WHO NEEDS A BIG LAKE? WISCONSIN’S NEWEST SURFACE … · The City then began a comprehensive water...

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Inside this Issue: WHO NEEDS A BIG LAKE? WISCONSIN’S NEWEST SURFACE WATER TREATMENT PLANT Department of Natural Resources News • Public Service Commission News • Municipal Environmental Group • Committee Reports • WWA Nominations • A Century of Service SPRING ISSUE 2012 Wisconsin Water Association P.O. Box 635 Oak Creek, WI 53154 www.wiawwa.org A Section of the American Water Works Association

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Transcript of WHO NEEDS A BIG LAKE? WISCONSIN’S NEWEST SURFACE … · The City then began a comprehensive water...

  • Inside this Issue:

    WHO NEEDS A BIG LAKE?WISCONSIN’S NEWEST SURFACE WATER TREATMENT PLANT

    • Department of Natural Resources News • PublicServiceCommissionNews •MunicipalEnvironmentalGroup

    • CommitteeReports• WWANominations • ACenturyofService

    SPRING ISSUE 2012

    Wisconsin Water Association P.O. Box 635 Oak Creek, WI 53154 www.wiawwa.org A Section of the American Water Works Association

  • Wisconsin Water Association Spring 2012

    It is not often that a Wisconsin water utility builds a completely new surface water treatment plant. Even less often when the community is several hundred miles from a Great Lake, or even a good lake! The CityofAbbotsford is not located near a traditional surface water source; Abbotsford is located in the middle of Wisconsin, a great distance from large lakes or rivers. In fact, the City is located in an area of Wisconsin that has very challenging aquifer geology.

    The existing water system for the City of Abbotsford prior to this project consisted of 14 wells and two water treat-ment plants. The original water system was constructed in 1900 and was privately owned by a railroad company. In the 1940s, the City acquired the water system which at that time consisted of two very large dug wells and a bolted steel standpipe. The City bought a third dug well from a private milk dairy plant that had two vertical 12 foot di-ameter shafts and multiple hand dug 5 foot diameter tun-nels radiating as much as 100 feet from one of the shafts. All three of the dug wells and the standpipe are still in use today. The City installed additional watermain to serve the growing community and constructed two conventional drilled wells.

    Abbotsford’s water story took a turn in the late 1970s

    when the City experienced water shortages during a water drought. The City was able to drill seven additional wells during the 1970s to 2000. In 1997, the City constructed the Central WTP that treats water from 10 of the wells, and is constructed over the top of one of the dug wells. Shortly after this, the City constructed the Porky Creek WTP that treats four wells at a location northeast of the City. Both of these plants provide enhanced disinfection of the ground-water with ozone. In the early 2000s, water demand again was greater than the safe yield of the aquifer and the City added Wells No. 14 and 15, but the additional water added was less than 85 gallons per minute.

    The City then began a comprehensive water supply study that included additional groundwater wells with treatment, a pipeline from the Wisconsin River (32 miles east of Ab-botsford) and potable reuse (treatment) of treated wastewa-ter effluent from Elm Brook.

    With the scarcity of abundant groundwater, property owners in the Abbotsford area are very protective of the groundwater, and attempts to purchase land for well devel-opment was very difficult. The geology in Abbotsford con-sists of Precambrian granite bedrock close to the ground surface with overlying glacial till consisting of mainly clay.

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    By: Jon Strand, PE, LEED AP BD+C, Sr. PrincipalJana Nyhagen, PE

    SEH, Inc.

    Who Needs a Big Lake? Wisconsin’s Newest Surface Water Treatment Plant

    Chlorine contact tanks under construction.

    Water treatment equipment being moved into place.

  • Wisconsin Water Association Spring 2012

    Neither of these two aquifer materials is conducive for wa-ter storage. In rare instances, areas of sand and gravel can be found in the glacial till; however most of these areas have already been located and are used for water produc-tion. This granite bedrock is largely devoid of cracks or fractures in the immediate Abbotsford area.

    The City also explored a water pipeline from the Wausau area; however this alternative was later dismissed by the City due to overall cost. The communities along the route were not in immediate need for additional water supply, and the project was too costly for Abbotsford to finance alone.

    A water reuse alternative was also pursued by the City us-ing treated wastewater effluent from Elm Brook as a source of supply. The treatment process included a multi barrier filtration process with reverse osmosis as a final step. Ini-tially this alternative was favored by the City and local in-dustry, but was later dismissed as a public sentiment led the City Council to pursue a less direct water reuse system. The nearly two year long pilot study demonstrated that the wastewater could be treated to a pristine water quality.

    A breakthrough occurred when the City was able to ob-tain a well exploration agreement on 500 acres of privately owned land two miles east of the City. Twelve vertical col-lector wells were sited along granite fractures in the Porky Creek and Eau Pleine River valleys. Due to the proximity of the fractured granite formation to the ground surface, a full scale surface water treatment system was required.

    Along with finding a source of supply, two of the other significant challenges were finding adequate funding and

    procuring environmental permitting. Project funding was ultimately obtained by combining a $345,000 Wiscon-sin Department of Commerce Community Development Block Grant, a $970,000 EPA Grant, a $702,000 WDNR Safe Drinking Water Principal Forgiveness Loan (grant) and a USDA Rural Development combination $1.48 mil-lion dollar grant and $9.19 million dollar loan for a total project cost of $12.69 million. Water rates are projected to rise 85 percent to cover the loan portion; however the City is currently pursuing a higher increase for industrial water usage and a lower increase for the other rate classes. The basis for the higher industrial rate is the increased cost of supplying a higher volume of industrial water when small-er volumes of water for residential use are less expensive.

    The Eau Pleine WTP project operated under a mutually negotiated consent order with WDNR. Usually a consent order has a negative connotation and is perceived by the community as a burden. In Abbotsford's case, the City ac-tively pursued the consent order with WDNR. The consent order was used as vehicle by the City to keep elected of-ficials focused on the goals of the water project and it was used by WDNR to set a realistic time frame for the com-pleted project.

    The Wisconsin Public Service Commission authorized a water curtailment procedure that would be used if the aquifer level in the existing wells fell to critical levels. The curtailment procedure called for elimination of lawn water-ing, car washing, garden watering, and eventually, a reduc-tion in industrial water usage if the water in the wells fell to predetermined critical water levels. Fortunately, water levels did not fall to the point where industrial water usage would need to be curtailed.

    The areas where some of the twelve new collector wells were sited contained significant environmental permitting challenges, including wetlands, stream crossings, flood-

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    Filter room piping and conduit.

    Eau Pleine Water Treatment Plant.

  • Wisconsin Water Association Spring 2012

    plain areas, and most significantly, a protected turtle species.Wetland delineation, floodplain mapping, and a herpetolo-gist evaluation were required, along with extensive per-mit coordination. The turtle species required turtle barrier fencing and construction schedule phasing. The turtle is-sue proved to be one of the challenges for the project and also provided fodder for comic release during City meet-ings. Fortunately there were no turtles found during the construction phases. Had a turtle of this particular species wandered into the construction area and been mortally in-jured, the project would have stopped immediately. The regulations call for the deceased body to be cordoned off and an investigator called to determine the next course of action. The City water staff have now collected a number of turtle themed gifts that are on display at the WTP.

    The project was completed in two phases due to the imme-diate water shortage that the City was facing. Initially, four new wells were brought on line utilizing a temporary water treatment plant constructed within the semi trailer that was used for the water reuse pilot. The temporary WTP treated the water from the four wells, two at a time, on a 24/7 ba-sis. The WTP was connected to the City's SCADA system by the permanent fiber optic line that would serve the Eau Pleine WTP. Fortunately, these four wells had lower levels of iron, minimal manganese, and the well construction was such that temporary water filtration was not required. Poly-phosphate was used for iron sequestration and chlorine was used to provide 3-log Giardia and 4-log virus inactivation. To achieve and verify the proper chorine contact time, a residual chlorine analyzer was used in the temporary treat-ment plant along with a second chlorine analyzer in an entry point station located 4,300 feet away from the tem-porary treatment plant but prior to the first water customer. Fluoridation was also provided with the temporary treat-ment system. Piping and equipment from the temporary WTP was used in portions of the permanent project.

    As mentioned previously, the water treatment process for the twelve new vertical collector wells (500 GPM com-bined total) required surface water treatment. The water supply portion of the facility includes a raw water collec-tion system with twelve pitless units, two raw water meter-ing buildings and over two miles of raw water piping. After the water arrives at the Eau Pleine WTP, the water treat-ment plant process consists of air strippers to oxidize iron and remove radon, chemical rapid mix, four stage floccu-lation, inclined settling plates, trimedia gravity filtration, ultra violet disinfection, and chlorine disinfection. The multi-level process room allows for gravity flow through the plant from the top of the air strippers to the end of the clear wells.

    The gravity filtration system was provided by Tonka EquipmentCompany, and consists of two above grade surface water treatment units. The treatment units are con-structed of carbon steel, with many of the components constructed out of stainless steel. Following aeration (also provided by Tonka Equipment Company), these units in-corporate rapid mix, flocculation, sedimentation and filtra-tion. Stainless steel inclined plates are utilized for the sedi-mentation process and these plates are the key to achieving long filter runs. The gravity filters are made up of two cells per unit for backwashing purposes and include a tri-media filter system with anthracite on the upper layer followed by silica sand and garnet sand. The filters will also automati-cally backwash based on head loss.

    Trojan Technologies provided two Swift 2L12 units that are each capable of treating 1 MGD. The design dose is 27

    Filter end of flocculation, plate settling, and gravity filtration units.

    SCADA system screen.

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  • Wisconsin Water Association Spring 2012

    mJ/cm2, which is more than twice the dosage required for 3-log Giardia inactivation. An on-line UV transmittance monitor continuously checks the quality of the water that is going through the UV reactors. The UV reactors include the required light intensity sensors and an automatic wiper cleaning system for the quartz sleeves.

    The primary coagulant used is ferric chloride along with an ionic polymer secondary coagulant. Chlorine gas is used for chemical oxidation of iron, and sodium permanganate for manganese oxidation. Chlorine gas is also used for vi-rus and Giardia inactivation in the 74,000 gallon baffled chlorine contact tanks. A 100,000 gallon clear well area with two 500 GPM high service pumps is immediately downstream of the chlorine contact tanks. The plant is laid out to allow gravity flow through the treatment process. Fluoride/caustic soda addition is part of the final chemical adjustments to the treated water. Hawkins, Inc. supplied the chemical feed equipment.

    The plant contains redundant treatment process for a firm capacity of 500,000 GPD and a total capacity of 1,000,000 GPD. The entire water plant and twelve wells are protected with emergency backup power generation. Security fea-tures are included in the buildings and surrounding prop-erty that limit access and allow the City to continuously monitor the water treatment plant site and the well field site. The SCADA system will allow for unattended plant operations following the start up period. Because this is a new surface water treatment plant, the fa-cility must be staffed 24/7 for a period of at least 6 months before the system can operate in an unattended mode. Construction was substantially complete on December 30, 2011 which met the final condition of the consent order. The water treatment plant began continuous operation on January 30, 2012. The City has hired several water treat-ment plant operators as limited term employees to fulfill the 24/7, 6 month operating requirement.

    Water and energy conservation were part of the plant design with variable frequency drives utilized on most pumps. Backwash reclaim is utilized with settling tanks under the plant floor where decant water is introduced back into the treatment process and solids are settled a second time in lagoons with decant water introduced upstream of the collection wells by means of a constructed wetland and natural wetland areas.

    The Eau Pleine WTP project is the most ambitious project that the City of Abbotsford has ever undertaken in its his-tory. The project was completed under budget and within a very tight timeframe. This complex project benefitted from the cooperation of four different funding agencies, the Wisconsin Department of Natural Resources, and the Wis-consin Public Service Commission. The project was not without challenges during the planning stages, however, as the construction work began, the City came together to support the project, and now takes pride in the completed facility.

    Meter Building for pitless wells 25, 26 and 27.

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