Delta Water Quality Regulatory Implications for Drinking Water

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					      Delta Water Quality:
Implications for Utility Compliance
 with the Safe Drinking Water Act


           Edward G. Means III
            Sr. Vice President
  McGuire Environmental Consultants, Inc.

     (For Contra Costa Water District)

                                            Slide 1
          Delta Source Water Quality
 Primary Findings . . .
1. Disinfection Byproducts (DBPs) are a greater public
   health issue than in 1991. Additional DBPs likely to be
   regulated in future and DBP regulations will become more
   stringent.

2. Will be more difficult and expensive to comply with
   drinking water regulations.

3. There is an even greater need for improved source water
   in the Delta – Need a multi-barrier approach, consistent
   with CALFED drinking water goal.
                                                         Slide 2
Source Water Quality Affects Drinking
  Water Quality and Public Health

  Bromide from
  seawater intrusion &
  TOC from Ag/natural          Treated Water
  sources                      Reservoir




             Water
             Treatment Plant
    Delta
                                               Distribution
                                               system

                                                          Slide 3
  Utilities Must Disinfect Water To Protect
                 Public Health
         Chemical Addition                              Sedimentation


 Raw Water                                                                       Filtration




                       Coagulation/Flocculation
Typical Water
  Treatment
   System
                                                             Treated Water




                                              Disinfection               Secondary Disinfection
                                                                            for Residuals
                Advanced Treatment
                (Ozone, Membranes, UV,
                GAC, Chlorine Dioxide)                                              Slide 4
How Disinfection By-products Are Formed
DBP precursors react with disinfectants to produce by-
products of human health concern . . .



Precursors
Bromide
                 +   Disinfectants
                     Ozone
                                        =   Byproducts
                                            Bromate
Organic Carbon       Chlorine               Trihalomethanes
                     Chloramines            Haloacetic Acids
                     Chlorine Dioxide       Other DBPs
                                                       Slide 5
Urban Agencies Must Meet Drinking
       Water Regulations



• USEPA regulates drinking water under the
  federal Safe Drinking Water Act.
• Source water quality is regulated under the
  federal Clean Water Act.
• Cal. DoHS has primacy (i.e. regulates CA
  systems)


                                                Slide 6
       DBPs and Health Effects



• Some DBPs are suspected human
  carcinogens (chronic exposure).
• Certain brominated DBPs suspected to cause
  birth defects (acute exposure)
• Only a few of the hundreds of DBPs have
  been characterized with regard to health
  effects (e.g., only 8% of ozone DBPs)

                                             Slide 7
  Utilities Must Balance Need to Disinfect
   with Need to Reduce DBP Formation




                Disinfection for     DBP Health
               pathogen control       Effects




• Enhanced Surface Water Treatment Rule – requires disinfection
• Disinfectants/Disinfection By-Products Rule – places limits on
  TTHM, HAA5, & Bromate
                                                          Slide 8
   DBP Formation Needs to Be Controlled
     Through a Combination of Efforts


Source Water        Treatment Plant                Distribution System



 Source Water                                            Distribution
                Precursor   Change Disinfectant
  Change or                                                System
                 Removal    or Application Point
 Management                                              Modifications




                                                                Slide 9
Water Quality Variability is Problematic

• Delta water has higher levels of bromide than 90-
  95% of all national drinking water sources
  – Bromide in the Delta ranges from 0.1 - 0.5 mg/L
  – TOC in the Delta ranges from 3 - 7 mg/L

• High bromide & TOC in Delta water requires urban
  agencies to use complicated treatment processes
  to ensure compliance with safe drinking water act
  regulations

• Treatment strategy used affects the types and
  concentrations of DBPs produced
                                                      Slide 10
Treatment Process Affects the Type and
   Concentration of DBPs Produced
                                                 TTHM                     HAA5                        Bromate      (2000 - 2004)
                          110
                                                              chlorine
                          100
                          90                       chlorine
   Concentration (ug/l)




                          80
                                      chloramine                         chlorine
                          70 chloramine                                                    chlorine                ozone
                          60 ozone                                                                                         Benchmark
                          50                                                        MIOX                chlorine           TTHM
                          40                                                                                               Benchmark
                          30                                                                                               HAA5
                          20
                          10                                                                                               Benchmark
                                                                                                                           Bromate
                            0




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                                MWD                                 CLAWA                                 VALLEJO


                                                                    Treatment Plant

 Mills Treatment Plant - ozone 4th quarter 2003. *Some missing data                                                               Slide 11
  Source Water Goals for Delta Water

• SWRCB 1991 Water Quality Control Plan
  – Found that agencies should “strive to obtain bromide
    levels of 0.15 mg/L or less (about 50 mg/L chloride in
    the Delta).”

• CALFED Water Quality Goal (CALFED ROD)
  –   50 µg/L of bromide (equivalent to <20 mg/L chloride)
  –   3.0 mg/L of TOC
  –   Or Equivalent Level of Public Health Protection
  –   Based on the 1998 CUWA expert panel
      recommendations

                                                      Slide 12
Delta Source Water Goals (continued)

• SWRCB 1995 Water Quality Control Plan
  – 250 mg/L chloride is about 850 µg/L bromide
  – 150 mg/L chloride is about 520 µg/L bromide
  – Nowhere near CALFED’s 50 µg/L bromide goal

• SWRCB has not yet adopted water quality
 objectives for drinking water protection
  – e.g., disinfection byproduct precursors, or
    pathogens

                                                  Slide 13
   Proposed Stage 2 DBP Rule Sets
Locational Running Annual Average for
             Compliance

• Promulgation expected in Summer 2005

• System-wide averaging will no longer be allowed

• Creates less room for error in process control for
  for agencies treating Delta water

• Creates more compliance risk with prolonged
  source water quality swings

• Regulation phases in through about 2011.
                                                  Slide 14
                     Conclusions
1. Disinfection Byproducts (DBPs) are a greater public
   health issue than in 1991. Additional DBPs likely to be
   regulated in future and DBP regulations will become
   more stringent.

2. Will be more difficult and expensive to comply with
   drinking water regulations.

3. Utilities cannot rely on treatment alone – need a multi-
   barrier approach, consistent with CALFED drinking
   water goal
      50 ug/L bromide and 3 mg/L TOC or an equivalent
      level of public health protection.
                                                         Slide 15