FACILITIES PLAN EXECUTIVE SUMMARY

Document Sample
FACILITIES PLAN EXECUTIVE SUMMARY Powered By Docstoc
					   FACILITIES PLAN
 EXECUTIVE SUMMARY
                  for the

GENEVA WATER TREATMENT FACILITY

             prepared for the



    CITY OF GENEVA, ILLINOIS




               prepared by

              Black & Veatch
      101 N. Wacker Drive, Suite 1100
             Chicago, IL 60606

               October 2003
City of Geneva                                                       Water Treatment Facility
Facilities Plan                                                             October 22, 2003


EXECUTIVE SUMMARY

This Facilities Plan summarizes the results of engineering work conducted to determine
the best approach to satisfy the long-term water needs for the City of Geneva, IL. The
City of Geneva, in response to impending regulatory requirements and mounting public
concern for high quality drinking water, has decided to improve its water system. The
improved water system would consist of a series of wells (new and existing), new raw
water transmission mains, a new water treatment plant, and new finished water
transmission mains to convey the treated water to the distribution system.

The study consisted of evaluation of the population growth and water demands for the
Facilities Planning area, identification of the most suitable sources of raw water to meet
the needs of the City, comparison of the most feasible water treatment processes available
for the system, and review of the infrastructure improvements necessary for obtaining
and conveying raw water to the new treatment facility and finished water from the
treatment facility to the distribution system.

POPULATION AND WATER DEMANDS
Projections of future population and the corresponding water demands were developed to
determine the required long-term capacity of the improved water system. The City
provided population projections out to year 2020 and to ultimate buildout as listed in the
following table:
                                  Population Projections

                                                    Projections
          Service Area
                           2005       2010        2015     2020       Ultimate

           Residential     21,600    24,200       24,200   24,200      24,200

         Non-Residential   15,000    17,000       19,200   21,200      21,200
        Total Population
                           36,600    41,200       43,400   45,400      45,400
          Equivalent

The projected water demands were estimated using historical data that correlated metered
water sales and population. Geneva’s average water use is 76 gallons of water per capita
per day. For the maximum daily water demand, historical data indicates the ratio of
maximum daily demand (MDD) to average daily demand (ADD) is 1.9 for Geneva. The
projected water demands for the planning area were calculated as follows:

                                              1
City of Geneva                                                          Water Treatment Facility
Facilities Plan                                                                October 22, 2003




                           Projection of Daily Water Demand

   CITY OF GENEVA                        2005       2010      2015      2020     Ultimate

   Total Population Equivalent          36,600      41,200   43,400    45,400      45,400
   Avg Daily Demand, mgd                 3.41        3.85     4.06      4.26        4.26
   MDD/ADD Ratio                          1.9        1.9      1.9        1.9         1.9
   Maximum Daily Demand, mgd             6.48        7.32     7.71      8.09        8.09
   Selected Design Capacity, mgd                                                     8.0


With these projections, it was recommended that the water treatment facility be designed
for a peak capacity of 8 mgd.

WATER SUPPLY
To meet the projected water demands, several sources of water were evaluated: bedrock
(deep) aquifer, shallow aquifer, and the Fox River. Currently, the City uses water from
both the shallow and deep aquifers, with minimal treatment.

The bedrock (deep) aquifer in northeastern Illinois was estimated by the Illinois State
Water Survey (ISWS) to have a safe yield of 46 to 65 mgd. In 2000, the reported
withdrawal from the bedrock aquifer was 71.5 mgd, which suggests that more water is
being withdrawn from the aquifer than is being recharged. The groundwater in this deep
aquifer contains radium at concentrations that exceed the current regulatory standard of 5
picocuries per liter (pCi/L). Therefore, if this aquifer is used, it must be treated to reduce
the radium concentration.

According to a study conducted in 1999, the long-term safe yield from the shallow
aquifer was estimated to be 7 mgd. Currently, the communities of St. Charles, Geneva,
and Batavia withdraw water from the shallow aquifer. In 2002, Black & Veatch updated
the computer model of the shallow aquifer and projected a higher long-term safe yield of
11 mgd. St. Charles and Batavia are expected to use approximately 7.9 mgd from this
aquifer on an average basis; therefore, an average withdrawal of 3.1 mgd is available to
Geneva. This average withdrawal corresponds to a peak day withdrawal capacity of 6.2
mgd. The computer model that simulated wellfield production for the proposed water
treatment facility was used to determine preliminary placement and production capacity

                                                2
City of Geneva                                                        Water Treatment Facility
Facilities Plan                                                              October 22, 2003


of the proposed shallow wells. The groundwater from the shallow aquifer contains
elevated levels of iron and manganese that must be removed prior to distribution as is
currently accomplished at the City’s existing shallow well water treatment facility.

Withdrawal of water from the Fox River is regulated by the Illinois Department of
Natural Resources (IDNR), which requires that a permit be obtained before constructing
water supply intakes along the river. IDNR does not specify an allowable withdrawal
rate but does specify that withdrawals must cease when the river reaches its 7Q10 low
flow (the lowest average flow over a seven-day period expected to occur once every ten
years). Although the Fox River does not contain elevated levels of radium, the hardness
levels in the river water are comparable to those found in both aquifer supplies, also the
regulatory standards for treating surface water are much more stringent than for treating
groundwater because of the potential for waterborne pathogens (Giardia,
Cryptosporidium, E coli, etc.).

The water from each of the three sources contains elevated levels of hardness (calcium
and magnesium) that contribute to scaling in the distribution system and in individual
household plumbing. High hardness levels also tend to dry the skin during bathing.
Currently approximately 70 percent of the City’s water customers utilize home water
softening systems. Hardness is not a regulated constituent in drinking water, but a
secondary standard (non-enforceable) is in place to minimize the problems stated above.

Because of the limited supply of shallow aquifer water, either the deep aquifer or the Fox
River must be used to supplement the total supply for the Geneva water treatment
facility. Because of the distance of the proposed treatment facility site from the Fox
River and the more stringent regulatory standards applicable to treating surface water, it
is recommended that the City continue to utilize a combination of shallow and deep
aquifer supplies. If the quantity or quality of the water from either or both aquifers
declines to a point that future water demands can no longer be met, it may be necessary to
obtain water from the Fox River.

WATER TREATMENT
The most feasible treatment options for meeting the applicable drinking water standards
and providing high quality water to the City of Geneva are membrane softening and lime
softening. Both technologies are capable of removing hardness and radium with similar
efficiency, making either technology a feasible choice for the Geneva water treatment
facility.

                                             3
City of Geneva                                                          Water Treatment Facility
Facilities Plan                                                                October 22, 2003




Membrane Softening
Membrane softening utilizes reverse osmosis (RO) or nanofiltration (NF) membranes to
remove dissolved constituents from the raw water. Because of the high removal rates of
these dissolved constituents, the finished water quality far exceeds the desired hardness.
Therefore, a portion of the influent raw water is typically bypassed around the
membranes and blended with treated water from the membrane units. The percentage of
water that bypasses the membrane would be adjusted depending on the influent raw water
quality and the desired effluent quality.

Softening membranes are susceptible to fouling by a variety of constituents. One of the
most common types of fouling in softening applications is scaling of the membrane by
the iron and manganese present in the raw water. Raw water from the City’s shallow
wells contains these constituents at concentrations that require removal ahead of the
membrane units. Iron and manganese are typically removed by a combination of
oxidation and filtration (either sand filtration or membrane filtration). It is anticipated
that the deep well supply with its lower levels of iron and manganese will not require
pretreatment for these constituents ahead of the membrane units.

Lime Softening
Lime softening utilizes chemical precipitation to remove calcium, magnesium, and other
dissolved constituents such as radium. In the lime softening process, a combination of
lime, soda ash, carbon dioxide, and other coagulants is added to the raw water to facilitate
the precipitation of calcium and magnesium. Radium is removed from the water by the
same mechanism. The settled solids are then removed from the treatment process. After
softening, the water is filtered to remove any solids that have carried over from the
settling basins.

Residuals Management
Both membrane softening and lime softening produce residuals that require disposal.
Operation of the membrane units generates a certain quantity of water that contains high
concentrations of dissolved constituents. This water, called membrane concentrate, must
be disposed of by discharging either directly to a receiving water (river, lake, etc.) or to a
sanitary sewer system. For Geneva, the only available options are discharge to the Fox
River through the storm sewer system or to Geneva's wastewater treatment plant through
the sanitary sewer system. According to Illinois Environmental Protection Agency
(IEPA) policy, the Geneva wastewater treatment plant is considered best available

                                              4
City of Geneva                                                          Water Treatment Facility
Facilities Plan                                                                October 22, 2003


treatment for the membrane concentrate due to potential removal of barium and radium.
In addition, recent anti-degradation regulations promulgated by the IEPA stipulate that in
order for a direct discharge of a new waste stream to a receiving water to be allowed, it
must be proven that treatment of the waste stream by the best available treatment would
not be possible. This means that discharge of the membrane concentrate to Geneva’s
sanitary sewer system must be proven to be infeasible. Since an evaluation of the
potential impacts of the membrane concentrate on the sanitary system concluded that the
residuals would have no significant impact on the sewer system or the wastewater
treatment plant, it was decided not to pursue the possibility of direct discharge of the
waste stream to the Fox River.

Lime softening produces solid residuals that contain calcium carbonate and magnesium
carbonate as well as other constituents. In Geneva, the lime softening residuals would
also contain a certain quantity of radium. The residuals generated by the lime softening
process are typically disposed of either by application to agricultural land or in a landfill.
It is estimated that the radium concentrations in the residuals would not be high enough
to prohibit land application or disposal in a Subtitle D (non-hazardous waste) landfill.

TREATMENT FACILITY SITING
Two potential sites for development of the proposed Geneva water treatment facility were
identified: (1) the 33-acre Peck/Keslinger site, which is on the southwest corner of
intersection of Peck Road and Keslinger Road and (2) the City-owned 8-acre Kaneville
site located north of Kaneville Road. After evaluating both sites in terms of technical and
economic feasibility, public acceptance, zoning, road access, and proximity to existing
and new wells, it was determined that the Peck/Keslinger site was the preferred location
for the new Geneva water treatment facility.

WELL SITING AND SELECTION
To supply the necessary quantity of water to meet peak demands, additional wells in both
the shallow and deep aquifer will be needed. The combined installed capacity of the
City’s existing three shallow aquifer wells and four bedrock (deep) aquifer wells is 11.9
mgd. Modeling of the shallow aquifer performed as a part of a previous study indicates
that the capacity of the shallow wells is substantially reduced when all shallow wells are
operated simultaneously. This reduction in well capacity is due to the influence that
neighboring wells have on each other.



                                              5
City of Geneva                                                       Water Treatment Facility
Facilities Plan                                                             October 22, 2003


Three of the four existing deep wells are located along the Fox River. Because both of
the proposed water treatment facility sites are several miles from the river, the cost to
convey water from these wells to the plant sites would be greater than the cost to develop
new wells closer to the treatment facilities. Therefore, in order to meet the projected 8
mgd peak demand, several new wells (both shallow and deep) should be constructed, and
the three existing deep wells near the Fox River should be taken out of service.

The three existing shallow wells (G8, G9, G10) have a combined maximum production
rate of 3.2 mgd, and the existing deep well (G6), which is recommended to remain in
service has a maximum production rate of 1.6 mgd. Thus, the maximum total production
rate of the existing wells available to the new treatment facility is 4.8 mgd. Use of the
lime softening process would require a firm well capacity of 8 mgd; use of the membrane
softening process would require a firm supply capacity of 9 mgd because of the residuals
flow generated. Therefore, additional wells will be required regardless of the process
selected. In either case, three new deep wells will be developed, and one additional
shallow well would be developed in the event that membrane softening is selected.

The siting of the new deep wells was based on a minimum spacing of 1,500 feet between
wells. The siting of new shallow wells was based on modeling of the shallow aquifer
while maintaining a minimum spacing of 3,000 feet. An economic analysis was
performed to establish the recommended well sites, taking into account well
development, land acquisition, raw water transmission, and electricity costs.
Recommended well sites are shown on Figures VII-3.

RAW WATER TRANSMISSION
New raw water transmission mains will be required to convey raw water from the new
and the existing wells to the new water treatment facility. Because of the difference in
water quality between the two aquifers, it is recommended that the two supplies be
conveyed to the membrane softening facilities in separate transmission mains to reduce
the costs associated with pretreatment of the shallow well water for iron and manganese
removal. The deep aquifer water does not need this pretreatment and can be conveyed
directly to the membrane softening units. Where appropriate, the separate transmission
mains would be located in the vicinity of the existing shallow and deep wells to best
utilize the existing infrastructure and easements. The lime softening process does not
require pretreatment for iron and manganese and therefore, does not require separation of
the aquifer supplies. Recommended raw water transmission mains are shown in Figure
VIII-1.

                                            6
City of Geneva                                                      Water Treatment Facility
Facilities Plan                                                            October 22, 2003




FINISHED WATER TRANSMISSION
Treated water from the new water treatment facility will be conveyed in a single finished
water transmission main to the City’s distribution system connection point along Randall
Road. A 12-inch main will also extend from the facility site to a connection point along
Lewis Road as well. The recommended finished water transmission mains are shown on
Figure IX-1.




                                            9
City of Geneva                                                          Water Treatment Facility
Facilities Plan                                                                October 22, 2003


OPINION OF PROBABLE COSTS
The economic comparison of the opinion of the probable costs for the two system
alternatives is summarized in the following table:
                                   Opinion of Probable Costs

                                                          Membrane             Lime
                        Item
                                                          Softening1         Softening1
 Water Supply
    Well Improvements                                     $3,103,000         $2,828,000
    Raw Water Transmission Improvements                   $1,071,000          $715,000
 Water Treatment Facility                                 $14,916,000        $15,092,000
 Finished Water Transmission Improvements                 $1,450,000         $1,450,000
 Construction Cost Subtotal                               $20,540,000        $20,085,000
 Treatment Site Acquisition and Development                $1,911,000         $1,911,000
 Engineering (Design, Construction Services)              $3,210,000         $3,140,000
 Total Probable Project Cost                              $25,661,000        $25,136,000
 Initial Annual O&M Cost                                   $1,323,000         $1,380,000
 Present Worth Of Annual O&M Costs2                       $27,440,000        $27,610,000
 Total Present Worth Project Costs2                       $53,101,000        $52,746,000
 Equivalent Annual Cost2                                  $3,570,000         $3,550,000
1) The costs listed above include contingency.
2) Assume 3% interest rate and 20 year planning period.


As indicated in the table above, the project cost for the membrane softening is
approximately 2% higher than that for lime softening, while the membrane softening
annual O&M cost is approximately 4% lower than that for lime softening. The resulting
differences in present worth costs and equivalent annual costs for the two alternatives are
less than 1%. These planning level costs (project, O&M, and present worth) are within
the level of estimating accuracy and for the purposes of this evaluation are considered
equal.




                                                 11
City of Geneva                                                             Water Treatment Facility
Facilities Plan                                                                   October 22, 2003



RECOMMENDED PLAN
Based on the economic and non-economic evaluations completed in this study, the
recommended plan for the Geneva water treatment facility is as follows:

Water Treatment
With the costs of the membrane and lime softening process alternatives being essentially
equivalent, it is recommended that membrane softening be implemented at the new
Geneva water treatment facility, based on the following advantages:

    •   Greater potential for meeting future regulatory requirements.
    •   Greater potential for future reduction in plant operating staff.
    •   Reduced residual management cost and effort.
    •   Greater acceptance of the aesthetics of the facilities due to lack of on-site residual
        lagoon dewatering facilities.
    •   Greater acceptance of building and process aesthetics.
    •   Reduced truck traffic to and from the treatment facility.
    •   Greater flexibility in phasing and future expansion.
    •   Greater security with indoor location of treatment process.
    •   Smaller land requirements, allowing more space for other uses.

A schematic of the recommended treatment process is shown on Figure XI-1.

Water Supply and Raw Water Transmission
Based on a detailed evaluation, it is recommended that the City install three new deep
wells and one new shallow well to supplement the existing three shallow wells and one
deep well to provide a total firm capacity of 9 mgd. The three existing deep wells near
the Fox River should be taken out of service and used for emergency supply only. It is
also recommended that the water from the shallow and deep aquifers be routed to the new
water treatment facility in separate transmission mains to reduce pretreatment costs.

Finished Water Transmission
A 24-inch finished water transmission main is recommended to convey water from the
new treatment facility to Geneva’s existing water distribution system. The transmission
main would follow Peck Road south to its intersection with Kaneville Road, and continue
northeast along Kaneville Road to Randall Road, approximately 1,000 feet south of the
intersection of Randall Road and Keslinger Road.


                                              12
City of Geneva                                                       Water Treatment Facility
Facilities Plan                                                             October 22, 2003




Construction Implementation
Considering the City’s growth rate and associated increase in water demands, it is
recommended that the initial construction of the well field, raw water transmission, water
treatment facility, and the finished water transmission main provide the full capacity for
the ultimate build out of the community. Because of the timing of the projected water
demands increases, phased implementation will not result in any significant savings.
However, the City should proceed purchase the property and easements for the future
shallow wells and raw water transmission mains identified later in this report. It is
recommended that the City develop future Shallow Well “A” to the point that it can be
permitted by the IEPA. The installation of the production well, well pump and motor,
and associated raw water transmission main would be phased for future improvements if
water demands increase beyond earlier projections.




                                            13