentional diversion of waste streams from any portion of a treatment facility.
   Chlorine—Chlorine is used to disinfect wastewaters of pathogens harmful to human health. It is
      also extremely toxic to aquatic life.
Fact Sheet for NPDES Permit WA-002958-1                                          Page 53 of 101
King County South Wastewater Treatment Plant
Chronic Toxicity—The effect of a compound on an organism over a relatively long time, often
   1/10 of an organism's lifespan or more. Chronic toxicity can measure survival, reproduction
   or growth rates, or other parameters to measure the toxic effects of a compound or
   combination of compounds.
Clean Water Act (CWA)—The Federal Water Pollution Control Act enacted by Public Law
   92-500, as amended by Public Laws 95-217, 95-576, 96-483, 97-117; USC 1251 et seq.
Compliance Inspection - Without Sampling—A site visit for the purpose of determining the
  compliance of a facility with the terms and conditions of its permit or with applicable statutes
  and regulations.
Compliance Inspection - With Sampling—A site visit for the purpose of determining the
  compliance of a facility with the terms and conditions of its permit or with applicable statutes
  and regulations. In addition it includes as a minimum, sampling and analysis for all
  parameters with limits in the permit to ascertain compliance with those limits; and, for
  municipal facilities, sampling of influent to ascertain compliance with the 85 percent removal
  requirement. Ecology may conduct additional sampling.
Composite Sample—A mixture of grab samples collected at the same sampling point at
  different times, formed either by continuous sampling or by mixing discrete samples. May
  be "time-composite" (collected at constant time intervals) or "flow-proportional" (collected
  either as a constant sample volume at time intervals proportional to stream flow, or collected
  by increasing the volume of each aliquot as the flow increased while maintaining a constant
  time interval between the aliquots).
Construction Activity—Clearing, grading, excavation, and any other activity which disturbs the
  surface of the land. Such activities may include road building; construction of residential
  houses, office buildings, or industrial buildings; and demolition activity.
Continuous Monitoring—Uninterrupted, unless otherwise noted in the permit.
Critical Condition—The time during which the combination of receiving water and waste
   discharge conditions have the highest potential for causing toxicity in the receiving water
   environment. This situation usually occurs when the flow within a water body is low, thus,
   its ability to dilute effluent is reduced.
Dilution Factor (DF)—A measure of the amount of mixing of effluent and receiving water that
   occurs at the boundary of the mixing zone. Expressed as the inverse of the percent effluent
   fraction, for example, a dilution factor of 10 means the effluent comprises 10% by volume
   and the receiving water 90%.
Engineering Report—A document which thoroughly examines the engineering and
   administrative aspects of a particular domestic or industrial wastewater facility. The report
   must contain the appropriate information required in WAC 173-240-060 or 173-240-130.
Fecal Coliform Bacteria—Fecal coliform bacteria are used as indicators of pathogenic bacteria
   in the effluent that are harmful to humans. Pathogenic bacteria in wastewater discharges are
   controlled by disinfecting the wastewater. The presence of high numbers of fecal coliform
   bacteria in a water body can indicate the recent release of untreated wastewater and/or the
   presence of animal feces.
Fact Sheet for NPDES Permit WA-002958-1                                         Page 54 of 101
King County South Wastewater Treatment Plant
Grab Sample—A single sample or measurement taken at a specific time or over as short a
   period of time as is feasible.
Industrial Wastewater—Water or liquid-carried waste from industrial or commercial processes,
   as distinct from domestic wastewater. These wastes may result from any process or activity
   of industry, manufacture, trade or business; from the development of any natural resource; or
   from animal operations such as feed lots, poultry houses, or dairies. The term includes
   contaminated storm water and, also, leachate from solid waste facilities.
Major Facility—A facility discharging to surface water with an EPA rating score of > 80 points
  based on such factors as flow volume, toxic pollutant potential, and public health impact.
Maximum Daily Discharge Limit—The highest allowable daily discharge of a pollutant
  measured during a calendar day or any 24-hour period that reasonably represents the calendar
  day for purposes of sampling. The daily discharge is calculated as the average measurement
  of the pollutant over the day.
Maximum Day Design Flow (MDDF)—The largest volume of flow anticipated to occur during
  a one-day period, expressed as a daily average.
Maximum Month Design Flow (MMDF)—The largest volume of flow anticipated to occur
  during a continuous 30-day period, expressed as a daily average.
Maximum Week Design Flow (MWDF)—The largest volume of flow anticipated to occur
  during a continuous 7-day period, expressed as a daily average.
Method Detection Level (MDL)—The minimum concentration of a substance that can be
  measured and reported with 99 percent confidence that the pollutant concentration is above
  zero and is determined from analysis of a sample in a given matrix containing the pollutant.
Minor Facility—A facility discharging to surface water with an EPA rating score of < 80 points
  based on such factors as flow volume, toxic pollutant potential, and public health impact.
Mixing Zone—An area that surrounds an effluent discharge within which water quality criteria
   may be exceeded. The area of the authorized mixing zone is specified in a facility's permit
   and follows procedures outlined in state regulations (Chapter 173-201A WAC).
National Pollutant Discharge Elimination System (NPDES)—The NPDES (Section 402 of
   the Clean Water Act) is the federal wastewater permitting system for discharges to navigable
   waters of the United States. Many states, including the state of Washington, have been
   delegated the authority to issue these permits. NPDES permits issued by Washington State
   permit writers are joint NPDES/State permits issued under both state and federal laws.
pH—The pH of a liquid measures its acidity or alkalinity. It is the negative logarithm of the
  hydrogen ion concentration. A pH of 7 is defined as neutral, and large variations above or
  below this value are considered harmful to most aquatic life.
Peak Hour Design Flow (PHDF)—The largest volume of flow anticipated to occur during a
   one-hour period, expressed as a daily or hourly average.
Peak Instantaneous Design Flow (PIDF)—The maximum anticipated instantaneous flow.
Fact Sheet for NPDES Permit WA-002958-1                                          Page 55 of 101
King County South Wastewater Treatment Plant
Quantitation Level (QL)—The smallest detectable concentration of analyte greater than the
  Method Detection Limit (MDL) where the accuracy (precision &bias) achieves the
  objectives of the intended purpose.
Reasonable Potential—A reasonable potential to cause a water quality violation, or loss of
   sensitive and/or important habitat.
Responsible Corporate Officer—A president, secretary, treasurer, or vice-president of the
   corporation in charge of a principal business function, or any other person who performs
   similar policy- or decision-making functions for the corporation, or the manager of one or
   more manufacturing, production, or operating facilities employing more than 250 persons or
   have gross annual sales or expenditures exceeding $25 million (in second quarter 1980
   dollars), if authority to sign documents has been assigned or delegated to the manager in
   accordance with corporate procedures (40 CFR 122.22).
Technology-Based Effluent Limit—A permit limit that is based on the ability of a treatment
   method to reduce the pollutant.
Total Suspended Solids (TSS)—Total suspended solids is the particulate material in an effluent.
   Large quantities of TSS discharged to receiving waters may result in solids accumulation.
   Apart from any toxic effects attributable to substances leached out by water, suspended solids
   may kill fish, shellfish, and other aquatic organisms by causing abrasive injuries and by
   clogging the gills and respiratory passages of various aquatic fauna. Indirectly, suspended
   solids can screen out light and can promote and maintain the development of noxious
   conditions through oxygen depletion.
Solid Waste—All putrescible and non-putrescible solid and semisolid wastes including, but not
    limited to, garbage, rubbish, ashes, industrial wastes, swill, sewage sludge, demolition and
    construction wastes, abandoned vehicles or parts thereof, contaminated soils and
    contaminated dredged material, and recyclable materials.
State Waters—Lakes, rivers, ponds, streams, inland waters, underground waters, salt waters,
   and all other surface waters and watercourses within the jurisdiction of the state of
   Washington.
Stormwater—That portion of precipitation that does not naturally percolate into the ground or
   evaporate, but flows via overland flow, interflow, pipes, and other features of a storm water
   drainage system into a defined surface water body, or a constructed infiltration facility.
Upset—An exceptional incident in which there is unintentional and temporary noncompliance
   with technology-based permit effluent limits because of factors beyond the reasonable
   control of the Permittee. An upset does not include noncompliance to the extent caused by
   operational error, improperly designed treatment facilities, lack of preventative maintenance,
   or careless or improper operation.
Water Quality-Based Effluent Limit—A limit on the concentration of an effluent parameter
  that is intended to prevent the concentration of that parameter from exceeding its water
  quality criterion after it is discharged into receiving waters.
   Fact Sheet for NPDES Permit WA-002958-1                                                                                     Page 56 of 101
   King County South Wastewater Treatment Plant



APPENDIX C—SOUTH WWTP APPLICATION PRIORITY POLLUTANT DATA SUMMARY

                                     MAXIMUM DAILY                         AVERAGE DAILY DISCHARGE
                                      DISCHARGE                                                                            ANALYTICAL
      POLLUTANT              Conc.      Units     Mass       Units     Conc.     Units     Mass       Units      Number     METHOD
                                                                                                                                           ML/MDL
                                                                                                                   of
                                                                                                                 Samples
    METALS (TOTAL RECOVERABLE), CYANIDE, PHENOLS, AND HARDNESS.

    ANTIMONY                  0.67      µg/L       0.45      lbs/d    <0.51      µg/L      <0.30      lbs/d        32       EPA200.8         0.5

    ARSENIC                   1.60      µg/L       1.17      lbs/d     1.26      µg/L       0.76      lbs/d        34       EPA200.8         0.5

    BERYLLIUM                <MDL       µg/L      <0.18      lbs/d    <MDL        µg/L     <0.12      lbs/d        32       EPA200.8         0.2

    CADMIUM                   0.30      µg/L       0.17      lbs/d    <0.11      µg/L      <0.064     lbs/d        32       EPA200.8         0.1

    CHROMIUM                  4.07      µg/L       2.28      lbs/d     0.87      µg/L       0.51      lbs/d        32       EPA200.8         0.4

    COPPER                   42.40      µg/L      24.01      lbs/d     16.5      µg/L       9.51      lbs/d        32       EPA200.8         0.4

    LEAD                      2.00      µg/L       1.12      lbs/d     0.66      µg/L       0.38      lbs/d        32       EPA200.8         0.2

    MERCURY                                                                                                                  CVAA
                             0.058      µg/L      0.045      lbs/d    <0.05      µg/L      <0.03      lbs/d        33                       0.05
                                                                                                                            EPA245.1

    NICKEL                    4.45      µg/L       2.34      lbs/d     2.99      µg/L       1.78      lbs/d        33       EPA200.8         0.3

    SELENIUM                 <MDL       µg/L      <1.35      lbs/d    <MDL       µg/L      <0.89      lbs/d        33       EPA200.8         1.5

    SILVER                    0.84      µg/L       0.48      lbs/d    <0.35      µg/L      <0.21      lbs/d        32       EPA200.8         0.2

    THALLIUM                 <MDL       µg/L       0.18      lbs/d    <MDL       µg/L      <0.117     lbs/d        33       EPA200.8       0.04-0.2

    ZINC                      68.0      µg/L       38.5      lbs/d     29.0      µg/L       17.4      lbs/d        33       EPA200.8         0.5

    CYANIDE                  0.028      mg/L      14.61      lbs/d    <0.008     mg/L      <5.09      lbs/d        33      SM4500-CN-I,E    0.005

    TOTAL PHENOLIC                                                                                                         EPA 420.1 &      0.005-
    COMPOUNDS                0.080      mg/L       47.2      lbs/d    <0.011     mg/L      <6.55      lbs/d        24
                                                                                                                             420.2           0.02

    HARDNESS (AS                                  105,50
    CaCO3)
                              99.4      mg/L        0
                                                             lbs/d     64.8      mg/L      44,632     lbs/d        75       SM2340C          0.1

    Use this space (or a separate sheet) to provide information on other metals requested by the permit writer
Fact Sheet for NPDES Permit WA-002958-1                                                              Page 57 of 101
King County South Wastewater Treatment Plant
                            MAXIMUM DAILY                 AVERAGE DAILY DISCHARGE
                             DISCHARGE                                                            ANALYTICAL
  POLLUTANT         Conc.     Units   Mass     Units   Conc.   Units   Mass     Units   Number     METHOD
                                                                                                               ML/MDL
                                                                                          of
                                                                                        Samples
 VOLATILE ORGANIC COMPOUNDS

 ACROLEIN           <MDL      µg/L    <3.886   lbs/d   <MDL    µg/L    <2.902   lbs/d     23       EPA 624       5

 ACRYLONITRILE      <MDL      µg/L    <3.886   lbs/d   <MDL    µg/L    <2.902   lbs/d     23       EPA 624       5

 BENZENE            <MDL      µg/L    <0.777   lbs/d   <MDL    ug/L    <0.580   lbs/d     23       EPA 624       1

 BROMOFORM          <MDL      µg/L    <0.777   lbs/d   <MDL    ug/L    <0.580   lbs/d     23       EPA 624       1

 CARBON
 TETRACHLORIDE
                    <MDL      µg/L    <0.777   lbs/d   <MDL    ug/L    <0.580   lbs/d     23       EPA 624       1

 COLORBENZENE       <MDL      µg/L    <0.777   lbs/d   <MDL    µg/L    <0.580   lbs/d     23       EPA 624       1
 CHLOROBIDBROMO-
 METHANE
                    <MDL      µg/L    <0.777   lbs/d   <MDL    µg/L    <0.58    lbs/d     23       EPA 624       1

 CHLOROETHANE       <MDL      µg/L    <0.777   lbs/d   <MDL    µg/L    <0.580   lbs/d     23       EPA 624       1
 2-CHLORO-
 ETHYLVINYL ETHER
                    <MDL      µg/L    <0.777   lbs/d   <MDL    µg/L    <0.580   lbs/d     23       EPA 624       1

 CHOLOROFORM        2.18      µg/L    1.565    lbs/d   <1.32   µg/L    <0.802   lbs/d     23       EPA 624      1.32

 DICHLOROBROMO-
 METHANE
                    <MDL      µg/L    <0.777   lbs/d   <MDL    µg/L    <0.58    lbs/d     23       EPA 624       1

 1,1-
 DICHLOROETHANE
                    <MDL      ug/L    <0.777   lbs/d   <MDL    ug/L    <0.580   lbs/d     23       EPA 624       1

 TRANS-1,2-
 DICHLORO-          <MDL      ug/L    <0.777   lbs/d   <MDL    ug/L    <0.580   lbs/d     23       EPA 624       1
 ETHYLENE

 1,1-
 DICHLOROPROPANE
                    <MDL      µg/L    <0.777   lbs/d   <MDL    µg/L    <0.58    lbs/d     23       EPA 624       1

 ETHYLBENZENE       <MDL      ug/L    <0.777   lbs/d   <MDL    ug/L    <0.58    lbs/d     23       EPA 624       1

 METHYL BROMIDE     <MDL      ug/L    <3.49    lbs/d   <MDL    ug/L    <1.92    lbs/d     23       EPA 624       5

 METHYL
 CHLORIDE
                    <MDL      ug/L    <0.78    lbs/d   <MDL    ug/L    <0.58    lbs/d     23       EPA 624       1

 METHYLENE
 CHLORIDE
                     7        ug/L    4.164    lbs/d   <4.74   ug/L    <2.74    lbs/d     23       EPA 624       5

 1,1,2,2-
 TETRACHLORO-       <MDL      ug/L    <0.777   lbs/d   <MDL    ug/L    <0.580   lbs/d     23       EPA 624       1
 ETHANE

 TETRACHLORO-
 ETHYLENE
                    <MDL      µg/L    <0.777   lbs/d   <MDL    µg/L    <0.58    lbs/d     23       EPA 624       1

 TOLUENE            3.86      ug/L    1.845    lbs/d   <1.45   ug/L    <0.78    lbs/d     23       EPA 624       4
Fact Sheet for NPDES Permit WA-002958-1                                                                                     Page 58 of 101
King County South Wastewater Treatment Plant
                                  MAXIMUM DAILY                         AVERAGE DAILY DISCHARGE
                                   DISCHARGE                                                                            ANALYTICAL
   POLLUTANT              Conc.      Units     Mass       Units     Conc.     Units     Mass       Units      Number     METHOD
                                                                                                                                     ML/MDL
                                                                                                                of
                                                                                                              Samples
 1,1,1-
 TRICHLOROETHANE
                          <MDL       ug/L      <0.777     lbs/d    <MDL       ug/L      <0.580     lbs/d        23       EPA 624        1

 1,1,2-
 TRICHLOROETHANE
                          <MDL       ug/L      <0.777     lbs/d    <MDL       ug/L      <0.580     lbs/d        23       EPA 624        1

 TRICHLOROETHYL
 ENE
                          <MDL       ug/L      <0.777     lbs/d    <MDL       ug/L      <0.580     lbs/d        23       EPA 624        1

 VINYL CHLORIDE           <MDL       ug/L      <0.777     lbs/d    <MDL       ug/L      <0.580     lbs/d        23       EPA 624        1
 Use this space (or a separate sheet) to provide information on other metals requested by the permit writer



 ACID-EXTRACTABLE COMPOUNDS

 P-CHLORO-M-                                                                                                                EPA
 CRESOL                   <MDL       µg/L      <1.48      lbs/d    <MDL       µg/L      <1.14      lbs/d        24                    1.9-2.4
                                                                                                                         3520C/625

 2-CHLOROPHENOL                                                                                                             EPA
                          <MDL       µg/L      <1.48      lbs/d    <MDL       µg/L      <1.14      lbs/d        24                    1.9-2.4
                                                                                                                         3520C/625

 2,4-                                                                                                                       EPA
 DIMETHYLPHENOL           <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.56      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625

 4,6-DINITRO-O-                                                                                                             EPA
 CRESOL                   <MDL       µg/L      <1.48      lbs/d    <MDL       µg/L      <1.14      lbs/d        24                    1.9-2.4
                                                                                                                         3520C/625

 2,4-                                                                                                                       EPA
 DINITROPHENOL            <MDL       µg/L      <1.48      lbs/d    <MDL       µg/L      <1.14      lbs/d        24                    1.9-2.4
                                                                                                                         3520C/625

 2-NITROPHENOL                                                                                                              EPA
                          <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.56      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625

 4-NITROPHENOL                                                                                                              EPA
                          <MDL       µg/L      <1.48      lbs/d    <MDL       µg/L      <1.14      lbs/d        24                    1.9-2.4
                                                                                                                         3520C/625
 PENTA                                                                                                                      EPA
 CHLOROPHENOL             <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.56      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625

 PHENOL                                                                                                                     EPA
                          <MDL       µg/L      <2.95      lbs/d    <MDL       µg/L      <2.27      lbs/d        24                      3.9
                                                                                                                         3520C/625

 2,4,6-TRICHLORO                                                                                                            EPA
 PHENOL                   <MDL       µg/L      <2.95      lbs/d    <MDL       µg/L      <2.27      lbs/d        24                    3.8-4.7
                                                                                                                         3520C/625
 Use this space (or a separate sheet) to provide information on other metals requested by the permit writer



 BASE-NEUTRAL COMPOUNDS

 ACENAPHTHENE                                                                                                               EPA
                          <MDL       µg/L      <0.30      lbs/d    <MDL       µg/L      <0.23      lbs/d        24                   0.38-0.47
                                                                                                                         3520C/625

 ACENAPHTYLENE                                                                                                              EPA
                          <MDL       µg/L      <0.44      lbs/d    <MDL       µg/L      <0.34      lbs/d        24                   0.57-0.71
                                                                                                                         3520C/625

 ANTHRACENE                                                                                                                 EPA
                          <MDL       µg/L      <0.44      lbs/d    <MDL       µg/L      <0.34      lbs/d        24                   0.57-0.71
                                                                                                                         3520C/625

 BENZIDINE                                                                                                                  EPA
                          <MDL       µg/L      <17.88     lbs/d    <MDL       µg/L      <13.72     lbs/d        24                    23-28
                                                                                                                         3520C/625
 BENZO(A)                                                                                                                   EPA
 ANTHRACENE               <MDL       µg/L      <0.44      lbs/d    <MDL       µg/L      <0.34      lbs/d        24                   0.57-0.71
                                                                                                                         3520C/625
Fact Sheet for NPDES Permit WA-002958-1                                                                                    Page 59 of 101
King County South Wastewater Treatment Plant
                                  MAXIMUM DAILY                         AVERAGE DAILY DISCHARGE
                                   DISCHARGE                                                                            ANALYTICAL
   POLLUTANT              Conc.      Units     Mass       Units     Conc.     Units     Mass       Units      Number     METHOD
                                                                                                                                     ML/MDL
                                                                                                                of
                                                                                                              Samples
 FLUORANTHENE                                                                                                               EPA
                          <MDL       µg/L      <0.44      lbs/d    <MDL       µg/L      <0.34      lbs/d        24                   0.57-0.71
                                                                                                                         3520C/625
 FLUORENE                                                                                                                   EPA
                          <MDL       µg/L      <0.44      lbs/d    <MDL       µg/L      <0.34      lbs/d        24                   0.57-0.71
                                                                                                                         3520C/625
 HEXACHLORO                                                                                                                 EPA
 BENZENE                  <MDL       µg/L      <0.44      lbs/d    <MDL       µg/L      <0.34      lbs/d        24                   0.57-0.71
                                                                                                                         3520C/625
 HEXACHLOROBUT                                                                                                              EPA
 ADIENE                   <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.57      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625
 HEXACHLOROCYCLO-                                                                                                           EPA
 PENTADIENE               <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.57      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625
 HEXA                                                                                                                       EPA
 CHLOROETHANE             <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.57      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625
 INDENO(1,2,3-CD)                                                                                                           EPA
 PYRENE                   <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.57      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625
 ISOPHORONE                                                                                                                 EPA
                          <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.57      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625

 NAPHTHALENE                                                                                                                EPA
                          <MDL       µg/L      <1.17      lbs/d    <MDL       µg/L      <0.90      lbs/d        24                    1.5-1.9
                                                                                                                         3520C/625

 NITROBENZENE                                                                                                               EPA
                          <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.57      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625
 N-NITROSODI-N-                                                                                                             EPA
 PROPYLAMINE              <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.57      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625
 N-NITROSODI-                                                                                                               EPA
 METHYLAMINE              <MDL       µg/L      <2.95      lbs/d    <MDL       µg/L      <2.72      lbs/d        24                    3.8-4.7
                                                                                                                         3520C/625
 N-NITROSODI-                                                                                                               EPA
 PHENYLAMINE              <MDL       µg/L      <0.74      lbs/d    <MDL       µg/L      <0.97      lbs/d        24                   0.94-1.2
                                                                                                                         3520C/625
 PHENANTHRENE                                                                                                               EPA
                          <MDL       µg/L      <0.44      lbs/d    <MDL       µg/L      <0.34      lbs/d        24                   0.57-0.71
                                                                                                                         3520C/625

 PYRENE                                                                                                                     EPA
                          <MDL       µg/L      <0.44      lbs/d    <MDL       µg/L      <0.34      lbs/d        24                   0.57-0.71
                                                                                                                         3520C/625
 1,2,4-                                                                                                                     EPA
 TRICHLOROBENZENE         <MDL       µg/L      <0.44      lbs/d    <MDL       µg/L      <0.44      lbs/d        24                   0.57-0.71
                                                                                                                         3520C/625
 Use this space (or a separate sheet) to provide information on other metals requested by the permit writer



 Use this space (or a separate sheet) to provide information on other metals requested by the permit writer
   Fact Sheet for NPDES Permit WA-002958-1                  Page 60 of 101
   King County South Wastewater Treatment Plant



APPENDIX D—SOUTH WWTP DISCHARGE MONITORING REPORT SUMMARY TABLES

   Discharge Monitoring Data – October 2004 to April 2009
Fact Sheet for NPDES Permit WA-002958-1                                                                                         Page 61 of 101
King County South Wastewater Treatment Plant
                                                            Influent




                BOD, mg/L

                             BOD, mg/L




                                                                         TSS, mg/L



                                                                                      TSS, mg/L
                                             BOD, ppd



                                                            BOD, ppd




                                                                                                      TSS, ppd



                                                                                                                     TSS, ppd
     Date
             Mnthly         Max           Mnthly                       Mnthly                      Mnthly
               Ave          day             Ave         Max day          Ave Max Day                 Ave         Max day
  1-Oct-04    205           213          115655         123429          231          259          132103 152714
 1-Nov-04     217           237          141967         153571          286          300          186667 2000714
 1-Dec-04     209           245          157385         166000          277          297          207933 222000
 1-Jan-05     236           288          167407         184000          289          351          207500 224000
 1-Feb-05     258           293          163100          18000          238          261          150929 179000
 1-Mar-05     257           301          167458         182000          251          293          161700 181000
  1-Apr-05    217           275          144286         172000          234          247          157310 164000
 1-May-05     208           217          123214         131000          248          261          146069 165000
 1-Jun-05     271           289          155267         165000          284          307          162800 172000
  1-Jul-05    266           285          140500          15100          293          308          154710 162000
 1-Aug-05     259           284          133586         147000          255          295          131194   15000
 1-Sep-05     217           231          111000         117000          243          266          123862 139000
  1-Oct-05    203           238          104083         125000          241          276          124500 145000
 1-Nov-05     195           217          130737         142000          228          242          155519 175000
 1-Dec-05     178           207          121667         128000          213          251          153484 173000
 1-Jan-06     106           134          114095         120000          145          163          157033 167000
 1-Feb-06     149           191          117684         125000          195          217          149808 160000
 1-Mar-06     166           179          113789         121000          197          212          134310 145000
  1-Apr-06    131           150           73125          87000          210          246          114733 126000
 1-May-06     178           200           88643          98000          234          274          117600 135000
 1-Jun-06     159           184           88517         101000          251          292          139533 159000
  1-Jul-06    167           179           82161          88000          233          241          114839 123000
 1-Aug-06     171            18           77750          85000          234          263          107033 121000
 1-Sep-06     163           187           76400          90000          239          258          112615 121000
  1-Oct-06    183           203           91037         108000          271          302          135000 161000
 1-Nov-06     119           176          115760         128000          198          299          190667 209000
 1-Dec-06     125           154          114791         130000          188          211          170516 185000
 1-Jan-07     194           254          171936         207273          202          234          181675 194047
 1-Feb-07     228           260          175349         189959          214          258          163499 188819
 1-Mar-07     200           222          173264         188278          190          210          163790 172649
  1-Apr-07    223           248          161646         177289          236          300          171296 217415
 1-May-07     261           291          169684         183530          284          314          184373 206998
 1-Jun-07     266           305          155759         185908          280          302          163794 184306
  1-Jul-07    266           281          154919         165367          274          288          159404 162066
 1-Aug-07     267           304          150752         178668          279          297          157276 174574
 1-Sep-07     258           287          143860         157492          265          279          149373 159556
  1-Oct-07    245           286          153475         181750          248          306          155068 193760
 1-Nov-07     251           258          167336         175401          252          287          166792 195538
 1-Dec-07     208           233          187630         212502          205          218          183212 197848
 1-Jan-08     230           253          185376         194462          222          255          179970 207100
 1-Feb-08     246           261          180033         182851          234          255          172707 179393
 1-Mar-08     251           276          195478         206004          248          265          190174 196611
  1-Apr-08    250           275          173840         187373          249          258          176737 187316
 1-May-08     272           285          155043         164240          280          304          160027 174982
 1-Jun-08     270           317          157417         175848          267          300          156557 166613
  1-Jul-08    291           308          128112         139850          284          309          125001 131251
 1-Aug-08     276           302          132284         146017          263          279          128507 151526
 1-Sep-08     271           287          142891         149496          259          272          136316 141808
  1-Oct-08    285           300          152221         161913          264          292          140785 150531
 1-Nov-08     253           289          178953         191857          257          284          184084 216825
 1-Dec-08     266           305          191900         240824          216          250          155366 173750
 1-Jan-09     252           301          214073         225037          216          233          185616 232900
 1-Feb-09     290           305          196211         207194          260          278          175071 184177
 1-Mar-09     266           302          207950         222730          242          251          189248 191276
  1-Apr-09    242           283          159607         206371          259          348          170167 225204

     AVE:     223           248          144231         152763          243          270 156587 203983
     MIN:     106            18           73125          15100          145          163 107033   15000
     MAX:     291           317          214073         240824          293          351 207933 2000714
     Limit                               251000                                          235000
     85%                                 213350                                          199750
Fact Sheet for NPDES Permit WA-002958-1                                                                                                                                                           Page 62 of 101
King County South Wastewater Treatment Plant
                                                                                                           Effluent




                                                                                                                                                                                                                                   Cal. Cl, ppd
                                           BOD, mg/L


                                                        BOD, mg/L
              Flow, MGD



                            Flow, MGD




                                                                                                           TSS, mg/L


                                                                                                                        TSS, mg/L
                                                                       BOD, ppd


                                                                                     BOD, ppd




                                                                                                                                                                                Coliform,

                                                                                                                                                                                            Coliform,
                                                                                                Removal




                                                                                                                                                                Removal
                                                                                                                                       TSS, ppd


                                                                                                                                                     TSS, ppd
                                                                                                BOD, %




                                                                                                                                                                                                        Cl, mg/L


                                                                                                                                                                                                                    Cl, mg/L
                                                                                                                                                                TSS, %




                                                                                                                                                                                Fecal

                                                                                                                                                                                            Fecal
                                                                                                                                                                          PH

                                                                                                                                                                                PH
    Date
            Mnthly                      Mnthly         Wkly         Mnthly         Wkly Mnthly Mnthly                  Wkly         Mnthly         Wkly Mnthly Day Day                          Ave                Max         Monthly
             Ave Max day                  Ave          Ave            Ave          Ave   Ave    Ave                    Ave           Ave           Ave    Ave Min Max                 GEM GM7 Monthly              day           Ave
 1-Oct-04    67.9          76.9          14.8          15.3          8371          8543            93     13.9         16.1          8013         10143            94       7   9.8    33      80 0.003            0.02           1.5
1-Nov-04      78          106.9           14            15           9117          9800            93      18           20          11910         14300            94       7   8.2   153     208     0            0.01             0
1-Dec-04     91.3         109.6          15.6           17          12074         15100            93      17          20.3         12910         15400            94     6.4   8.9    67      83     0            0.01             3
1-Jan-05      91           118            15            17          11118         13100            94      17           22          12603         15000            94     6.8   8.3   107     320  0.02            0.19           22
1-Feb-05      75            82            16            19          10315         13000            94      21           24          13425         16300            91     6.9   7.5    64      99     0               0             0
1-Mar-05      78           100           20.5          23.5         13483         15180            92     15.4         17.7          9952         11500            94     6.9   7.3    48     206     0               0             0
 1-Apr-05     81            82            15            18          10369         12200            93     13.5          14           9160          9400            94     6.8   8.5    17      22     0               0             0
1-May-05      70            73           10.9           12           6397          7000            95     13.7          18           8100         11000            94     6.8   7.3    37      88     0               0             0
1-Jun-05      68            70            14            18           7787         10000            95     12.5          18           7117          9900            96     6.7   7.2   121     196     0               0             0
 1-Jul-05     63           63.7          20.7           23          10924         12000            92     17.3          19           9126         10100            94     6.8   7.4    75     265     0               0             0
1-Aug-05     61.3          61.9           16            18           8155          9100            94      13           14           6687          7500            95     6.4   7.2   108     148     0               0             0
1-Sep-05      61           62.2           14            17           7155          8600            94     15.8         16.6          8043          8400            93     6.8   7.2    95     180     0               0             0
 1-Oct-05     62           62.4          12.2           13           6321          6700            94     14.7          17           7703          9000            94     6.8   7.3    50      70     0               0             0
1-Nov-05      81           86.2           14            15           8891          9500            93     20.8          22          14030         14900            91     6.9   7.1    59     134     0               0             0
1-Dec-05      91          133.4          14.4           20          10867         21600            92     25.3          36          20645         40500            88     6.6   7.3    54     115     0               0             0
1-Jan-06     133           158           14.7           23          16855         24700            86     20.4          34          23097         36700            86       6   7.3    66     125     0               0             0
1-Feb-06      96           148            11            11           8835         12400            93      14           15          11311         18200            93     6.5     7    48      76     0               0             0
1-Mar-06      81            90           13.8           16           9333         10500            92     16.4         18.4         11090         11900            92     6.6     7   130     329     0            0.01             0
 1-Apr-06     65            78            10           13.7          5720          7900            92     14.2          19           7853         11000            93       6   7.4    88     197  0.01            0.05             3
1-May-06      60            70           14.4           20           7161          9700            92     12.9         14.8          6448          7400            94     6.4   7.8    51      67     0            0.03             2
1-Jun-06      66            77            12            15           6514          8000            93      9.9          11           5480          6200            96     6.5   7.2    86     100     0            0.02             2
 1-Jul-06     59            65           11.9          13.4          5835          6600            93     16.1         18.9          7865          8700            93     6.8   7.1   134     294     0            0.03             0
1-Aug-06      55            58            9.7           11           4426          5000            94     11.7          16           5345          7000            95     6.1   7.5    42     108     0            0.05             2
1-Sep-06      56            62              9           10           4293          4800            94     14.5          17           6803          8300            94     6.6   7.4    79     156     0            0.03             1
 1-Oct-06     59            74           11.4          14.1          5664          7500            94     11.7         13.9          5794          7300            96     6.5   8.6    40      44     0               0             0
1-Nov-06     119           183            15            18          15569         22157            88      30           41          32357         50971            85     6.3     7    56     135     0            0.03             2
1-Dec-06     111           193            14            18          14133         21700            89      23           30          22455         35000            88     6.3   6.9    41      86     0               0             0
1-Jan-07     104          142.7           22            26          18777         21394            89      25           34          22760         36308            87     6.3   7.1   110     249  0.05            0.05          43.5
1-Feb-07     89.1         115.2           20            21          15262         17447            91      17           18          12850         14838            92     6.7   7.2    49     105  0.05            0.05          37.2
1-Mar-07    100.7         131.5           18            19          15154         17003            91      18           21          15494         18647            91     6.6     7    32     116  0.05            0.05           42
 1-Apr-07    82.9          95.8           25            30          16969         20271            89      22           25          15192         16891            91     6.6   8.8    96     300  0.05            0.05          34.6
1-May-07     72.8           81            18            29          10918         19169            94      17           22          10587         13766            94     6.6   7.8    57      85  0.05            0.05          30.4
1-Jun-07     66.5          70.3           18            21          10191         11651            93      13           15           7296          8111            95     6.6   7.2   110     355  0.05            0.05          27.7
 1-Jul-07    67.3          77.2           12            14           6595          8178            96        8            9          4651          5108            97     6.2   6.8    56     173  0.05            0.08          28.6
1-Aug-07     64.7           70            15            19           8072          9890            95      12           15           6430          7847            96     6.5   6.9    85     241  0.06            0.17           30
1-Sep-07     62.7          84.2           15            17           7906          8987            94      16           18           8302          9642            94     6.5   7.2   105     247  0.05            0.14          27.8
 1-Oct-07    70.4          82.8           15            17           9063         10124            94      13           19           7615         11394            95       6   7.3   150     308  0.05            0.05          29.4
1-Nov-07     74.4          95.8           17            21          10934         12993            93      15           21           9411         13286            94     6.6   7.2   170     254  0.05            0.15          34.2
1-Dec-07     99.4         234.9           23            24          19843         29360            90      25           27          21218         32134            89     6.6   7.3   141     363  0.29            0.75         231.3
1-Jan-08     89.7         116.6           22            26          16617         18282            91      24           29          17989         20585            90     6.7   7.2    35      39  0.07            0.17          49.2
1-Feb-08     79.9         104.1           23            28          15193         20311            92      24           30          16590         21710            90     6.7   7.4    35      62  0.05            0.05          33.3
1-Mar-08     81.6         106.5           20            21          13795         15267            93      23           25          15653         18520            92     6.9   7.3    37      78  0.06            0.16          44.8
 1-Apr-08    75.6          89.1           17            22          10405         17768            94      21           28          13513         21306            92       7   7.4   135     259  0.05            0.05          31.5
1-May-08     60.4          65.8           19            21           9811         10519            94      16           18           8214          9073            95     7.1   7.5   106     145  0.05            0.07          25.6
1-Jun-08     62.4          74.2           18            20           9145         10226            94      13           14           6962          8126            95     7.1   7.5    84     171  0.05            0.12           28
 1-Jul-08    45.2          55.1           17            19           6547          7584            95      17           20           6578          8192            95     7.3   7.5    48      66  0.05            0.07          19.1
1-Aug-08     52.1          76.7           17            18           7143          8777            95      15           19           6731          9291            95     7.2   7.5    20      23  0.05            0.07           22
1-Sep-08     57.7          64.6           13            13           6151          6578            96        9          11           4388          4999            97     6.8   8.4    25      43  0.05            0.11          25.1
 1-Oct-08    59.2          65.3           16            25           8188         12753                    16           22           7908         11281                   6.9   7.6    34      53  0.06            0.22          28.7
1-Nov-08     80.5         144.4           22            25          15108         19881                    18           20          12195         15558                   6.8   6.9    85     185  0.06            0.18          39.3
1-Dec-08     81.6         132.6           23            27          15799         21514                    23           26          15517         24360                   6.7   6.9    38      56  0.06            0.17          39.9
1-Jan-09    100.8         200.7           23            26          20186         29891                    27           30          23121         32420                   6.3   6.9    35     104  0.06            0.19          53.4
1-Feb-09     73.5          84.4           19            24          11865         14750                    19           20          11405         13378                   6.5   6.9    23      56  0.05            0.05          30.6
1-Mar-09     87.7         105.8           20            22          14582         18491                    24           30          17672         24443                   6.5   6.8    94     145  0.05            0.05          36.6
 1-Apr-09     75          124.4           18            20          11231         15467                    19           24          11958         16810                   6.3   6.9    43      80  0.05            0.05          31.3

    AVE: 76.34   98.36                     16           19          10665 13545                    93      17           21          11696 15615                    93     6.6   7.4    73     152         0           0             8
    MIN: 45.20   55.10                      9           10           4293 4800                     86       8            9           4388 4999                     85     6.0   6.8    17      22         0           0             0
    MAX: 133.00 234.90                     25           30          20186 29891                    96      30           41          32357 50971                    97     7.3   9.8   170     363         0           0            44
    Limit 144.00                           30           45          36000 54000                    85      30           45          36000 54000                    85     6.0   9.0   200     400       0.5        0.75
    85% 122.40
                  Monthly Average Influent TSS, mg/L
                                                                                                                                       Influent TSS, lbs/day




                       100
                              150
                                     200
                                            250
                                                   300
                                                         350




         0
             50
Oct-04




                                                                                                                              50,000
                                                                                                                                           100,000
                                                                                                                                                     150,000
                                                                                                                                                                   200,000
                                                                                                                                                                                                                           250,000




                                                                                                                          0
Dec-04
Feb-05                                                                                                           Oct-04
Apr-05                                                                                                           Dec-04
Jun-05                                                                                                           Feb-05
Aug-05                                                                                                           Apr-05
Oct-05                                                                                                           Jun-05
Dec-05                                                                                                           Aug-05
Feb-06
                                                                                                                 Oct-05
Apr-06
                                                                                                                 Dec-05
Jun-06
                                                                                                                 Feb-06
Aug-06
                                                                                                                 Apr-06
                                                                                                                                                                                                                                                                                                                                         Fact Sheet for NPDES Permit WA-002958-1




Oct-06
                                                                                                                                                                                                                                     South WWTP – Influent TSS (Mass Basis)




                                                                                                                 Jun-06
Dec-06
                                                                                                                                                                                                                                                                                                                                         King County South Wastewater Treatment Plant




                                                                                                                 Aug-06
Feb-07
                                                                                                                 Oct-06
Apr-07




                                                               South WWTP – Influent TSS (Concentration Basis)
Jun-07                                                                                                           Dec-06

Aug-07                                                                                                           Feb-07

Oct-07                                                                                                           Apr-07

Dec-07                                                                                                           Jun-07
Feb-08                                                                                                           Aug-07
Apr-08                                                                                                           Oct-07
Jun-08                                                                                                           Dec-07
Aug-08                                                                                                           Feb-08
Oct-08                                                                                                           Apr-08
Dec-08                                                                                                           Jun-08
Feb-09                                                                                                           Aug-08
                                                                                                                                                                                                             Monthly Avg




                                                                                                                 Oct-08
                                                                                                                 Dec-08
                                                                                                                                                               100% Design Loading
                                                                                                                                                                                     85% of Design Loading




                                                                                                                 Feb-09
                                                                                                                                                                                                                                                                              APPENDIX E—SOUTH WWTP DISCHARGE MONITORING REPORT GRAPHS




                                                                                                                 Apr-09
                                                                                                                                                                                                                                                                                                                                                                Page 63 of 101
              Monthly Average Influent BOD5, mg/L
                                                                                                                                    Influent BOD5, lbs/day




             50
                   100
                          150
                                 200
                                        250
                                               300
                                                     350




         0
Oct-04




                                                                                                                           50,000
                                                                                                                                      100,000
                                                                                                                                                150,000
                                                                                                                                                          200,000
                                                                                                                                                                                          250,000
                                                                                                                                                                                                                                    300,000




                                                                                                                       0
Dec-04
Feb-05                                                                                                        Oct-04

Apr-05                                                                                                        Dec-04
                                                                                                              Feb-05
Jun-05
                                                                                                              Apr-05
Aug-05
                                                                                                              Jun-05
Oct-05
                                                                                                              Aug-05
Dec-05
                                                                                                              Oct-05
Feb-06
                                                                                                              Dec-05
Apr-06
                                                                                                              Feb-06
Jun-06
                                                                                                                                                                                                                                                                                        Fact Sheet for NPDES Permit WA-002958-1




                                                                                                              Apr-06
                                                                                                                                                                                                                                              South WWTP – Influent BOD5 (Mass Basis)




Aug-06                                                                                                        Jun-06
                                                                                                                                                                                                                                                                                        King County South Wastewater Treatment Plant




Oct-06                                                                                                        Aug-06
Dec-06                                                                                                        Oct-06
                                                                                                              Dec-06

                                                           South WWTP – Influent BOD5 (Concentration Basis)
Feb-07
Apr-07                                                                                                        Feb-07

Jun-07                                                                                                        Apr-07
                                                                                                              Jun-07
Aug-07
                                                                                                              Aug-07
Oct-07
                                                                                                              Oct-07
Dec-07
                                                                                                              Dec-07
Feb-08
                                                                                                              Feb-08
Apr-08
                                                                                                              Apr-08
Jun-08
                                                                                                              Jun-08
Aug-08                                                                                                        Aug-08
                                                                                                                                                                                                                      Monthly Avg




Oct-08                                                                                                        Oct-08
Dec-08                                                                                                        Dec-08
                                                                                                                                                                    100% Design Loading
                                                                                                                                                                                              85% of Design Loading




Feb-09                                                                                                        Feb-09
                                                                                                                                                                                                                                                                                                               Page 64 of 101
Fact Sheet for NPDES Permit WA-002958-1                                                                                                                                                                                                                       Page 65 of 101
King County South Wastewater Treatment Plant
South WWTP – Influent Flow
                             160
                                                                                                                                                                                                                                                       Average Monthly Flow

                             140                                                                                                                                                                                                                       85% of Max Month Flow

                                                                                                                                                                                                                                                       100% of Max Month Flow
                             120
  Flow, MGD
    Influent




                             100


                              80


                              60


                              40


                              20


                               0
                                      Oct-04




                                                                     Apr-05




                                                                                                 Oct-05




                                                                                                                              Apr-06




                                                                                                                                                          Oct-06




                                                                                                                                                                                       Apr-07




                                                                                                                                                                                                                   Oct-07




                                                                                                                                                                                                                                                  Apr-08




                                                                                                                                                                                                                                                                               Oct-08
                                                        Feb-05




                                                                                                                     Feb-06




                                                                                                                                                                              Feb-07




                                                                                                                                                                                                                                         Feb-08




                                                                                                                                                                                                                                                                                                 Feb-09
                                                                              Jun-05




                                                                                                                                       Jun-06




                                                                                                                                                                                                 Jun-07




                                                                                                                                                                                                                                                             Jun-08
                                               Dec-04




                                                                                       Aug-05



                                                                                                          Dec-05




                                                                                                                                                 Aug-06



                                                                                                                                                                   Dec-06




                                                                                                                                                                                                          Aug-07



                                                                                                                                                                                                                                Dec-07




                                                                                                                                                                                                                                                                      Aug-08



                                                                                                                                                                                                                                                                                        Dec-08
South WWTP – Effluent pH
                             9.5
                                                                                                                                                                                                                                                                                        Day Min
                             9.0               permit range: 6.0 - 9.0                                                                                                                                                                                                                  Day Max

                             8.5
   Effluent pH, Std. Units




                             8.0


                             7.5


                             7.0


                             6.5


                             6.0


                             5.5
                                                            Aug-04




                                                                                                                   Sep-05




                                                                                                                                                                                                                            Nov-07




                                                                                                                                                                                                                                                                               Dec-08
                                                                                                                                                                     Oct-06




                                                                                                                                                                                                Apr-07
                                                                                        Feb-05




                                                                                                                                            Mar-06




                                                                                                                                                                                                                                                                                                          Jul-09
                                   Jan-04




                                                                                                                                                                                                                                                    Jun-08
Fact Sheet for NPDES Permit WA-002958-1                                                                                                                                                                                                                                                        Page 66 of 101
King County South Wastewater Treatment Plant
South WWTP – Effluent TSS (Mass Basis)
                         60000


                                                                                                                                                                                                                                                              Monthly Avg
                         50000
                                                                                                                                                                                                                                                              Weekly Avg
                                                                                                                                                                                                                                                              Monthly Avg permit limit

                         40000                                                                                                                                                                                                                                Weekly Avg permit limit
  Effluent TSS, ppd




                         30000



                         20000



                         10000



                                      0
                                                                     Feb-05

                                                                                 Apr-05




                                                                                                                                          Feb-06

                                                                                                                                                     Apr-06




                                                                                                                                                                                                            Feb-07

                                                                                                                                                                                                                       Apr-07




                                                                                                                                                                                                                                                                          Feb-08

                                                                                                                                                                                                                                                                                     Apr-08




                                                                                                                                                                                                                                                                                                                                      Feb-09
                                                         Dec-04




                                                                                                                               Dec-05




                                                                                                                                                                                                 Dec-06




                                                                                                                                                                                                                                                                Dec-07




                                                                                                                                                                                                                                                                                                                             Dec-08
                                                                                             Jun-05

                                                                                                         Aug-05




                                                                                                                                                                Jun-06

                                                                                                                                                                           Aug-06




                                                                                                                                                                                                                                 Jun-07

                                                                                                                                                                                                                                           Aug-07




                                                                                                                                                                                                                                                                                               Jun-08

                                                                                                                                                                                                                                                                                                         Aug-08
                                             Oct-04




                                                                                                                    Oct-05




                                                                                                                                                                                      Oct-06




                                                                                                                                                                                                                                                     Oct-07




                                                                                                                                                                                                                                                                                                                   Oct-08
South WWTP – Effluent TSS (Concentration Basis)

                                 50

                                 45
                                                                                                                                                                                                                                                                                   Monthly Avg
                                 40
                                                                                                                                                                                                                                                                                   Weekly Avg

                                 35                                                                                                                                                                                                                                                Monthly Avg permit limit
                                                                                                                                                                                                                                                                                   Weekly Avg permit limit
            Effluent TSS, mg/L




                                 30

                                 25

                                 20

                                 15

                                 10

                                 5

                                 0
                                                      Dec-04




                                                                                                      Aug-05



                                                                                                                             Dec-05




                                                                                                                                                                         Aug-06



                                                                                                                                                                                               Dec-06




                                                                                                                                                                                                                                          Aug-07



                                                                                                                                                                                                                                                               Dec-07




                                                                                                                                                                                                                                                                                                        Aug-08



                                                                                                                                                                                                                                                                                                                            Dec-08
                                          Oct-04




                                                                              Apr-05




                                                                                                                  Oct-05




                                                                                                                                                   Apr-06




                                                                                                                                                                                    Oct-06




                                                                                                                                                                                                                     Apr-07




                                                                                                                                                                                                                                                    Oct-07




                                                                                                                                                                                                                                                                                    Apr-08




                                                                                                                                                                                                                                                                                                                  Oct-08
                                                                  Feb-05




                                                                                                                                        Feb-06




                                                                                                                                                                                                          Feb-07




                                                                                                                                                                                                                                                                         Feb-08




                                                                                                                                                                                                                                                                                                                                      Feb-09
                                                                                          Jun-05




                                                                                                                                                              Jun-06




                                                                                                                                                                                                                                Jun-07




                                                                                                                                                                                                                                                                                              Jun-08
Fact Sheet for NPDES Permit WA-002958-1                                                                                                                                                                                                                                             Page 67 of 101
King County South Wastewater Treatment Plant


South WWTP – Effluent BOD5 (Mass Basis)
              60000



              50000                                                                                                                                                                                                                                                      Monthly Avg
                                                                                                                                                                                                                                                                         Weekly Avg
                                                                                                                                                                                                                                                                         Monthly Avg permit limit
              40000                                                                                                                                                                                                                                                      Weekly Avg permit limit
  BOD5, ppd
   Effluent




              30000



              20000



              10000



                      0
                                     Dec-04




                                                                           Aug-05



                                                                                                Dec-05




                                                                                                                                               Aug-06



                                                                                                                                                                         Dec-06




                                                                                                                                                                                                                        Aug-07



                                                                                                                                                                                                                                                  Dec-07




                                                                                                                                                                                                                                                                                                Aug-08



                                                                                                                                                                                                                                                                                                                     Dec-08
                            Oct-04




                                                       Apr-05




                                                                                     Oct-05




                                                                                                                       Apr-06




                                                                                                                                                            Oct-06




                                                                                                                                                                                                 Apr-07




                                                                                                                                                                                                                                     Oct-07




                                                                                                                                                                                                                                                                          Apr-08




                                                                                                                                                                                                                                                                                                           Oct-08
                                              Feb-05




                                                                                                           Feb-06




                                                                                                                                                                                       Feb-07




                                                                                                                                                                                                                                                              Feb-08




                                                                                                                                                                                                                                                                                                                               Feb-09
                                                                 Jun-05




                                                                                                                                   Jun-06




                                                                                                                                                                                                           Jun-07




                                                                                                                                                                                                                                                                                     Jun-08
South WWTP – Effluent BOD5 (Concentration Basis)

              50

              45
                                                                                                                                                                                                                                                Monthly Avg
              40                                                                                                                                                                                                                                Weekly Avg
                                                                                                                                                                                                                                                Monthly Avg permit limit
              35
                                                                                                                                                                                                                                                Weekly Avg permit limit
BOD5, mg/L
 Effluent




              30

              25

              20

              15

              10

              5

              0
                            Dec-04




                                                                  Aug-05



                                                                                       Dec-05




                                                                                                                                      Aug-06



                                                                                                                                                                Dec-06




                                                                                                                                                                                                                    Aug-07



                                                                                                                                                                                                                                              Dec-07




                                                                                                                                                                                                                                                                                              Aug-08



                                                                                                                                                                                                                                                                                                                    Dec-08
                   Oct-04




                                              Apr-05




                                                                            Oct-05




                                                                                                              Apr-06




                                                                                                                                                   Oct-06




                                                                                                                                                                                            Apr-07




                                                                                                                                                                                                                                 Oct-07




                                                                                                                                                                                                                                                                       Apr-08




                                                                                                                                                                                                                                                                                                         Oct-08
                                     Feb-05




                                                                                                  Feb-06




                                                                                                                                                                              Feb-07




                                                                                                                                                                                                                                                           Feb-08




                                                                                                                                                                                                                                                                                                                              Feb-09
                                                        Jun-05




                                                                                                                          Jun-06




                                                                                                                                                                                                      Jun-07




                                                                                                                                                                                                                                                                                   Jun-08
Fact Sheet for NPDES Permit WA-002958-1                                                                                                                                                                                                           Page 68 of 101
King County South Wastewater Treatment Plant
South WWTP – Effluent Fecal Coliform Bacteria

                                     450


                                     400

                                                                                                                                                                                                                                                          GEM
                                     350
                                                                                                                                                                                                                                                          GM7
 Effluent Fecal Coliform, #/100 mL




                                                                                                                                                                                                                                                          GEM permit limit
                                     300
                                                                                                                                                                                                                                                          GM7 permit limit

                                     250


                                     200


                                     150


                                     100


                                      50


                                       0
                                                             Feb-05

                                                                      Apr-05




                                                                                                                   Feb-06

                                                                                                                            Apr-06




                                                                                                                                                                         Feb-07

                                                                                                                                                                                  Apr-07




                                                                                                                                                                                                                               Feb-08

                                                                                                                                                                                                                                        Apr-08




                                                                                                                                                                                                                                                                                      Feb-09
                                                    Dec-04




                                                                               Jun-05

                                                                                        Aug-05



                                                                                                          Dec-05




                                                                                                                                     Jun-06

                                                                                                                                              Aug-06



                                                                                                                                                                Dec-06




                                                                                                                                                                                           Jun-07

                                                                                                                                                                                                    Aug-07



                                                                                                                                                                                                                      Dec-07




                                                                                                                                                                                                                                                 Jun-08

                                                                                                                                                                                                                                                           Aug-08



                                                                                                                                                                                                                                                                             Dec-08
                                           Oct-04




                                                                                                 Oct-05




                                                                                                                                                       Oct-06




                                                                                                                                                                                                             Oct-07




                                                                                                                                                                                                                                                                    Oct-08
   Fact Sheet for NPDES Permit WA-002958-1        Page 69 of 101
   King County South Wastewater Treatment Plant

APPENDIX F—OUTFALL DIAGRAMS
Fact Sheet for NPDES Permit WA-002958-1        Page 70 of 101
King County South Wastewater Treatment Plant
Fact Sheet for NPDES Permit WA-002958-1        Page 71 of 101
King County South Wastewater Treatment Plant
Fact Sheet for NPDES Permit WA-002958-1                                                     Page 72 of 101
King County South Wastewater Treatment Plant



   Plan View                                                            2,150 ft

                                                                         665 ft
             Pipe length=10,000 ft. Pipe Dia. = 8 ft.
             Diffuser length = 500 ft. Diffuser Dia. =
             64in. with 168 - 4in. Diameter Ports.
                                                                                                1,650 ft
                                                                                     165 ft




                               Chronic Mixing          Acute Mixing
                               Zone Boundary         Zone Boundary
   Side View


                                                                         665 ft
                  0 ft MLLW




                 -625 ft MLLW



                   South WWTP Marine Outfall Mixing Zones – North Diffuser.           Not to Scale

 Plan View                                                            2,150 ft

                                                                      665 ft
         Pipe length=10,000 ft. Pipe Dia. = 8 ft.
         Diffuser length = 500 ft. Diffuser Dia. =
         64in. with 168 - 4in. Diameter Ports.
                                                                                              1,650 ft
                                                                                   165 ft




                            Chronic Mixing          Acute Mixing
                            Zone Boundary         Zone Boundary
 Side View


                                                                      665 ft
               0 ft MLLW




               -625 ft MLLW



                South WWTP Marine Outfall Mixing Zones – South Diffuser.           Not to Scale
   Fact Sheet for NPDES Permit WA-002958-1                                                                                                Page 73 of 101
   King County South Wastewater Treatment Plant

APPENDIX G—WHOLE EFFLUENT TOXICITY (WET) TESTING RESULTS
   ACUTE TEST
   For Acute toxicity, the performance standard is the median survuval in 100% effluent being equal to or
   greater than 80% and no individual test result showing less than 65% survival in 100% effluent.


   King County South Plant Acute WET Test Results as % Survival in 100% Effluent
    Test Code       Collected      Start Date        Organism             Endpoint              % Survival
   RMAR1177          2/8/2008      2/8/2008     Daphnia pulex         48-hour Survival              75%
   RMAR1178         2/11/2008     2/11/2008     Fathead Minnow        96-hour Survival              88%
   RMAR1210          4/2/2008      4/2/2008     Daphnia pulex         48-hour Survival             100%
   RMAR1208          4/7/2008      4/7/2008     Fathead Minnow        96-hour Survival              78%
   RMAR1298          7/9/2008      7/9/2008     Daphnia pulex         48-hour Survival             100%
   RMAR1296         8/18/2008     8/18/2008     Fathead Minnow        96-hour Survival              85%
   RMAR1327         10/8/2008     10/8/2008     Daphnia pulex         48-hour Survival             100%
   RMAR1325         10/13/2008    10/13/2008    Fathead Minnow        96-hour Survival              93%
                                                                                Median =           90%
   Median survival in 100% effluent = 90%. All Acute WET Tests had greater than 65% survival in 100%
   effluent. Therefore, no Acute WET limit required. Permit requires another effluent characterization for acute
   WET (WAC 173-245).


   CHRONIC TEST
   For Chronic toxicity, the performance standard is no chronic toxicity test demonstrating a statistically
   significant difference in response between the control and a test concentration equal to the acute critical
   effluent concentration (ACEC). For the tests below, the previous ACEC of 0.43% effluent was used.


             King County South Plant Chronic WET Test Results as NOEC/LOEC in % Effluent
    Test Code       Collected      Start Date        Organism             Endpoint                NOEC              LOEC        PMSD
   RMAR1180          2/6/2008       2/6/2008    Atlantic Mysid       7-day Survival                 12.5               25       15.43%
                                                                     Biomass                        0.43              12.5      15.46%
                                                                     Weight                         0.43              12.5      14.99%
   RMAR1179          2/6/2008       2/7/2008    Topsmelt             7-day Survival                 12.5               25       12.80%
                                                                     Biomass                        0.43              12.5      16.27%
                                                                     Weight                         0.43              12.5      11.28%
   RMAR1209          4/2/2008       4/2/2008    Topsmelt             7-day Survival                  25                50       11.96%
                                                                     Biomass                        12.5               25       15.36%
                                                                     Weight                         12.5               25       13.46%
   RMAR1207          4/2/2008       4/2/2008    Atlantic Mysid       7-day Survival                  50               100       11.63%
                                                                     Biomass                        12.5               25       13.90%
                                                                     Weight                         0.43              12.5      12.22%
   RMAR1299          7/9/2008       7/9/2008    Atlantic Mysid       7-day Survival                  50               100       12.88%
                                                                     Biomass                        12.5               25       12.92%
                                                                     Weight                         12.5               25       11.83%
   RMAR1297          7/9/2008       7/9/2008    Topsmelt             7-day Survival                  50               100       14.56%
                                                                     Biomass                         25                50       22.16%
                                                                     Weight                          25                50       18.74%
   RMAR1326         10/8/2008      10/8/2008 Topsmelt                7-day Survival                  50               100        7.29%
                                                                     Biomass                         50               100       20.18%
                                                                     Weight                          50               > 50      18.53%
   RMAR1328         10/8/2008      10/8/2008 Atlantic Mysid          7-day Survival                  50               100       15.90%
                                                                     Biomass                         25                50       15.32%
                                                                     Weight                          25                50       12.41%
   If there is no chronic toxicity at the acute mixing zone boundary, then there is no reasonable potential for chronic toxicity at the
   edge of the chronic mixing zone boundary.
   To review, Ecology compares the Lowest Observed Effects Concentration (LOEC) to the ACEC. If the LOEC is always above the
   ACEC, we can assume that there is no chronic toxicity. Based on the above data, the LOEC is always greater than the ACEC
   (0.43 %). Therefore, no chronic WET limit is needed.

   The proposed permit includes lower (more restrictive) dilution factors than the previous permit. This results in a new ACEC of
   0.54% and CCEC of 0.44%, which will be used in the proposed permit for WET testing.
Fact Sheet for NPDES Permit WA-002958-1                                           Page 74 of 101
King County South Wastewater Treatment Plant

APPENDIX H—TECHNICAL CALCULATIONS
Several of the Excel® spreadsheet tools used to evaluate a discharger’s ability to meet
Washington State water quality standards can be found on Ecology’s homepage at
http://www.ecy.wa.gov/programs/eap/pwspread/pwspread.html.
Fact Sheet for NPDES Permit WA-002958-1                                                                                                                           Page 75 of 101
King County South Wastewater Treatment Plant
         Table H-1: South WWTP – Water Quality Criteria for Detected Pollutants

FACILITY: South Plant WWTP
FILENAME:
RUN DATE:4/17/2009
          M. Henley
PREPARED BY:

Red font = National Toxics Rule (40 CFR 131.36)
Blue font = EPA National Recommended Water Quality Criteria:2002 (EPA 822-R-02-47)
Green font = Other source - see comment
Black font = WAC 173-201A (Nov. 1997)

Input Required Data                                            Units
ENTER RECEIVING WATER TSS (IF                0                 mg/L
IF RECEIVING WATER TSS IS ANNUAL             S
HARDNESS VALUE USED FOR                      99.4              mg/L at CaCO 3
HARDNESS DEPENDENT LIMITS>>>>
* = INSUFFICIENT DATA TO DEVELOP
VALUE PRESENTED IS TH L.O.E.L-

WATER QUALITY CRITERIA (in ug/L unless otherwise noted)
Pollutant Pollutant                     CAS No.       NPDES                     Hardness or  Conversion   Conversion   Priority   Carcinogen   Water Quality       Water Quality     Human Health
Detected                                              Application               pH dependent Factor       Factor       Pollutants              Criteria - Marine - Criteria - Marine Criteria - Marine
input "y"                                             Reference No.                                       Chronic                              Acute               - Chronic

48.70     AMMONIA mg/L                                                                                                 N         N             233                 35
0.67      ANTIMONY (INORGANIC)                       7440360              1M                                           Y         N                                                   4300
1.60      ARSENIC (dissolved)                        7440382              2M                                           Y         Y             69                  36
0.30      CADMIUM                                    7440439              4M 50.0            0.97         0.94         Y         N             42.00               9.3
750.00    CHLORINE (Total Residual)                  7782506                                                           N         N             13                  7.50
2.18      CHLOROFORM                                   67663              11V                                          Y         Y                                                   470
4.07      CHROMIUM(HEX)                             18540300                                                           Y         N             1100                50
42.40     COPPER                                      744058              6M    50.0                                   Y         N             4.80                3.10
28.00     CYANIDE                                      57125             14M                                           Y         N             1.00                1.00              220000
3.93      1,4 DICHLOROBENZENE                         106467             22B                                           Y         N                                                   2600
2.00      LEAD                                       7439921              7M    50.0         0.89                      Y         N             210.00              8.10
7.00      METHYLENE CHLORIDE                           75092             22V                                           Y         Y                                                   1600
0.058     MERCURY                                    7439976              8M                                           Y         N             1.80                0.0250            0.15
4.45      NICKEL                                     7440020              9M    50.0                                   Y         N             74.00               8.20              4600
0.84      SILVER                                     7740224             11M    50.0                                   Y         N             1.90                NA
1.40      TETRACHLOROETHYLENE                         127184             24V                                           Y         Y                                                   8.85
3.86      TOLUENE                                     108883             25V                                           Y         N                                                   200000
68.00     ZINC                                       7440666             13M    50.0                                   Y         N             90.00               81.00
Fact Sheet for NPDES Permit WA-002958-1                                                              Page 76 of 101
King County South Wastewater Treatment Plant
      Table H-2: South WWTP – Ammonia Calculation Spreadsheet

Ammonia Calculation Spreadsheet

Calculation of seawater fraction of un-ionized ammonia
  from Hampson (1977). Un-ionized ammonia criteria for
  salt water are from EPA 440/5-88-004. Revised 19-Oct-93.
                                                                     Facility: South Plant WWTP
                                                                        Permit No: WA-002958-1
INPUT*

1. Temperature, deg C (90th percentile):                                           14.0            Max.

2. pH, (90th percentile):                                                           8.0

3. Salinity, g/Kg (90th percentile):                                               31.1            Max.

OUTPUT

1. Pressure (atm; EPA criteria assumes 1 atm):                                      1.0

2. Molal Ionic Strength (not valid if >0.85):                                      0.640

3. pKa8 at 25 deg C (Whitfield model "B"):                                         9.319

4. Percent of Total Ammonia Present as Unionized:                                 2.066%

5. Unionized ammonia criteria (mg un-ionized NH3 per liter)
   from EPA 440/5-88-004
    Acute:                                                                         0.233
    Chronic:                                                                       0.035

6. Total Ammonia Criteria (mg/L as NH3)
    Acute:                                                                         11.28
    Chronic:                                                                       1.69

7. Total Ammonia Criteria (mg/L as NH3-N)
    Acute:                                                                         9.27           9269.35    ug/L
    Chronic:                                                                       1.39           1392.39    ug/L
* Data from ambient monitoring station LSNT01, South Plant Outfall

fn: TSDCalc10.cls
                                                                                          State Water Quality         Max concentration
                                                                                               Standard                 at edge of...
                                                                                                                                                                                                                                                                                                                                                  Fact Sheet for NPDES Permit WA-002958-1




                                                                                                                                                                              95th %
                                                                                                                                                                              effluent
                                                                                                                                                                                                                                                                                                                                                  King County South Wastewater Treatment Plant




                                                                                                                                                                               conc.
                                         Metal        Metal     Ambient                                                                                                      measured
                                        Criteria     Criteria Concentration                                            Acute       Chronic            Effluent                (metals as                                          Acute Chronic
                                     Translator as Translator   (metals as                                             Mixing      Mixing       LIMIT percentile                 total       Coeff               # of              Dil'n  Dil'n
                                        decimal    as decimal   dissolved)                 Acute        Chronic        Zone         Zone       REQ'D? value                  recoverable)   Variation          samples Multiplier Factor Factor
            Parameter                     Acute          Chronic            ug/L            ug/L          ug/L          ug/L         ug/L                             Pn        ug/L          CV         s        n                               COMMENTS

Ammonia                                                                     11.0            9269          1392         212.55      177.62         NO          0.95   0.997     37500         0.210      0.21     934       1      186     225
ARSENIC (dissolved)                  1.00                                  1.4400           69.0           36.0         1.44        1.44          NO          0.95   0.916     1.516         0.101      0.10     34        1      186     225
CADMIUM                              0.994            0.994                0.0746           42.0           9.3          0.07        0.07          NO          0.95   0.911     0.077         0.756      0.67     32        1      186     225
CHLORINE (Total Residual)                                                                   13.0           7.5          0.27        0.22          NO          0.95   0.998     50.000        0.751      0.67    1553       1      186     225
CHROMIUM(HEX)                        0.993            0.993                0.4510          1100.0          50.0         0.46        0.46          NO          0.95   0.911     1.480         0.723      0.65     32        1      186     225
COPPER                               0.83             0.83                 0.5740            4.8           3.1          0.71        0.69          NO          0.95   0.911     31.340        0.475      0.45     32        1      186     225
CYANIDE                                                                                      1.0           1.0          0.00        0.00          NO          0.95   0.913     0.019         0.903      0.77     33        1      186     225
LEAD                                 0.951            0.95                0.1630           210.0           8.1          0.17        0.17          NO          0.95   0.911     1.254         0.522      0.49     32        1      186     225
MERCURY                              0.85                                0.000621            1.8          0.025         0.00        0.00          NO          0.95   0.913     0.051         0.306      0.30     33        1      186     225
NICKEL                               0.99             0.99                0.6830            74.0           8.20         0.70        0.70          NO          0.95   0.913     4.004         0.183      0.18     33        1      186     225
SILVER                               0.85                                                    1.9           NA           0.00        0.00          NO          0.95   0.911     0.596         0.423      0.41     32        1      186     225
ZINC                                 0.946            0.946                0.8880           90.0           81.0         1.13        1.09          NO          0.95   0.913     49.340        0.414      0.40     33        1      186     225

 This spreadsheet calculates the reasonable potential to exceed state water quality standards for a small number of samples. The procedure and calculations
 are done per the procedure in Technical Support Document for Water Quality-based Toxics Control, U.S. EPA, March, 1991 (EPA/505/2-90-001) on page 56.
 User input columns are shown with red headings. Corrected formulas in col G and H on 5/98 (GB)
                                                                                                                                                                                                                                                                                                                                                                         Page 77 of 101


                                                                                                                                                                                                                                                             Table H-3: South WWTP – Reasonable Potential to Exceed the Water Quality Standards
Fact Sheet for NPDES Permit WA-002958-1                                                                         Page 78 of 101
King County South Wastewater Treatment Plant



    Table H-4: South WWTP – Chlorine Limit to Meet Water Quality Limit


                                                                 Permit Limit Calculation Summary
                                    Metal    Metal             Water      Water
                     Acute Chronic Criteria Criteria Ambient   Quality    Quality     Average     Maximum
                      Dil'n  Dil'n Translat Translat Concentr Standard   Standard     Monthly     Daily Limit
                     Factor Factor    or       or     ation    Acute     Chronic    Limit (AML)     (MDL)           Comments
   PARAMETER                        Acute Chronic      ug/L     ug/L       ug/L        ug/L          ug/L

        Chlorine     186.00   225.00                           13.00      7.50        923.7        2418.0            New DF

                                                                                     500.0         750.0        Technology-Based




   Waste Load Allocation (WLA) and Long                                     Statistical variables for permit limit
     Term Average (LTA) Calculations                                                     calculation
                                         LTA                                                          # of
                                        Coeff.  LTA                      Coeff. AML        MDL Sample
 WLA    WLA           LTA        LTA     Var. Prob'y            Limiting  Var. Prob'y Prob'y         s per
 Acute Chronic       Acute      Chronic (CV)   Basis              LTA    (CV) Basis Basis Month
 ug/L   ug/L         ug/L        ug/L decimal decimal             ug/L decimal decimal decimal         n

 2418      1687.50   776.4        890.0     0.60      0.99       776.4        0.60       0.95        0.99        30.00    1.00
Fact Sheet for NPDES Permit WA-002958-1                             Page 79 of 101
King County South Wastewater Treatment Plant
    Table H-5: South WWTP – Reasonable Potential to Exceed Human Health Criteria
Fact Sheet for NPDES Permit WA-002958-1                            Page 80 of 101
King County South Wastewater Treatment Plant
    Table H-5 (Continued): South WWTP – Reasonable Potential to Exceed Human
    Health Criteria
Fact Sheet for NPDES Permit WA-002958-1                          Page 81 of 101
King County South Wastewater Treatment Plant
    Table H-6: South WWTP – Ambient Monitoring Data Summary

                            King County Water Quality Data
                             Station LSNT01 - Central Basin
                           1999 through 2008 - Conventionals
                Salinity    Temperature Dissolved Oxygen Fecal Coliform Bacteria
                 (PSS)           (°C)           (mg/L)       (# organisms/100 mL)
  Minimum         27.0            7.5             4.5                 0.0
  Maximum         31.1           14.0            13.6                 4.0
   Average        30.1           10.3             7.2                 0.2
      90%         30.8           12.4             8.6                 1.0
      95%         30.8           13.0             9.0                 1.0
Fact Sheet for NPDES Permit WA-002958-1                                                                                   Page 82 of 101
King County South Wastewater Treatment Plant
     Table H-7: South WWTP – Dilution Assessment for Temperature

                                                   Marine T-mix
                   T-Mix is based on WAC 173-201A-200(1)(c)(i)--(ii) and Water Quality Program Guidance.

All Data inputs must meet WQ guidelines.
The Water Quality temperature guidance document may be found at:                            http:/ / www.ecy.wa.gov/ biblio/ 0610100.html
Notes:

                                        INPUT                                                 May-Sep               Oct-Apr
1. Chronic Dilution Factor at Mixing Zone Boundary                                                 225                  225

2. Annual max 1DADMax Ambient Temperature (Background 90th percentile)                          14.0 °C              12.5 °C                Max.

3. 1DADMax Effluent Temperature (95th percentile)                                               22.2 °C              18.9 °C                Max.

4. Aquatic Life Temperature WQ Criterion                                                        16.0 °C              16.0 °C

                                      OUTPUT
5. Temperature at Chronic Mixing Zone Boundary:                                                14.04 °C             12.53 °C

6. Incremental Temperature Increase or decrease:                                                0.04 °C              0.03 °C

7. Incremental Temperature Increase 12/(T-2) if T< crit:                                        1.00 °C              1.14 °C

8. Maximum Allowable Temperature at Mixing Zone Boundary:                                      15.00 °C             13.64 °C

A. If ambient temp is warmer than WQ criterion
9. Does temp fall within this warmer temp range?                                                   NO                   NO
10. Temp increase allowed at mixing zone boundary, if required:                                     ---                  ---

B. If ambient temp is cooler than WQ criterion but within 12/(Tam b-2) and within 0.3 °C
   of the criterion
11. Does temp fall within this incremental temp. range?                            NO                                   NO

12. Temp increase allowed at mixing zone boundary, if required:                                     ---                  ---
C. If ambient temp is cooler than (WQ criterion-0.3) but within 12/(Tam b-2) of the criterion

13. Does temp fall within this Incremental temp. range?                                            NO                   NO

14. Temp increase allowed at mixing zone boundary, if required:                                     ---                  ---

D. If ambient temp is cooler than (WQ criterion - 12/(Tam b-2))
15. Does temp fall within this Incremental temp. range?                                           YES                  YES

16. Temp increase allowed at mixing zone boundary, if required:                                NO LIMIT             NO LIMIT
17. Do any of the above cells show a temp increase?                                                NO                   NO

18. Temperature Limit if Required?                                                            NO LIMIT             NO LIMIT
Fact Sheet for NPDES Permit WA-002958-1                                                                 Page 83 of 101
King County South Wastewater Treatment Plant
    Table H-8: South WWTP – Dilution Assessment for Fecal Coliform Bacteria

South Plant WWTP Receiving Water Calculations
     Chronic Dilution Factor                                            225   1
     Acute Dilution Factor                                              186
     Facility Design Max Month Flow                                    144.00 mgd
                                                                       222.82 cfs

Fecal Coliform Dilution Calculation
     Receiving Water Fecal Coliform                                      4      #/100 ml   Ambient Monitoring LSNT01
     Effluent Fecal Coliform - worst case                              2075     #/100 ml Max. Daily Discharge (2004-2008)
     Downstream Fecal Coliform                                          13      #/100 ml
     Difference between mixed and ambient                                9      #/100 ml
     Primary Contact and Shellfish Hab itat Surface Water Criteria      14      #/100 ml Current state WAC designation

     Conclusion: At design flow, the discharge has no reasonable potential for violation of water quality standards for fecal
     coliform.
Fact Sheet for NPDES Permit WA-002958-1                                                     Page 84 of 101
King County South Wastewater Treatment Plant
    Table H-9: South WWTP – Assessment for Impacts to Dissolved Oxygen

South WWTP
      Dissolved oxygen concentration following initial dilution.
      References: EPA/600/6-85/002b and EPA/430/9-82-011

                               INPUT                                                   Source
1. Dilution Factor at Mixing Zone Boundary:                        225 Chronic dilution factor
2. Ambient Dissolved Oxygen Concentration (mg/L):                   4.5 Min. at LSNT01


3. Effluent Dissolved Oxygen Concentration (mg/L):                  4.5 NPDES permit application - Min. value


4. Effluent Immediate Dissolved Oxygen Demand (mg/L):               45 DMR Data Max BOD 5-day
                                                     OUTPUT
Dissolved Oxygen at Mixing Zone Boundary (mg/L):                   4.30

Decrease of 0.2 mg/L = No Measurable Change                        0.20
Fact Sheet for NPDES Permit WA-002958-1                                          Page 85 of 101
King County South Wastewater Treatment Plant
    Table H-10: South WWTP – Assessment for pH

                    Calculation of pH of a mixture in seawater.
             Based on the CO2SYS program (Lewis and Wallace, 1998)
                   http://cdiac.esd.ornl.gov/oceans/co2rprt.html

                                    INPUT

1. MIXING ZONE BOUNDARY CHARACTERISTICS
   Dilution factor at mixing zone boundary                           225.000
   Depth at plume trapping level (m)                                   2.000

2. BACKGROUND RECEIVING WATER CHARACTERISTICS
   Temperature (deg C):                                                14.00 Max
   pH:                                                                  7.80 Avg. 2007 EB Monit. Sta.
   Salinity (psu):                                                     31.10 Max
   Total alkalinity (meq/L)                                             2.40

3. EFFLUENT CHARACTERISTICS
   Temperature (deg C):                                                22.20 Max
   pH:                                                                  8.80 Max
   Salinity (psu)                                                       0.00
   Total alkalinity (meq/L):                                            3.00

4. CLICK THE 'calculate" BUTTON TO UPDATE OUTPUT RESULTS >>>

                                   OUTPUT

CONDITIONS AT THE MIXING ZONE BOUNDARY
  Temperature (deg C):                                                 14.04
  Salinity (psu)                                                       30.96
  Density (kg/m^3)                                                   1023.07
  Alkalinity (mmol/kg-SW):                                              2.35
  Total Inorganic Carbon (mmol/kg-SW):                                  2.25
  pH at Mixing Zone Boundary:                                           7.81
   Fact Sheet for NPDES Permit WA-002958-1                                                                                                    Page 86 of 101
   King County South Wastewater Treatment Plant

APPENDIX I—INDUSTRIAL DISCHARGERS TO COUNTY’S SOUTH WWTP
   F.1. Pretreatment program. Does the treatment works have, or is subject to, an approved pretreatment program? - Yes
   F.2. Number of Significant Industrial Users (SIUs) and Categorical Industrial Users (CIUs). Provide number of each of the
         following types of industrial users that discharge to the treatment works.
         a. Number of non-categorical SIUs. 36
         b. Number of CSIUs.                      29
   F.3.                                                                             Mailing Address                                                         F.7.
   A. O. Smith Water Products Company                                               820 SW 41ST STREET                    RENTON                      98057 METAL FINISHING - CFR 433
   Aero Controls, Inc.                                                              1602 PIKE STREET NW                   AUBURN                      98001 METAL FINISHING - CFR 433
   Aero Controls, Inc.                                                              1610 20TH STREET NW                   AUBURN         98002-3459         METAL FINISHING - CFR 433
   Aerojet-General Corporation                                                      11441 WILLOWS ROAD NE                REDMOND                      98052 METAL FINISHING - CFR 433
   Aramark Uniform & Career Apparel, LLC                                            7810 SOUTH 228TH STREET              KENT                         98032 LAUNDRY-INDUSTRIAL
   B.S.B. Diversified Company Inc.                                                  S. 200 ST. AND 81ST ST.               KENT                        98032 GROUNDWATER REMEDIATION - ORGANICS
   Baker Commodities Inc.                                                           5795 S. 130TH PLACE                   SEATTLE                     98178 RENDERING
   Bakery Chef Company -Ralcorp Frozen                                              6320 S. 190TH STREET                  KENT                        98032 FOOD PROCESSING
   Black Oxide, LLC                                                                 131 30TH STREET NE, SUITE 25          AUBURN                      98002 METAL FINISHING - CFR 433
   Boeing Commercial Airplane - Auburn                                              700 15TH ST. SW                      AUBURN                       98002 METAL FINISHING - CFR 433
   Boeing Commercial Airplane - Renton                                              801 LOGAN AVE. N.                    RENTON                       98055 METAL FINISHING - CFR 433
   Boeing Electronics Center                                                        616 SW 41ST STREET, BLDG.7-107       RENTON                       98055 METAL FINISHING - CFR 433
   Burlington Environmental, LLC                                                    20245 77TH AVE. S.                   KENT                         98032 CENTRALIZED WASTE TREATMENT 437B PSES
   Cedar Grove Composting, Inc.                                                     17825 CEDAR GROVE RD. SE             MAPLE VALLEY                 98038 COMPOSTING-YARD WASTE
   Circuit Services WorldWide                                                       13000 BEL-RED ROAD, NO. 105           BELLEVUE                    98005 ELECTROPLATING - CFR 413
   Coca-Cola Bottling Company of Washington                                         1150 124TH AVE NE                    BELLEVUE                     98005 FOOD PROCESSING-SOFT DRINKS
   Davis Wire Corporation                                                           19411-80TH AVENUE SOUTH              KENT            98032-1190         IRON AND STEEL MANF - CFR 420
   Electrofinishing, Inc.                                                           22630 88TH AVENUE S., UNIT A         KENT                         98031 METAL FINISHING - CFR 433
   Exotic Metals Forming Company                                                    5411 S. 226TH STREET                 KENT                         98032 METAL FINISHING - CFR 433
   Express Finishing                                                                15046 NE 95TH STREET                 REDMOND                      98052 METAL FINISHING - CFR 433
   G & K Services                                                                   1001 SW 34TH ST.                      RENTON                      98055 LAUNDRY-INDUSTRIAL
   Genie Industries - Bld. 2 - Moosewerks                                           7140 180TH AVENUE NE                 REDMOND                      98052 METAL FINISHING - CFR 433
   Genie Industries - Bld. 3 & 4                                                    18340 NE 76TH STREET                  REDMOND                     98052 METAL FINISHING - CFR 433
   Genie Industries - Bld. 6 & 7 - Scissors Plant                                   18700 & 18750 NE 65TH STREET          REDMOND                     98052 METAL FINISHING - CFR 433
   GKN Aerospace Chem-tronics Inc.                                                  20231 72ND AVENUE SOUTH              KENT                         98032 METAL FINISHING - CFR 433
   Green Garden Food Products, Inc.                                                 5851 S. 194TH ST.                    KENT                         98032 FOOD PROCESSING
   Hexcel Corporation                                                               19819 84TH AVE. S.                   KENT                         98032 GROUNDWATER REMEDIATION - ORGANICS
   Honeywell International Inc.                                                     15001 NE 36TH STREET                 REDMOND                      98073 METAL FINISHING - CFR 433
   Hytek Finishes Company                                                           8127 S. 216TH STREET                  KENT                        98032 METAL FINISHING - CFR 433
   International Paper Company (fka Weyerhaeuser)                                   1899 120TH AVENUE NE                 BELLEVUE                     98005 CORRUGATED CONTAINER
   January Company                                                                  9844 40TH AVE. S.                     SEATTLE                     98118 FOOD PROCESSING-MEATS
   Kenworth Truck Company - Renton                                                  1601 N. 8TH STREET                    RENTON                      98057 METAL FINISHING - CFR 433
   King County CIP - Juanita Bay Pump Station                                       9304 JUANITA DRIVE NE                 KIRKLAND                    98034 CONSTRUCTION DEWATERING
   King County DOT - Renton Decant Facility                                         155 MONROE AVE. NE                   RENTON          98056-4199         DECANT STATION
   King County SWD - Cedar Hills Landfill                                           16645 228TH AVENUE SE                 MAPLE VALLEY                98038 SOLID WASTE - LANDFILL
   King County SWD - Factoria Transfer Station                                      13800 SE 32ND ST.                     BELLEVUE                    98005 SOLID WASTE - TRANSFER FAC
   King County SWD - Houghton Transfer Station                                      11724 NE 60TH STREET                 KIRKLAND                     98033 SOLID WASTE - TRANSFER FAC
   King's Command Foods, Inc.                                                       7622 S. 188TH ST.                    KENT                         98032 FOOD PROCESSING-MEATS
   Metro Transit South Base                                                         12100 E MARGINAL WAY SOUTH            TUKWILA                     98168 TRANSPORTATION FACILITY
   Mikron Industries                                                                1034 SIXTH AVENUE NORTH               KENT                        98032 PLASTIC PRODUCTS MANF. 463
   Oberto Sausage Company - Kent                                                    7060 SOUTH 238TH STREET              KENT                         98032 FOOD PROCESSING-MEATS
   Pacific Metallurgical Inc.                                                       925 5TH AVENUE SOUTH                 KENT                         98035 METAL FINISHING - CFR 433
   Pacific Propeller International, LLC                                             5802 SOUTH 228TH STREET              KENT            98032-1810         ELECTROPLATING - CFR 413
   Port of Seattle, Seattle-Tacoma International Airport, BW                        17025 AIR CARGO ROAD                 SEATAC                       98188 CHEMICAL TOILET
   Port of Seattle, Seattle-Tacoma International Airport, IWS                       17801 INTERNATIONAL BOULEVARD SEA TAC                             98188 GENERAL TYPE
   Protective Coatings Inc.                                                         1215 N. SECOND AVENUE                 KENT                        98032 ELECTROPLATING - CFR 413
   Prototron Circuits Inc.                                                          15225 NE 95TH STREET                 REDMOND                      98052 METAL FINISHING - CFR 433
   Puget Sound Recycling                                                            523 A STREET SE                      AUBURN                       98002 CENTRALIZED WASTE TREATMENT 437 PSNS
   Quala Systems, Inc.                                                              19929 77TH AVENUE SOUTH               KENT                        98032 TRANSPORTATION FACILITY
   Quality Finishing Inc.                                                           12704 NE 124TH STREET, #42            KIRKLAND                    98034 ELECTROPLATING - CFR 413
   Rexam Beverage Can Company                                                       1220 NORTH SECOND AVENUE              KENT                        98032 COIL COATING - CFR 465
   Safeway, Inc. - Bellevue Beverage Plant                                          1500 124TH AVE NE                    BELLEVUE                     98005 FOOD PROCESSING-SOFT DRINKS
   Safeway, Inc. - Milk Plant                                                       1723 124TH AVENUE NE                 BELLEVUE                     98005 FOOD PROCESSING-DAIRY
   Seattle, City of-SWD - Kent Highlands                                            23240 MILITARY ROAD S.               KENT                         98032 SOLID WASTE - LANDFILL
   Shasta Beverages                                                                 1227 ANDOVER PARK EAST               TUKWILA                      98188 FOOD PROCESSING-SOFT DRINKS
   Skills, Inc. - Auburn Facility                                                   715 - 30TH STREET NE                  AUBURN                      98002 METAL FINISHING - CFR 433
   Smith Fabrication Inc.                                                           1609 S. CENTRAL AVE. NO. 11           KENT                        98032 METAL FINISHING - CFR 433
   Stoller Metals, Inc.                                                             22809 86TH AVENUE S                  KENT                         98031 METAL FINISHING - CFR 433
   Tri-Way Industries, Inc. (Auburn)                                                506 44TH STREET NW                   AUBURN                       98001 METAL FINISHING - CFR 433
   Truesoups Division of H.J. Heinz Company, L. P.                                  26401 79TH AVENUE SOUTH              KENT                         98032 FOOD PROCESSING-SOUPS
   TTM Technologies, Inc.                                                           17550 NE 67TH COURT                  REDMOND                      98052 METAL FINISHING - CFR 433
   Vectra Fitness Inc. Kent Facility                                                19021 80TH AVENUE SOUTH               KENT                        98032 METAL FINISHING - CFR 433
   Western Metal Art and Sign                                                       7042 SOUTH 188TH STREET               KENT                        98032 METAL FINISHING - CFR 433
   Western Pneumatic Tube                                                           835 6TH SOUTH                        KIRKLAND                     98033 METAL FINISHING - CFR 433
   WestFarm Foods/Darigold - Issaquah                                               611 FRONT STREET NORTH               ISSAQUAH                     98027 FOOD PROCESSING-DAIRY
   Fact Sheet for NPDES Permit WA-002958-1                                              Page 87 of 101
   King County South Wastewater Treatment Plant

APPENDIX J—RESPONSE TO COMMENTS

   Comments Received During Public Hearing – September 3, 2009

   Betsy Cooper, King County Wastewater Treatment Division

   My name is Betsy Cooper. I am the NPDES Permit Administrator for the Wastewater Treatment
   Division. King County’s address is 201 S Jackson Street in Seattle. I am pleased to give
   comments tonight in reference to the draft South Plant permit.

   I want to thank the Department of Ecology for running this public hearing.

   More than 40 years ago, the Metropolitan Sewer Authority and now King County began the
   process of helping to protect public health and the citizens and the environment by beginning
   wastewater treatment in this region.

   Before South Plant, basically there were, you know, wastewater from homes or industries was
   flowing directly into Lake Washington or into Puget Sound and the beaches were affected by
   those discharges and the people who used them and fishing and swimming was not necessarily
   the thing you wanted to do all the time in this area. However, the region decided to address that
   issue and in 1958, the region pulled together to create a regional government called METRO and
   that is now incorporated into King County’s Wastewater Treatment Division.

   In reference to the South Plant, South Plant began, as Mark noted earlier in his presentation, as a
   secondary treatment plant in 1965 and fairly soon after additional upgrades began to increase the
   capacity of that secondary treatment. Initially there was a discharge into the Green River of this
   effluent but in the late 80s a new 12 mile tunnel was built to Duwamish Head and then outfalls
   were built there approximately 10,000 feet long and they discharged our treated effluent into
   about 625 feet of water.

   The South Plant today treats approximately 94 million gallons of wastewater every day for the
   residents and businesses of the area and that treatment removes tons of pollutants and creates
   resources for our region. I’ll talk a little about both the treatment at the plant and those resources
   that we are involved in creating

   And we also at the plant, we treat septage, as well the materials that are removed from septic
   tanks and in 1998 about 20 million gallons of septage was also treated at the plant.

   So, South Plant as Mark mentioned, really does create a high quality effluent and in compliance
   with all the existing requirements of the permit and we consistently exceed those requirements.

   We also, as part of the wastewater treatment program, have an industrial wastewater program
   that is involved in trying to remove pollutants before they reach the influent to the plant. One
   example of that, a very successful example, is the dental waste program, were the County
   determined that it was important to remove mercury from the sources, the main sources of
   mercury to our system, which are dental offices. So that program, since 2003, has removed
Fact Sheet for NPDES Permit WA-002958-1                                             Page 88 of 101
King County South Wastewater Treatment Plant
approximately 375 pounds of mercury, from what would have been in our influent and perhaps
moving through our system and into our environment.

One of the other major things that King County does to protect against pollution is vigorous
environmental education programs that we try to invite people to the plant so that they
understand where that water goes, as well we try to inform people about what kinds of choices
they can make to improve the environment.

One other component of King County’s efforts to try and protect Puget Sound, in addition to the
way we operate the plant, really is to participate in a variety of different activities that Ecology
and other organizations such as the Puget Sound Partnership are doing to try to protect Puget
Sound. We feel that being a partner in regional efforts is important and we put substantial
resources and effort to do that.

But, the other large component that we mentioned, was we create resources from wastewater. It
is a recycling plant as well. As we talked about the effluent leaving the outfall, we also generate
about 6500 wet tons of biosolids every year and those are used as fertilizer for enriching soils
and they alone represent a significant removal of nutrients and a reuse of those nutrients for
beneficial use.

Also the gas system that has been created at South Plant uses digester gas to run specific
equipment in the plant as well as to send scrub gas back to Puget Sound Energy for its use. An
example that has been given of the amount of gas we send back can typically light 2500 homes.

The one other very important recycling program we have is the reclaimed water program where
approximately 80-94 million gallons of reclaimed water is used in the plant every year or on-site
and then 2-6 million gallons is sent off-site for irrigation uses and other uses. And the
Wastewater Treatment Division is looking is looking to create a sort of larger vision for that
reclaimed water program and our other plants will be participating in that and we are looking to
expand that reclaimed water program so that there will be less flow to Puget Sound from our
system.

So in conclusion, we are very proud of our role that South Plant plays in the protection of Puget
Sound and we are happy to give comments tonight. Thank you.


                               End of Public Hearing Comments


Ecology’s response to King County’s Oral Testimony:

Comments noted.
Fact Sheet for NPDES Permit WA-002958-1                                          Page 89 of 101
King County South Wastewater Treatment Plant


Comments from People For Puget Sound (via e-mail)

September 18, 2009


Karen Burgess
Mark Henley
Department of Ecology
Northwest Regional Office
3190 - 160th Avenue SE
Bellevue, WA 98008-5452
Via E-mail: kbur461@ecy.wa.gov, mahe461@ecy.wa.gov, tmil461@ecy.wa.gov

RE: King County South Wastewater Treatment Plant draft NPDES Permit (No. WA-002958-1)

To Karen and Mark,

We are writing to comment on the King County South Wastewater Treatment Plant draft NPDES
Permit (No. WA-002958-1), dated July 28, 2009.

People For Puget Sound is a nonprofit, citizens’ organization whose mission is to protect and
restore Puget Sound and the Northwest Straits.

We are attaching our recent (February 13, 2009) West Point Permit comment letter because most
of the background information and the comments apply to the South Plant as well.

The King County South Plant is a major facility with potential adverse impacts to the health of
Puget Sound. Together with the King County West Point facility, these two plants discharge
about 50 percent of the treated sewage wastewater to the surface waters of the Puget Sound
basin.

We are pleased that Ecology has incorporated into this draft permit many of the same
requirements that have been included in the new West Point facility permit based on our and
other stakeholder concerns. These requirements include improved industrial user monitoring, a
trigger for a nutrient reduction feasibility analysis if the current Ecology-led Puget Sound
dissolved oxygen studies show that South Plant is contributing to the nutrient loading problem,
and improved water and sediment monitoring.

In addition, we would like to express appreciation for the improved Fact Sheet. This Fact Sheet
is well written, more detailed and overall is substantially improved over other Fact Sheets we
have reviewed and also includes improved maps, photos, graphs, etc. The mixing zone diagrams
are excellent. The changes in the permit and the justifications are well explained. The
wastewater effluent characterization is the model that we hope all Ecology Fact Sheets will
follow.
Fact Sheet for NPDES Permit WA-002958-1                                         Page 90 of 101
King County South Wastewater Treatment Plant
Our comments follow:

   1. Omission of relevant ongoing studies and reports. We recommend that the Fact Sheet
      should include mention of important studies being undertaken by Ecology that relate to
      the permit such as the toxic loadings studies.

   Ecology’s response: Generally, the fact sheet is used to provide information specific to the
   permit, and we do not typically include regional or statewide studies in individual fact sheets.
   The best source for information regarding broad studies is the Ecology webpage. These studies
   are ongoing and only the webpage provides the most up-to-date information. The web links to
   these studies was provided in the Public Notice as follows:
   Puget Sound Water Quality:
   http://www.ecy.wa.gov/puget_sound/index.html
   South Sound Dissolved Oxygen Study:
   http://www.ecy.wa.gov/puget_sound/dissolved_oxygen_study.html
   Control of Toxic Chemicals in Puget Sound
   http://www.ecy.wa.gov/programs/wq/pstoxics/index.html

   Special Condition S17 has been added to the permit to address possible outcomes of the South
   Sound Dissolved Oxygen Study and the Puget Sound Hydrodynamic Modeling.


   2. Endocrine disrupters. People For Puget Sound requests that Ecology include monitoring
      of emerging chemicals including pharmaceuticals (at a minimum, the chemicals currently
      being assessed in Ecology’s study), PBDEs and additional chemicals that were detected
      in King County’s surface water study in the new permit. A baseline is needed so that the
      success of future work on source reduction/pollution prevention can be assessed.

   Ecology’s response: At this time, Ecology is not putting requirements for EDC testing in
   individual permits. Ecology is awaiting the results of our current study on pharmaceuticals and
   personal care products (PPCPs) before making programmatic decisions concerning PPCPs.


   3. S6.E. Source Tracking Characterization. We are pleased that Ecology has included our
      request to require King County to begin the process of looking at sources of toxic chemicals
      in a more systematic way. At this point, King County does not have an inline characterization
      of the toxic chemical loads in each section of their system (i.e., areas in the system where
      lead, mercury, phthalates, etc. have higher concentrations) and so does not know where the
      problems are in terms of being able to reduce sources of toxic chemicals to the facility.

      Our concerns are:

          a. One report is inadequate. We request that Ecology request that a source tracing plan
             be submitted by 6 months from the permit start date and that a yearly progress update
             be due by June 1 of each year of the permit cycle. Furthermore, the plan and progress
             reports should be sent to interested stakeholders, including People For Puget Sound
             by King County.
Fact Sheet for NPDES Permit WA-002958-1                                              Page 91 of 101
King County South Wastewater Treatment Plant
             b. Our key goal in requesting this study in the first place was that the sewer line itself
                be tested, branch by branch. This proposed S6.E.study does not include that key
                requirement and we request that it do so.

   Ecology’s response: At this time, Ecology believes that Special Condition S6.E is an appropriate
   requirement for source characterization. King County relies on their Industrial Waste Program
   (KCIW) to regulate permitted and authorized discharges from significant industrial users. Ecology
   has delegated pretreatment authority to King County and inspects their program annually.


   4. Pretreatment. The permit or the Fact Sheet should list in an appendix the name and type of
      industry for each pretreatment facility.

   Ecology’s response: The draft permit included Appendix I which listed the name and type of
   industries that discharge into the County’s South conveyance system. Appendix I is retained for
   the final fact sheet.


   5. Mailing list. Stakeholder and interested persons list for permit should be added as an appendix.

   Ecology’s response: In regard to the draft South Plant NPDES permit, comments were received
   by only three stakeholders: People For Puget Sound, City of Everett and King County. Ecology
   does not believe that a separate appendix is necessary as there was limited public participation in
   this draft permit.


   6. Public Participation. As a final note, we are concerned that the public hearing for this
      permit was held on the Thursday before the Labor Day holiday weekend. For future public
      hearings associated with major permits, we request that key stakeholders be contacted to
      help determine the optimal date for holding hearings.

   Ecology’s response: It is often difficult to select a date for the public hearing that works for
   everyone and that fits the timeline for the issuance of the permit. In an e-mail dated August 3,
   2009, we invited someone from your organization to attend the informal public meeting and to
   provide testimony on your behalf. No other stakeholders expressed reservations regarding the
   hearing date.

Thank you for the opportunity to comment. Please contact me with questions at (206) 382-7007
X215.

Sincerely,



Heather Trim
Urban Bays and Toxics Program Manager
Attachment
Fact Sheet for NPDES Permit WA-002958-1                                         Page 92 of 101
King County South Wastewater Treatment Plant


Comments from King County (via e-mail and USPS letter)

September 18, 2009

Tricia Miller
Water Quality Permit Coordinator
Northwest Regional Office
Dept. of Ecology
3190 160th Avenue SE
Bellevue, WA 98008-5452

RE: Comments on the Draft South Plant NPDES Permit (No. WA-002958-1) Renewal

Dear Ms. Miller:

Thank you for the opportunity to comment on the South Plant Permit Renewal. King County’s
comments are below.

Permit Comments

   •   Page 14 - S2.C – Sampling and Analytical Procedures - For consistency, after the reference to
       40 CFR 136 in the second paragraph of S2.C, please add: "Methods identified in Appendix A
       may be used." This is the same language that was added to section S6B.

   Ecology’s response: Additional requested language is not necessary. Special Conditions
   S2.A and S2.B explicitly allow for laboratory methods in Appendix A to be used.


   •   Page 32 – S11.1 or 2 – Receiving Water Characterization - The analysis of Total and
       Dissolved Metals in a saltwater matrix will required methods and detection limits that are
       not in Appendix A. Therefore, please add, to either #1 or #2 of these sections: "Conduct
       all chemical analysis using the methods and detection levels identified in the approved
       SAP/QAPP". This will allow the methodologies to be specified and approved by Ecology
       through the SAP/QAPP, giving Ecology in either case, the final approval.

   Ecology’s response: Additional requested language is not necessary. S11.9 explicitly allows
   for chemical analyses using methods and detection levels identified in Appendix A, or as
   identified in the Sampling and Quality Assurance Plan.


   •   Page 33 – S12C – Source of Sediment Toxicity Study - This section calls for King County
       to undertake an analysis of the source of sediment toxicity for which Ecology has no
       guidance. The absence of guidance on this issue is understandable as the relationship
       between sediment-bound and deposited chemicals and toxicity is not as well studied as
Fact Sheet for NPDES Permit WA-002958-1                                             Page 93 of 101
King County South Wastewater Treatment Plant
       water column relationships. The process and procedures used in traditional Toxicity
       Reduction Evaluation studies are not directly transferable or possibly even appropriate for
       sediments. Further, since there has not been any indication that there is a toxicity concern at
       this site, it is presumptive and premature to have such a requirement in the permit at this
       time; particularly so if there is no defined process to assess such a concern. Including this
       requirement in this permit, prior to any indication of toxicity concerns near South Plant’s
       outfall is unwarranted and we request this requirement be removed.

       A more appropriate approach to addressing this concern would be to work with the County if
       any toxicity was observed to determine what next steps would be appropriate. Next steps
       would likely vary dependant on the specific findings. They could range from verification
       and further characterization of the problem, to an attempt to identify the source of toxicity or
       even to determine if a sediment impact zone would be appropriate. In addition, guidance
       development and rule making to define such a toxicity evaluation program for sediments is
       needed so that such guidance would be available for those sites where sources of toxicity
       needed to be pursued.

   Ecology’s response: This permit requirement only applies if toxicity is found in the sediment. It
   is in the permit so that if toxicity is found, actions to investigate may be taken immediately
   without a permit revision. Ecology will work with the County to determine what next steps are
   appropriate, if toxicity is found in the sediments. We agree that the next steps may vary
   depending on the nature and severity of the problem. Ecology does not plan to develop specific
   guidance or rule revision to address this topic because this type of activity is varied, occurs very
   infrequently, and should be based on the most current science. USEPA has published a guidance
   document on Sediment Toxicity Identification Evaluation (EPA/600/R-07/080 September 2007)
   that can be used for this purpose.


   •   Page 33 – S12.C – Source of Sediment Toxicity Study - If this section remains in the permit
       the 30-day period for commencement of toxicity source evaluation is much too short,
       especially if additional sampling needed to occur. We request, at a minimum, a 90-day
       period to allow adequate time for discussion of findings to determine that such a step is the
       appropriate action and a clarification that commencement means starting development of a
       sampling plan or starting further studies with existing materials, as appropriate. We further
       request that the clock would not run during the period of time required for development of
       what an appropriate sediment toxicity evaluation would comprise. Based on the timeframe
       for Ecology’s development of whole effluent toxicity identification procedures in the 1990’s,
       this could be a considerable period of up to one to two years. As the period of time is not
       discernable, the only implementable approach in the permit is to suspend the clock during
       this process.

   Ecology’s response: Conditions may change during the time that samples are stored, including
   loss of volatile constituents and changes in redox state. Toxicity evaluations should begin as
   soon as possible after toxicity is detected, or there is increased potential for inconclusive results.
   There are already existing Sediment Toxicity Identification Evaluation procedures published by
   the USEPA. Thirty days to begin toxicity identification is reasonable.
Fact Sheet for NPDES Permit WA-002958-1                                             Page 94 of 101
King County South Wastewater Treatment Plant

   •   Page 33 – S12.C- Also, if this section remains in the permit, please change the final sentence
       of Section S12.C to read: "The Permittee must submit to Ecology the results of the sediment
       toxicity investigation within three months of completion of testing."

   Ecology’s response: The permit has been modified with the additional language.


Fact Sheet Comments

   •   Page 23 – Sediment Characterization - In the second paragraph, please correct the first
       sentence to read: "In November 2001, King County performed sediment sampling from 0 to 2
       cm depth at 13 (rather than 10) sample locations near the two marine outfalls."

   Ecology’s response: The fact sheet has been corrected.


   •   Page 23 – In the second paragraph, it is not clear why a Bis(2-ethylhexyl)phthalate
       concentration of 43 ppm at Station RT625SD is presented in text here and in the Table 8 on
       page 24, since the reported concentration did not exceed the SMS chemical criterion and, the
       datum is further qualified with a "B" flag. Such data should be considered at best, an
       estimate. In addition, all other samples during that sampling period had Bis(2-
       ethylhexyl)phthalate concentrations below 10 ppm. Therefore, it is requested that the fourth
       and fifth sentences be deleted from this paragraph.

   Ecology’s response: The table title is “Detected Chemicals Above or Approaching SQS
   Criteria.” This sample is close to the SQS criteria. Since it is qualified with a “B” flag, it is less
   precise than other measurements, and may actually be at a level that can cause effects. There is
   nothing incorrect in the representation of the facts in the fact sheet.


   •   Page 23 – In the third paragraph, please correct the first sentence to read: "In October
       1999, King County performed sediment sampling from 0 to 2 cm depth at 13 (rather than
       12) sample locations near the two outfalls."

   Ecology’s response: The fact sheet has been corrected.


   •   Page 23 – In the fourth paragraph, please correct the second sentence to read: "In October
       1997, the County measured concentrations of hexachlorobenzene at three locations
       (RT700NS, RT625ND, RT625SD) that exceeded the Sediment Quality Standards numeric
       criterion”. (There were no exceedances of benzoic acid in 1997. There was one exceedance
       of the SQS/CSL criterion for Benzoic Acid at one location (LSDSO2) in 1995 but 1997, 99,
       and 2001 data have shown no such exceedances.) Then, add the following sentence after
       the second sentence: "During both the 1999 and 2001 sediment monitoring events,
       hexachlorobenzene was not detected at these three locations, nor any of the other 10
       locations sampled and, the method detection limits were all below the associated Sediment
       Quality Standard chemical criterion."
Fact Sheet for NPDES Permit WA-002958-1                                         Page 95 of 101
King County South Wastewater Treatment Plant
   Ecology’s response: The fact sheet has been modified with the correct date for the benzoic acid
   exceedance. The requested additional sentence is not necessary and does not fit in this paragraph
   since this paragraph speaks to the timeframe of 1994-1997.


   •   Page 24 – We do not feel that Table 8 should remain in the Fact Sheet. The three locations
       that exhibited some exceedances of Hexachlorobenzene in 1997, exhibited no exceedances in
       two subsequent sampling events. As mentioned above, the Benzoic acid datum mentioned
       was from 1995, not 1997, and data from 1997, 1999, and 2001 do not exhibit and exceedances
       for Benzoic acid. Finally, the Bis(2-ethylhexyl)phthalate data listed in the table are not
       exceedances of the standard. Therefore, we request the table be deleted from the Fact Sheet.

   Ecology’s response: Table 8 provides a historical summary of exceedances or chemicals
   approaching the criteria. Once the date is changed from 1997 to 1995 for benzoic acid, this is an
   accurate representation of the facts. The table will be retained in the fact sheet.


   •   Page 44 – Sediment Quality – Please delete the second bullet under the second paragraph of
       this section as it is an incorrect statement. As mentioned above, Benzoic acid was not
       detected in any of the 8 sediment samples collected during the 1997 sediment-monitoring
       event. Dry-weight normalized detection limits for the 8 samples ranged from 338 to 368
       µg/Kg, which is well below the SQS/CSL criterion of 650 µg/Kg. Benzoic acid was not
       detected in any of the 13 samples collected during the 1999 monitoring event, at a similar
       range of dry-weight normalized detection limits. During the 2001 sediment monitoring event,
       analytical detection limits had improved significantly for benzoic acid and this compound was
       detected in all 13 samples at concentrations ranging from 342 to 553 µg/Kg, all below the
       SQS/CSL criterion.

   Ecology’s response: The draft fact sheet was intended to note hexachlorobenzene as an
   exceedance, and not benzoic acid, under the second bullet. The fact sheet has been corrected to
   mention hexachlorobenzene instead of benzoic acid.


   •   King County certainly accepts the idea that Ecology would require additional sampling at the
       outfalls to check sediment conditions as these sites not been sampled for almost 10 years.
       However, as noted in earlier comments on this matter, it is incorrect and misleading to
       represent the current sediment dataset as indicating that there has been sediment
       contamination at these sites and we request that this section not present that impression
       because it is not supported by the data.

   Ecology’s response: This section is intended to provide a factual summary of existing data.
   There have been past exceedances of the chemical criteria. We also state in a summary on page
   23 that past sediment monitoring does not generally indicate sediment toxicity or violation of
   SMS criteria.
Fact Sheet for NPDES Permit WA-002958-1                                          Page 96 of 101
King County South Wastewater Treatment Plant

   •   Page 44 – With regard to the fourth bullet under the second paragraph which describes the
       requirement for the sample to be of the top 10 centimeters rather than the top
       2 centimeters - this is a significant paradigm shift. The most-recent version of the Sediment
       Sampling and Analysis Plan Appendix (Ecology 2008) still recommends the 0- to 2-cm
       depth stratum when sampling sediment around permitted outfalls. It states: “In some cases,
       monitoring data may be used to interpret temporal changes in sediment conditions. Such
       cases may include, for example, ambient monitoring programs, monitoring of conditions in
       the vicinity of a permitted discharge, or monitoring of a cap placed over contaminated
       sediments as part of remediation. In such cases, it would be more appropriate to limit the
       sampling to the uppermost 2 cm of sediment, which would represent the most recently
       deposited particulate matter. If deeper (e.g., 10 cm) sediment samples were collected and
       analyzed, older sediment would be included in the samples, making it more difficult to
       detect temporal changes in sediment conditions.” (SAPA, Ecology 2008).

       If, as was suggested in discussions with Ecology staff, the purpose of 10 cm sampling is really
       a one-time assessment for compliance with water quality standards (the Sediment
       Management Standards), we recommend that this is clarified in the permit and fact sheet. It
       would also be helpful to identify that following a demonstration of compliance; future
       sampling will revert to the 2-cm depth consistent with existing guidance. This will provide a
       clearer demonstration of intent for the next permit.

   Ecology’s response: The top 10 centimeters of sediment is considered the biologically-active
   zone for Puget Sound and is used for compliance with the Sediment Management Standards.
   Sediment samples from the top 2 cm have been used in the past for trend analysis. In the past
   several years, we have been asking for 10 cm depth samples at NPDES outfalls so that we may
   evaluate compliance with the Sediment Management Standards. It is not just a one-time
   assessment of compliance. Ecology has discretion whether to request 10 cm or 2 cm samples
   depending on the purpose of the sampling study.

   The SAPA was updated in 2008 to add a new appendix with procedures for entering data into
   the EIM database. Other sections of the SAPA were not updated at that time.


   •   Page 44 – Please add the following language to the fifth bullet under the second paragraph:
       "Although not required, King County has performed benthic community analysis during two
       previous sediment monitoring events. Analysis of the benthic data indicates a healthy
       benthic community, typical of deep, depositional environments in Puget Sound."

       The benthic community proximal to the South Treatment Plant outfalls was characterized in
       both 1999 and 2001, with triplicate samples collected from 5 stations proximal to the outfalls
       and one reference station, located 2,500 feet from the outfalls, at a similar depth. During
       both monitoring years, the benthic community showed no impact from the outfalls and no
       apparent gradient in benthic community indices exists, with respect to proximity to or
       distance from the outfalls. Tables of the benthic indices may be found at the following links:
       http://your.kingcounty.gov/dnrp/library/2001/kcr64/99sec3.pdf
       http://your.kingcounty.gov/dnrp/library/2002/kcr64/Section3.pdf
Fact Sheet for NPDES Permit WA-002958-1                                            Page 97 of 101
King County South Wastewater Treatment Plant
   Ecology’s response: Although the Sediment Management Standards require submittal of any
   existing sediment data (WAC 173-204-610), these benthic community data have not been
   submitted to Ecology’s EIM database. If King County wanted these data included in the fact
   sheet summary, the data should have been submitted to Ecology and brought to our attention
   with the permit renewal application or during entity review of the draft fact sheet and permit.
   Since we do not have this data, nor do we have adequate time to review it before permit issuance,
   we can not include the requested quote as it is not confirmed at this time. Please provide EIM
   benthic community data, summary report, and bench sheets to Ecology for review, verification,
   and approval.


   •   Page 44 – We recognize that Ecology can require additional sediment testing above its
       regular tiered approach paradigm. However, to indicate that the Ecology will be expecting
       four bioassays analyses be undertaken without specific SMS exceedances is another
       significant paradigm shift and one that again does not seem warranted based on the existing
       data that has clearly demonstrated there is little indication of toxicity in the vicinity of the
       outfalls (as presented below):

       o Sediments in the vicinity of the South Plant outfalls have been tested for sediment
         contamination since the mid- 1990’s. Each sampling event have taken sediments from
         multiple sites – as many as 13 in the most recent sampling events, with an overall total
         of 48 samples. In the last two events, the benthic community was also sampled. In total
         these samples represent a significant data set.

       o The two most recent sampling events (2001 and 1999), had no detected sediment
         chemical concentrations that exceeded any Sediment Management Standards chemical
         criterion. During the 2001 monitoring event, analytical method detection limits had
         improved to the point that all method detection limits (MDLs) met SQS chemical
         criteria with one exception. The dry-weight normalized MDL for 2-Methylphenol
         exceeded the SQS of 63 ug/Kg DW in four of 13 samples, ranging from 64 to 67 ug/Kg
         DW. This is merely an artifact of slightly lower percent solids concentrations in these
         four samples as 2-Methylphenol was not detected in any of the 13 samples, 9 of which
         had MDLs that met the SQS criterion.

       o The only detected exceedances found in earlier sampling events are summarized below
         and do not indicate any pattern of exceedances or the existence of current toxicity
         concerns:

                  Hexachlorobenzene detected in samples collected from three stations proximal
                  to the outfalls during the 1997 monitoring event. Two of these concentrations
                  (0.954 and 1.87 mg/Kg OC exceeded the SQS chemical criterion of 0.38
                  mg/Kg OC. The third concentration of 2.52 mg/Kg OC exceeded the CSL
                  chemical criterion of 2.3 mg/Kg OC. All three of these stations were sampled
                  again in both 1999 and 2001, during which hexachlorobenzene was not
                  detected, with a method detection limit that met the SQS chemical criterion.
Fact Sheet for NPDES Permit WA-002958-1                                           Page 98 of 101
King County South Wastewater Treatment Plant
                  Benzoic acid was detected at a concentration of 1,480 ug/Kg DW in one sample
                  collected during the 1994 monitoring event. This concentration exceeded the
                  SQS/CSL chemical criterion of 650 ug/Kg DW. The station from which this
                  sample was collected was located approximately 3,000 feet from the outfall.
                  Benzoic acid was not detected at the station that was located equidistant between
                  the two outfalls.

       o The benthic community proximal to the South Treatment Plant outfalls, characterized
         in both 1999 and 2001, showed no impact from the outfalls and no apparent gradient
         in benthic community indices exists, with respect to proximity to or distance from the
         outfalls (see comment above).

       o Whole Effluent Toxicity Testing has been performed consistently since 1986 on South
         Plant effluent. No concerns regarding effluent toxicity have been identified. No
         toxicity-based requirements have been determined to be needed in this permit. Limits
         earlier imposed on metals concentrations where removed in the 1990’s because metals
         data demonstrated they were no longer warranted.

       We contend that if such an significant and expensive bioassay requirement is being added to
       this permit that there needs to be a compelling case to suspect that sediment contamination,
       and thus toxicity, is present. We submit that no such case can be made and, in fact, that the
       data support a compelling case that toxicity is not indicated at this site. We therefore request
       that the expectation of bioassays should continue to be triggered only if a sediment quality
       exceedance is observed as has been typical for NPDES permits to date.

   Ecology’s response: The Sediment Management Standards provide Ecology with specific
   authority to evaluate NPDES discharges in consideration of multiple factors including discharge
   characteristics, receiving water characteristics, and cost mitigating factors. Ecology’s request for
   toxicity testing at this location was not based solely on past chemistry data, but also because of the
   size of the discharge and consistency with permits at other wastewater treatment plants of this size.
   The West Point Wastewater Treatment Plant, which has a similar size discharge, has had many
   bioassays performed near the outfall and has found toxicity, even when concentrations are below
   the chemical criteria.

   However, in this case Ecology has considered your request, and will only require bioassays to be
   performed if the chemical concentrations are near or above the numeric chemical criteria in the
   Sediment Management Standards.

Thank you for consideration of our comments. If you have any questions regarding these comments,
please contact me at 206-263-3728.

Sincerely,


Betsy Cooper
NPDES Coordinator
Cc: Mark Henley, Permit Manager, Dept of Ecology NWRO
Fact Sheet for NPDES Permit WA-002958-1               Page 99 of 101
King County South Wastewater Treatment Plant


Comments from the City of Everett (via USPS letter)
Fact Sheet for NPDES Permit WA-002958-1        Page 100 of 101
King County South Wastewater Treatment Plant
Fact Sheet for NPDES Permit WA-002958-1                                            Page 101 of 101
King County South Wastewater Treatment Plant


Ecology’s response to Issue #1: The Sediment Management Standards provide Ecology with
specific authority to evaluate NPDES discharges in consideration of multiple factors including
discharge characteristics, receiving water characteristics, and cost mitigating factors. Ecology’s
request for toxicity testing at the South plant outfalls was not based solely on past chemistry data,
but also because of the size of the discharge and consistency with permits at other wastewater
treatment plants of this size. The West Point Wastewater Treatment Plant, which has a similar size
discharge, has had many bioassays performed near the outfall and has found toxicity, even when
concentrations are below the chemical criteria.

However, in this case Ecology has considered the County’s request, and will only require bioassays
to be performed if the chemical concentrations are near or above the numeric chemical criteria in the
Sediment Management Standards.


Ecology’s response to Issue #2: The top 10 centimeters of sediment is considered the
biologically-active zone for Puget Sound and is used for compliance with the Sediment Management
Standards. Sediment samples from the top 2 cm have been used in the past for trend analysis. In the
past several years, we have been asking for 10 cm depth samples at NPDES outfalls so that we may
evaluate compliance with the Sediment Management Standards. It is not just a one-time assessment
of compliance. Ecology has discretion whether to request 10 cm or 2 cm samples depending on the
purpose of the sampling study.

The SAPA was updated in 2008 to add a new appendix with procedures for entering data into the
EIM database. Other sections of the SAPA were not updated at that time.


Ecology’s response to Issue #3: This permit requirement only applies if toxicity is found in the
sediment. It is in the permit so that if toxicity is found, actions to investigate may be taken
immediately without a permit revision. Ecology will work with the County to determine what next
steps are appropriate, if toxicity is found in the sediments. Ecology acknowledges that the next steps
may vary depending on the nature and severity of the problem. Ecology does not plan to develop
specific guidance or rule revision to address this topic because this type of activity is varied, occurs
very infrequently, and should be based on the most current science. USEPA has published a
guidance document on Sediment Toxicity Identification Evaluation (EPA/600/R-07/080 September
2007) that can be used for this purpose.

								
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