Project Category: Water

Capital Efficiency Plan™ for Avon, MA

Tata & Howard recently completed a Capital Efficiency Plan™ for the Town of Avon, MA.  As part of the project, Tata & Howard updated and verified the Town’s existing hydraulic model. The work included the completion of fire flow tests throughout the Town and allocation of demands using up-to-date billing and parcel data. The Capital Efficiency Plan™ identified and prioritized areas for improvement within the distribution system.

Our services included evaluating the condition of the existing distribution system infrastructure to determine the adequacy of meeting present and future demands, assessing and prioritizing system improvements, reviewing and evaluating typical fire flows throughout the system, creating a pipe asset management rating system, and recommending improvements to the distribution system. Recommendations included installation of two replacement wells, conducting an interconnection study, rehabilitation of the Page Street Tank, and phased distribution system improvements.

The hydraulic model was also verified under an Extended Period Simulation (EPS), which considers changes in the distribution system over time. The EPS will be used to evaluate tank operating ranges and modifications to the well operating conditions.

Capital Efficiency Plan™ for Norwalk, CT First Taxing District

Tata & Howard, Inc. was retained by the First District Water Department (FDWD) to complete a Capital Efficiency Plan™ for the First District water system in the City of Norwalk, CT.  Areas of the water distribution system in need of rehabilitation, repair, or replacement, were identified and improvements were prioritized to make the most efficient use of the FDWD’s capital budget. The study evaluated the existing water infrastructure including water transmission and distribution piping and appurtenances. In addition, water storage needs were evaluated and prioritized.

Tata & Howard evaluated the water distribution system using the Three Circle Approach, which consists of evaluation criteria including a system hydraulic evaluation, a critical component assessment, and asset management considerations.

Hydraulic improvements included recommendations that would strengthen the transmission capabilities of the system or provide an ISO recommended fire flow to a certain area. Priority 2 recommendations were identified as part of a system-wide evaluation to improve estimated needed fire flows and system looping.


A critical component assessment was performed for the water distribution system to evaluate the impact of potential water main failures on the system.  The critical component assessment includes identification of critical areas served, critical water mains, and the need for redundant mains.  Critical areas served were identified by the FDWD and include water department facilities, medical facilities, schools, and business districts. Critical water mains include primary transmission lines as well as water mains that cross over major highways, rivers, and railroad tracks. Factors that affected the decision to replace or rehabilitate a water main include break history, material, age, diameter, soil conditions, water quality, and pressure.

An asset management assessment was completed for the system. A number of factors are considered in the ratings including break history, material, age, diameter, soil conditions, water quality, and pressure, and these factors affect the decision to replace or rehabilitate a water main.

Utilizing the Three Circle Approach, improvements were recommended and prioritized based on the aforementioned criteria. Phase I improvements include any recommended improvements that fall into all three circles and are therefore hydraulically deficient, critical, and have a high asset management score.  There are approximately 16,300 linear feet of new main in the Phase I recommended improvements. Phase II improvements include any recommended improvements that fall into two of the circles. There are approximately 81,400 linear feet of new main in the Phase IIa and Phase IIb recommended improvements. Phase III recommendations include any recommended improvements that are needed hydraulically or that have a high asset management score indicating poor condition. The Phase IIIa and Phase IIIb include approximately 157,000 linear feet of new main. In addition, recommendations included soil testing for corrosivity prior to ductile water main installation, implementation of a unidirectional flushing program, and annual updating of the hydraulic model.

Capital Efficiency Plan™ and Water System Master Plan, Attleboro, MA

Tata & Howard, Inc. was retained by the City of Attleboro to complete a Capital Efficiency Plan™ and Water System Master Plan for the Attleboro water system.  The purpose of the Capital Efficiency Plan™ portion of the project was to identify areas of the water distribution system in need of rehabilitation, repair, or replacement, and to prioritize improvements to make the most efficient use of the City’s capital budget. The Water System Master Plan portion of the project created an inventory of the existing above ground water infrastructure assets including wells, pumping and treatment facilities, and water storage tanks. The inventory can be used to track maintenance, repair, and replacement work.  Basin safe yields were reviewed and compared to projected demands to evaluate the adequacy of sources of supply. In addition, the project included creation of an extended period simulation (EPS) hydraulic model which can be used to analyze the system and account for changes over time.

An asset management assessment was completed for the system. Several factors are considered in the assessment including age, material, diameter, break history, soil conditions, water quality, pressure, and whether the main was installed poorly.  These factors affect the decision to replace or rehabilitate a water main.  Using our asset management rating approach, each water main in the system was assigned a rating based on these factors. Utilizing the Three Circles Approach, improvements were recommended and prioritized based on the aforementioned criteria. Recommended improvements include the following:

  • Three phases of water main replacement projects;
  • A Water Quality and System Optimization Study to evaluate ways the City can lower the water age in the storage tank;
  • A study to evaluate improvements to maximize available yield;
  • Collection and maintenance of data on water main failures as well as pipe crushing results from water mains that have failed;
  • Testing of soil for corrosivity prior to installation of new ductile iron water mains;
  • Implementation of a Unidirectional Flushing Program; and
  • Minor repairs and security improvements to address deficiencies in the City’s above ground assets.

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Pilot Testing for Iron and Manganese Removal in Barnstable, MA

Due to elevated levels of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), 1,4 Dioxane, and iron and manganese in the three drinking water production wells at the Maher Water Treatment Facility, the Town of Barnstable is proceeding with design and construction of upgrades at the facility to treat for these constituents.

Pilot testing includes carbon, Greensand, and LayneOx filters

The Town of Barnstable is currently conducting pilot testing at the site to determine the required design parameters, treatment process effectiveness, and best technology to achieve the desired treated water.  Treatment processes associated with pilot testing include GreensandPlus and LayneOx for removal of iron and manganese, advanced oxidation (ultraviolet light with hydrogen peroxide) for removal of 1,4-dioxane, and granular activated carbon (GAC) for removal of PFOS and PFOA.  Treatment for 1,4 Dioxane is the primary goal of the pilot test in order to meet the requirements of the Massachusetts Department of Environmental Protection (MassDEP) New Technology Approval process.

The MassDEP has confirmed that pilot testing of GAC filtration at the Maher facility is not a statutory requirement due to the current use of this water treatment technology at the Town’s Mary Dunn Wells and the availability of current water quality data for treatment of PFOS/PFOA within the same water system.  However, the Town has decided to include GAC filtration with pilot testing of advanced oxidation and iron and manganese removal to evaluate the performance of all proposed treatment processes operating together.

UV reactor for pilot test

Pilot testing is being conducted by Blueleaf, Inc. as a sub-consultant to Tata & Howard, Inc.  Pilot testing was completed in 2017.

 

 

 

 

Water Main in Palmer, MA, funded by a CDBG

Tata & Howard provided design of 1,400 linear feet of 12-inch diameter water main on Griffin Street, High Street, and Stewart Street. Work included the preparation of design plans and specifications, hydraulic modeling to determine main size, and letter and cost estimate to the Palmer Community Development Department. Tata & Howard also provided construction administration and resident observation services. The project was funded by a USDA Rural Development Community Development Block Grant (CDBG).

 

Water Treatment Plant in Concord, MA

This project included construction of a 1.5 mgd capacity water treatment facility to treat potable water pumped from the existing Deaconess Well. The water treatment facility consisted of six vertical LayneOx pressure filters. The work also included demolition of the existing well pumping station and construction of a well pump vault with vertical turbine pump over the existing well, and completion of a SCADA system design to monitor and control the water treatment facility and well station.

Background:

Faced with increasing iron and manganese concentrations at two of its existing wells, Concord Public Works (CPW) decided that treatment was required.  Several treatment options were evaluated, with the most cost effective option being pressure filtration.  Piloting pitted manganese greensand against LayneOx, a proprietary media marketed by Layne-Christensen Company utilized in other parts of the country, but not in New England. In addition to proving its effectiveness in iron and manganese removal, “new technology approval” was obtained for the media from MassDEP. Although piloting showed LayneOx to have an advantage over greensand during testing at the Deaconess well site, the Town’s Procurement Office was reluctant to allow CPW to solely specify a proprietary media. Differences in piping and chemical requirements for both filter processes precluded a design that could have served either treatment system. Hence, a pre-purchase equipment bid was developed specifying both systems.

An additional challenge to treating the water was designing the treatment facility itself, whose architecture had to “blend in” with the bucolic and well healed character of the surrounding neighborhood. The Town requested that we provide three options simulating different themes; a barn, railroad station and a Richardsonian Romanesque style structure similar to the Chestnut Hill pump station. Our Architect provided renderings of the three options along with estimated costs and lists of pros and cons. After several meetings and input from various interested parties the Town chose the barn theme.

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Water Treatment Plant in North Chelmsford, MA

Tata & Howard completed a test evaluation and design report for the Bomil Well site comparing ultrafiltration using ozone and chlorine dioxide as oxidants. The report also evaluated several coagulant aids to treat the organic color in the water. The design report became the basis for the 2.5 mgd water treatment facility designed by Tata & Howard. The facility uses membrane filtration with chlorine dioxide for treatment.  Construction administration was also provided by Tata & Howard.

Iron and Manganese Removal Using Greensand Pressure Filtration


Tata & Howard conducted a Water Quality Study that reviewed the Town of North Attleboro, Massachusett’s corrosion control practices, and evaluated changes in quality, specifically the increased levels of iron and manganese. The manganese concentrations in these wells had consistently increased during the past decade. The pilot treatment study for manganese removal with greensand pressure filtration was conducted at the Kelley Wells 1 and 2 and was a success. Tata & Howard completed the design of the 2.0 mgd capacity treatment facility and provided engineering services during the construction of the facility.

The design included the installation of a SCADA system for monitoring and control of the treatment facility and two well pump stations.  A second operator work station was installed at the remote Water Department office which allowed both monitoring and control of the treatment facilities from this remote site.  In addition, the operator work station was linked to the existing Autocon SCADA system which continued to monitor and control the remaining water system pumping stations and storage tanks and provide tank level signals for the establishment of start/stop setpoint controls for the new treatment facility and associated wells.

 

 

 

 

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Trinity Ave. Chemical Feed Pump Station, Grafton, MA

Tata & Howard provided engineering services for permitting, design, and bidding of the 1.3 mgd chemical injection Trinity Avenue Pump Station at the Trinity Avenue Wellfield.  The project included an evaluation of alternatives for the access road including installation of a bridge or an open bottomed culvert; assistance with the preparation of permanent easements for the installation of utilities and roadway to the well site; preparation and submittal of an NOI to the Grafton Conservation Commission.  The design included an access road, bailey bridge with abutments, double wythe block building, interior concrete painted block with wood truss roof and asphaltic shingles, installation of three (3) submersible pumps and pitless adaptors, approximately 1,800 linear feet of 6-inch and 12-inch water main, emergency liquid propane tanks and generator, instrumentation and controls, a SCADA system for the pump station and wells, and a 24-inch transmission main for 4-log removal. Security included chain link fence, gates, locks, intrusion alarms, and lighting.  Tata & Howard also assisted Owner with the coordination of the installation of three phase power to site.  Chemical feed at the station includes KOH for pH adjustment and chlorine gas for disinfection.  Standby power was included in an outdoor enclosure. The project is currently under construction and is expected to be completed by the end of 2017.

Manganese Filtration Using Biological Pressure Filtration

The Home Farm Water Treatment Plant (WTP) in Shrewsbury, Massachusetts was originally constructed in 1989. Although the WTP is still fully functional, its treatment capabilities are limited to chemical addition and air strippers for VOC removal, and the plant is capable of treating 6.0 million gallons per day (mgd). Manganese is present at all Home Farm wells, with widely varying levels from a low 0.03 parts per million (ppm) to a high 0.7 ppm. The existing treatment plant sequesters manganese, but does not have the ability to remove it from finished water.

Pilot test setup

Three treatment methodologies were piloted. The first two were greensand and pyrolucite, both commonly implemented catalytic media options for removing manganese and iron. The third was Mangazur®, a new technology. Mangazur® filter media contains the microscopic organism leptothrix ochracea, which consumes manganese and is naturally occurring in groundwater. Through consumption, the microbes oxidize the manganese to a state where it can precipitate onto the media. Unlike other media, Mangazur® does not require regeneration due to the continuous growth of microbes within the filter. Mangazur® technology also does not require chemical addition for pre-oxidation, minimizing the amount of chemical required for the plant.

Pilot testing for the biological treatment was performed over five one-week trials. Test parameters included a long shut-down on the filters, adding pre-oxidant, and adjusting pH or dissolved oxygen. The results of the testing indicated that although the Mangazur® does require a correct dissolved oxygen level and pH, it does not require a pre-oxidant, making the only chemical addition necessary for pretreatment potassium hydroxide for pH adjustment. Filter backwash efficiency is also a major benefit of the Mangazur® technology for the Home Farm application. With loading rates twice that of traditional catalytic media and filter runs exceeding 96 hours; the Town would only need to backwash the four filters once every four days rather than eight filters every day, saving a significant amount of water. The backwash flow rate and duration are also significantly lower for Mangazur® filters than for other traditional filter options. The results of the pilot tests indicated that all technologies were viable options to reduce manganese levels below 0.05 ppm; however, the biological treatment was the most efficient and attractive option.

Ground breaking on the new WTP took place in July 2017.

Initially, the Town was only considering constructing filters along with the required backwash holding tanks in a new building and utilizing the chemical feed systems in the existing treatment facility. However, as the project progressed it was determined that it would be more cost effective to replace the existing aging air strippers rather than to continue to rehabilitate them, and eliminate the need to re-pipe the flow since the existing strippers added too much dissolved oxygen prior to the biological units. Since the existing chemical feed equipment in the plant is aging and the existing building itself was also in need of rehabilitation, the decision was made to construct an entirely new standalone 7.0 mgd facility. The new facility also contains three deep bubble aerators for VOC removal.

While Mangazur® technology has been approved in one other municipality in Massachusetts, there are few treatment plants in the northeast using this technology, and of those treatment plants, none have a design capacity above 5.0 mgd.  Home Farm has a much higher design capacity and will be the largest Mangazur® water treatment plant in the northeast once completed.  The Mangazur® filters at Home Farm will have the second highest design capacity in the country, after a 26.0 mgd treatment plant in Lake Havasu City, Arizona.

 

 

You may download the complete whitepaper by clicking here.

 

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