Construction Archives - Tata & Howard

Iron and Manganese Removal in West Brookfield, MA

The West Brookfield Water Department (WBWD) is taking an important step toward improving drinking water quality and protecting public health with planned upgrades to the Leland Road Pump Station. The project will introduce new treatment to remove iron and manganese from the town’s groundwater supply, helping ensure compliance with regulatory standards while improving the overall quality and reliability of drinking water for the community.

Tata & Howard has been contracted to provide design, permitting, and bidding services for the project, which will add a new filtration facility at the Leland Road well site.

Addressing Iron and Manganese

WBWD’s water system relies on five groundwater wells that serve approximately 2,555 residents. Well 01G supplies the Ware Point Road Treatment Facility, while Wells 03G through 06G feed the Leland Road Pump Station before entering the town’s distribution system. Currently, the Leland Road Pump Station provides chemical treatment using potassium hydroxide for pH adjustment and calcium hypochlorite tablets for oxidation and disinfection. However, the facility does not include filtration treatment.

Recent water quality monitoring has shown increasing levels of iron and manganese in several of the wells serving the Leland Road facility. Iron concentrations have exceeded the Secondary Maximum Contaminant Level (SMCL) of 0.3 milligrams per liter (mg/L), while manganese concentrations have consistently exceeded the SMCL of 0.05 mg/L.

Additionally, manganese has exceeded the health advisory of 0.3 mg/L. As a result, the Massachusetts Department of Environmental Protection is requiring the Town to install a treatment system to address iron and manganese levels.

Why Manganese Removal Is Important

Iron and manganese are naturally occurring elements often found in groundwater. While they are traditionally classified as secondary contaminants, manganese is increasingly recognized as an emerging contaminant with potential health implications.

Research has shown that prolonged exposure to elevated manganese levels may impact neurological development, particularly in infants and young children. For this reason, the U.S. Environmental Protection Agency has established a lifetime health advisory of 0.3 mg/L for manganese.

Addressing these contaminants will not only improve the appearance and taste of the town’s drinking water but also ensure compliance with evolving health guidance and regulatory requirements.

A Treatment Solution for the Future

To address these water quality challenges, WBWD plans to install a GreensandPlus™ pressure filtration system at the Leland Road Pump Station. This technology is widely used for removing iron and manganese from groundwater supplies.

The new treatment facility will be housed in a separate building constructed adjacent to the existing pump station. The building will include three 7-foot diameter GreensandPlus™ filter vessels designed to treat water from Wells 03G through 06G.

Additional upgrades will include improvements to chemical feed systems, well pump upgrades, and enhancements to the Supervisory Control and Data Acquisition (SCADA) system for improved monitoring and operational control.

Pilot testing previously conducted for the site demonstrated that GreensandPlus™ filtration can reliably reduce iron and manganese concentrations to below treatment goals of 0.1 mg/L for iron and 0.025 mg/L for manganese, providing a long-term solution for maintaining water quality.

Funding Support Makes the Project Possible

For a small community like West Brookfield, major infrastructure investments can be difficult to fund through local water rates alone. The Leland Road Pump Station upgrade is estimated to cost approximately $6.24 million, a significant investment for a system with only about 1,000 water customers.

The Town is receiving important financial assistance to help make the project possible. The project will receive funding through the Drinking Water State Revolving Fund (SRF) program, which provides low-interest loans to communities for critical water infrastructure projects. The loan is expected to carry a two percent interest rate with potential principal forgiveness, reducing the financial burden on the community.

In addition, the project has secured $1 million in Congressionally Directed Spending (CDS) funding, as well as a $500,000 Emerging Contaminants in Small or Disadvantaged Communities (EC-SDC) grant to support the treatment improvements.

Financial assistance of this kind is essential for small water systems. As noted by the Town, without additional funding beyond the basic SRF loan, the cost of constructing the treatment facility would place a significant strain on the water department’s budget and could require major water rate increases.

Protecting West Brookfield’s Water Supply

Once completed, the Leland Road Pump Station upgrade will significantly improve drinking water quality for West Brookfield residents by removing iron and manganese and ensuring compliance with state guidelines. More importantly, the project will provide the community with a long-term solution that strengthens the reliability and safety of its drinking water system for years to come.

Water Treatment Plant, Amherst, MA

amherst-wtp-exterior Tata & Howard contracted with the Town of Amherst for design, permitting, bidding, and construction administration of the 1.5 million gallon per day (MGD) Centennial Water Treatment Plant (WTP) to treat surface water from the Pelham Reservoir System. The existing Centennial WTP, located in the Town of Pelham but supplying the Amherst Public Water System, has a history of issues with turbidity, color, and disinfection byproducts in the form of total trihalomethanes (TTHM) and haloacetic acids (HAA5) because of high levels of organics in the Pelham Reservoir System. Due to the age and condition of the existing WTP, the filters which were the primary treatment process at the existing WTP were no longer effective at removing organics, leading to a decrease in finished water quality and total WTP capacity. The existing Centennial WTP has been offline since 2018 due to water quality, as well as infrastructure concerns related to a lightning strike which impacted pumping equipment and communications at the Centennial Water Treatment Plant’s raw water pump station.

Based on the results of the pilot study performed by the Town of Amherst, Tata & Howard completed design of the new Centennial Water Treatment Plant including dissolved air flotation (DAF) clarifiers and granular activated carbon (GAC) filtration for treatment of organics, color, turbidity, and low levels of iron and manganese. The DAF system includes polyaluminum chloride for coagulation, two rapid mix chambers, and three package DAF units which each include two high rate flocculation chambers, two low-rate flocculation chambers, a saturation tank, effluent collection system, discharge weir, mechanical skimmers and beach, and associated appurtenances and controls. Three dual media filter chambers with a silica sand/course garnet base layer and GAC above are located downstream of the DAF units, prior to final chemical addition.

Additional chemical feed includes a gaseous chlorine system for disinfection, gaseous ammonia for chloramine formation, sodium fluoride for dental health, and sodium hydroxide for pH adjustment and corrosion control. The new facility also includes an advanced Supervisory Control and Data Acquisition (SCADA) system for automated control of the water treatment plant. Operators for the Town of Amherst will be able to remotely monitor and control operation of the Centennial WTP, through a recently extended town fiber optic cable network.

The design of the Centennial WTP included provisions to maintain the Amherst water distribution system, as even with the Centennial WTP offline, the clearwell of the existing facility also serves to maintain pressure in a small portion of the water distribution system between the Centennial WTP and a booster pump station. The Centennial WTP feeds the majority of the water system (excluding the portion between the WTP and the booster pump station) by gravity. Since the existing WTP including the clearwell was demolished prior to construction of the new WTP, design and construction of the new WTP included temporary water storage tanks to maintain pressure and keep all connections active in the high service area of the Amherst Public Water System.

Permitting for this project included a BRP WS 24 New Treatment Plant application with MassDEP, Site Plan Review with the Pelham Zoning Board of Appeals, and a Request for Determination of Applicability (RDA) with Pelham Conservation Commission.

The Centennial Water Treatment Plant was bid and awarded to R.H. White Construction Co. of Auburn, MA for a contract amount of $18,876,000, and the project received funding though the Drinking Water State Revolving Fund program. Construction was completed and a ribbon cutting ceremony was held in October 2025.

Sewer Feasibility Study and Sewer System Design — New Fairfield, CT

Tata & Howard completed a Sewer Feasibility Study for the Town of New Fairfield, CT to determine the feasibility of developing a sewer service area for the Town of New Fairfield town center/business district, municipal town buildings and schools, and other properties within the proposed sewer service area as well as transporting the wastewater to the City of Danbury’s Wastewater Treatment Facility. The assessment included an estimate of projected flows for all properties within the planned service area and a comparison of total estimated flows to available capacity at the Danbury Wastewater Treatment facility. Design concept plans for the planned sewer service area included determination of collection system sewers and pump station locations. Part of the study included an evaluation of potential routes for transporting flows from the Fairfield Town Center service area to the City of Danbury collection system for treatment.

Estimated project budgetary costs for the sewer service area collection system, pump stations, and transport to the City of Danbury along with a phasing and implementation plan were included in the final draft report to the Town of New Fairfield.

Throughout the course of the project, a number of meetings with the Town were held to obtain Town input and comments including one meeting at the completion of the initial assessment phase, one meeting at the completion of the concept design phase, and a series of meetings and presentations at Town Selectboard meetings to obtain public input during the roll out of the final report.

Tata & Howard provided preliminary and final design of 2.7 miles of gravity sewers, one main pump station, four remote, submersible pump stations, 2.3 miles of force mains, , and 4,000 linear feet of low pressure sewer. The project also includes identifying easements, land acquisition plans, preparation of permitting, and bidding assistance.

Preliminary design included survey, soil borings, preparation of base mapping, identification of utility requirements, a radio path survey and an opinion of probable cost.

Final design development includes final design of the main pump station, remote pump stations, gravity sewers, force main, and low-pressure sewers for connection to the City of Danbury collection system including site plans, profiles of force main and gravity sewers, pump station structures and chambers, electrical and controls, emergency generators, odor control, erosion and control plans, etc. Also includes design of the main pump station building designed to match the local aesthetic and mask it as a non-utility structure.

Construction Documents will be prepared by phasing construction under four contracts:

Year 1 – Phase 1: Main Pump Station and force main for connection to the Danbury System and Collection System for the Town Center and commercial district (Sewer Sheds 2 [commercial],
4, 5 and 8);
Year 2 – Phase 2: Collection System connecting schools, police, and fire facilities (Sewer Sheds 1 and 2 [residential]);
Year 3 – Phase 3: Additional Collection System connecting additional commercial properties, The Birches 55+ community, The Woods at Dunham Pond 55+ community, The Good Shepherd Lutheran Church, and potential future land development along Route 37 (Sewer Sheds 3, 6, and 7).

Barnstable, MA Maher WTP Upgrades

Photo courtesy of Waterline Industries Corporation

Tata & Howard provided engineering services for a completion of a pilot test proposal, pilot testing, and pilot test report to evaluate the use of granular activated carbon (GAC) to treat PFOS/PFOA, advanced oxidation to treat 1,4 dioxane, and LayneOx and greensand pressure filtration to remove iron and manganese from the source waters (Well No. 1, Well No. 2, and Well No. 3) at the existing Maher Water Treatment Plant. Pilot testing was performed, submitted, and approved by MassDEP in July 2017. The pilot test report was prepared and submitted in January 2018 to MassDEP.

Tata & Howard also provided engineering design, permitting, bidding, and construction services for the expansion of the existing Maher Water Treatment Plant. Upgrades include a new 90’ x 90’ pre-engineered metal building, GAC treatment, chemical feed upgrades, electrical upgrades at the existing plant including a new stand-by generator, and miscellaneous piping and site work. The new carbon filtration building include granular activated carbon (GAC) filters designed to remove PFAS. In addition to PFAS, the facility will include treatment processes to treat 1,4 dioxane and iron and manganese in the drinking water.

This project involved Massachusetts public construction laws and procedures.

Everett, MA Lead Service Line Replacement

Tata & Howard assisted the City of Everett, MA with their Lead Service Replacement Project from 2018-2024. Phases 1 and 2 included replacement or material confirmation of approximately 580 services between spring 2019 and fall 2022. Phase 3 of the project addressed an additional 300 services. Tata & Howard provided design, construction administration, and resident project representative services for all three phases of the project.

Design services included attending the kickoff meeting with City and reviewing existing information including tie-cards, the City’s existing GIS database that includes service material, and the City’s master list of services with service material. Each service was field verified to confirm exterior conditions. Each design phase included completion of 50% and 95% design documents, preparation of probable cost estimates, preparation of bid documents and coordination with purchasing agent, attending meetings with City, and providing recommendation to award contract to the lowest qualified bidder.

Construction Administration services for each phase included attendance at progress meetings and site visits, review of submittals, request for information, and purchasing change orders and payment applications. As-built record tie-cards were completed for each address and the master inventory of service material was updated as construction on each phase progressed.

Resident Project Representation services included full time on-site observation during construction, reviewing schedules, serving as Engineers’ liaison with Contractor, completing reports, reviewing pay apps, and issuing certification of substantial completion.

HVWP Water Distribution and Storage Improvement Project

Background

Hooksett Village Water Precinct (HVWP) Phase I Water Distribution and Storage Improvement Project is the first of three major drinking water components of the RTIA Tax Increment Financing (TIF) District economic development initiative sponsored by the Town of Hooksett. The project consisted of the construction of 1,800 linear feet of distribution system improvements in the Vista Drive area, a new 0.40 million gallon capacity glass-fused-to-steel tank, and 350 linear feet of associated transmission main from Daniel Webster Highway to Main Street.

The Precinct has been partnering with the Town, Sewer Commission, local businesses, committees, residents and area developers to encourage TIF-based infrastructure projects. TIF can be used to fund improvements that benefit the whole community by attracting new development, revitalizing blight, and/or enacting quality of life projects. This can significantly expand the tax base and provide more or easier access to services for residents with less financial impact.

Project Details

Hydraulic modeling studies completed in 2020 as part of the Precinct’s asset management program showed that distribution improvements were needed in the Vista Drive area to relieve a bottleneck that was critically restricting flow from the existing Quarry Tank and nearby wells. The Vista Drive area water main replacement/extension was listed as a Top Priority in the Precinct’s March 2021 Asset Management Plan Update. This area is the closest and primary source of water and fire protection for the TIF District, and a direct connection to the area is imperative to efficiently transmit water to the TIF District.

The Thompson Comer Tank is critical to water system hydraulics, not only for fire flow purposes but also for redundancy, emergency resiliency, and operational flexibility. It is inextricably linked to the operation of the Quarry Tank and the TIF District. Unfortunately, it had deteriorated to the point where it needed replacement. The new, slightly larger capacity replacement tank allowed the Quarry Tank to be taken offline as needed for O&M or emergencies; provide backup storage for the TIF district; allow the Quarry Tank to operate at 100% capacity; and improve overall energy efficiency by increasing off-peak operations.

Replacement of the existing Thompson Corner Tank also served as the permanent action plan to address a Significant Deficiency outlined by the New Hampshire Department of Environmental Services (NHDES) in October 2020. The deficiency identified was severe deterioration of the coating on the inside and outside of the tank. NHDES required that funding be authorized by March 2022 and a tank construction contract be awarded by October 2022.

The cost to replace the Thompson Corner tank and install the Vista Drive area water main and associated transmission main was $2,464,000 and was funded by 2021-22 NH Drinking Water & Groundwater Trust Fund (DWGTF) and NHDES American Rescue Plan Act (ARPA) Funds.

And the Winner Is…

Each fall, the Granite State Rural Water Association holds a drinking water taste test at its Annual Operator Field Day and Exhibit. In fall 2024, just after the completion of the project, HVWP had the honor of winning the contest!

Since Hooksett Village Water Precinct won the water taste test contest at Granite State Rural Water Association Operator Field Day this fall, they were able to represent New Hampshire in the National Rural Water Association’s The Great American Water Taste Test, where they won second place out of 43 systems in the National Rural Water Association’s “The Great American Water Taste Test” in Washington D. C. in February 2025. Mike Heidorn, P.G., Superintendent, represented HVWP and accepted the award.

We are very proud of the collaboration and efforts of both HVWP and the Tata & Howard team for the incredible success of our partnership.

Grafton Water District, Trinity Avenue Well Site and Pump Station

Tata & Howard provided engineering services for permitting, design, and bidding of the Trinity Avenue Pump Station at the Trinity Avenue Wellfield (new source) and provided assistance with permitting, design, and reporting to the Massachusetts Department of Environmental Protection (MassDEP) for the proposed Trinity Avenue Well site.

The property was owned by the Massachusetts Division of Fisheries and Wildlife (DFW), and the Grafton Water District swapped land with the DFW to obtain ownership and control of the Trinity Avenue site. Test wells were installed and short-term pump tests were completed on each of the wells. Based on the results of the tests, it was recommended to install a three well configuration of 18-inch x 12-inch gravel packed wells resulting in approximately 840 gallons per minute (gpm). The work under this contract included the completion of the Request for Site Exam and Pump Test Proposal for submission to MassDEP, installation and development of three (3) 18” x 12” gravel packed wells and pitless adapters, installation and development of approximately five 2-1/2” diameter observation wells, installation of two staff gages and piezometers, performing a five-day pump test, and collection and analysis of water quality.

The project also included an evaluation of alternatives for the access road including installation of a bridge or an open bottomed culvert, and Tata & Howard assisted with the preparation of permanent easements for the installation of utilities and roadway to the well site. In addition, Tata & Howard prepared and submitted an NOI to the Grafon Conservation Commission.

Design included double wythe block and interior concrete painted block with wood truss roof and asphaltic shingles. Security included chain link fence, gates, locks, intrusion alarms, and lighting. Tata & Howard also assisted 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 design also included 900 feet of new 12-inch water main for 4-log removal.

Tata & Howard also provided construction administration and resident observation services.

Rehabilitation of a 130 Year Old Tank, Newton, MA

About the System

The water distribution system in the City of Newton, MA (City) serves approximately 90,000 people and includes 319 miles of water main ranging from 2-inches up to 30-inches. There is a southern pressure zone, a northern pressure zone, and three additional high service areas. All water is supplied by Massachusetts Water Resources Authority (MWRA) and the system utilizes two tanks, the Waban Hill Reservoir and the Oak Hill Tank.

Installation of the 24-inch cast iron piping in 1890

The Waban Hill Reservoir (Reservoir) is located in the Chestnut Hill area of Newton and serves the southern pressure zone. The Commonwealth Avenue Pump Station, operated by the MWRA, serves Newton’s southern pressure zone and fills the Reservoir. The Reservoir has a capacity of approximately 10 million gallons (MG) with four chambers that were built in stages: Chamber 1 was constructed in 1891, Chamber 2 in 1901, and Chambers 3 and 4 in 1917. Each chamber is approximately 2.5 MG. At the center of the reservoir is a gate chamber building that houses the influent and effluent valves and piping to each of the chambers as well as the 90-inch diameter central core standpipe.

As shown in Figure 1, there is a 24-inch diameter common inlet/outlet line that fills the interior standpipe and then overflows equally into all four chambers. When drawing, the 24-inch diameter check valve opens and draws through the effluent lines and out the common inlet/outlet. An additional 24-inch diameter inlet/outlet pipe is located in the corner of Chamber 2 that operates Chamber 2 only if needed. During construction, Chamber 2 was used to feed the system through the secondary inlet/outlet pipe while work was completed on the effluent valves for all chambers. During construction, the effluent pipe from Chamber 2 to the core was plugged so that work could be performed on the piping and valve while keeping Chamber 2 in service.

All chambers have a drain line and valve that manifold into a 24-inch diameter drain line that runs under the existing common inlet/outlet pipe. The bottom of the interior standpipe as well as the standpipe overflow both drain into the 24-inch drain line.

Design

The original scope of the repair project included rehabilitating the 90-inch diameter standpipe, replacing four 24-inch effluent valves, and replacing the asphalt shingle roof.

Prior to construction, it was important to review the impacts of removing Chambers 1, 3, and 4 from service on the distribution system. The existing hydraulic model for the City was used to evaluate pressures and available fire flow throughout the system with just Chamber 2 online. The inlet/outlet pipe for Chamber 2 runs down Commonwealth Avenue to the Pump Station (blue line in Figure 2) while the main inlet/outlet pipe from the Central Core runs down Ward Street to the Pump Station (red line in Figure 2). Changing the location of where water enters the system from the Reservoir in turn impacted the hydraulics at certain areas of the system, specifically at higher elevations north of the Reservoir. A recently installed 12-inch diameter interconnection between the two feed lines was opened, reducing the overall headloss in the system.

The design required a contingency plan, addressing potential challenges such as losing the entire Reservoir due to a water main break on the inlet/outlet pipe to Chamber 2. Through close coordination with T&H, the City, and MWRA, an emergency response plan was created that added enhanced scenarios. T&H evaluated the model for the best location of a mobile pumping unit and location of pressure relief valves. The City installed additional hydrants so the City could use MWRA’s mobile pumping unit if needed to pump from the northern pressure zone to the southern pressure zone, which required coordinating availability of equipment with MWRA.

Following a review of the challenges, the design scope was revised. Final design and bidding on the project included standpipe rehabilitation, effluent valve and piping replacement, drain valve replacement, check valve replacement, and asphalt shingle roof replacement as well as the standpipe cover and man-way, interior lighting improvements, and instrumentation.

Construction Challenges

There were many construction challenges to overcome as part of the design. Record drawings indicated an isolation valve was located on the common inlet/outlet pipe; however, the valve was unable to be found. A new valve was installed as a change order for the project.

The construction contractor was limited to light loads due to the uncertainty of the structural integrity of the roof to support specific loads, meaning no cranes or heavy equipment could be used, and spanning a crane from the access road to the gate chamber was cost prohibitive.

The existing valves were embedded in concrete and the flanges were severely deteriorated. Because of the age of the pipe, angles and bolt patterns were not easily matched with modern piping. Therefore, stainless steel piping was used to fabricate the needed angles to connect the new valves to the common inlet/outlet pipe.

The standpipe was showing signs of severe deterioration. Under recommendations from MassTank, specialty repairs were required to prolong the life of the standpipe. Steel plates were installed at the joints within the standpipe, both interior and exterior surfaces were sand blasted, a 200 mil epoxy coating was installed on the interior surfaces, and a 10 mil coating was applied to all exterior surfaces.

Initial filling of the reservoir caused Chamber 2 to fill faster than Chambers 1, 3, and 4 which caused the Commonwealth Ave. Pump Station to shut down. Therefore, the MWRA mobile pumping unit was relocated to the Waban Hill Reservoir and water was pumped from the hatch in Chamber 2 through the hatch in Chamber 1 which was connected to Chamber 3 and 4 through the central core.

Conclusion

Construction was completed in February 2024 and the project was highly successful with minimal service interruption due to a close working partnership with Tata & Howard, the City of Newton (client), and MWRA.

PFAS Mitigation, Shrewsbury, MA

A PFAS Journey to Determine Effective Management and Treatment Options

Tata & Howard is working with the Town of Shrewsbury, MA to address perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the groundwater. The Town of Shrewsbury water system serves a population of approximately 38,300. The system consists of about 200 miles of main, nine active groundwater wells from three well sites, three pressure zones, six storage tanks, and one water treatment plant. The 7.0 million gallon per day (mgd) Home Farm Water Treatment Facility utilizes biological treatment for removal of manganese.

In 2020, Shrewsbury detected PFAS in the wells. Sampling has indicated that PFAS is present in most of the wells operated by the Town but under the maximum contaminant level (MCL) of 20 nanograms per liter (ng/L) for PFAS6 as regulated by the Massachusetts Department of Environmental Protection (MassDEP) which includes the sum of concentrations for PFOS, PFOA, PFHxS, PFNA, PFHpA, and PFDA. Raw water from one well site, the Sewell Well, has been consistently higher than 20 ng/L; but the finished water from all wells after treatment at the Home Farm Water Treatment Plant has been in compliance and consistently less than 16 ng/L. Most of the PFAS is in the form of PFOA and PFOS which are the two compounds for which the EPA has developed a proposed MCL. The PFOA indicated by the green bar in Table 1 is higher than the proposed Federal MCL of 4 ng/L.

Currently, the Town has been managing the sources to improve water quality and stay under the current MCL of 20 ng/L for PFAS6. A mass balance is utilized to estimate finished water PFAS concentrations based on updated sample results and changes in the operation of the sources. Tata & Howard created the base tool which can be used to see how changes to PFAS levels or flow rates can affect the finished water concentration.

Table 2 represents existing conditions. The numbers used for PFAS are the highest results from each individual well observed in a year of sampling data, showing the finished water level is about 16 ng/L. As long as the PFAS concentrations in the wells remain consistent, the Town will remain in compliance. If sample results change and they see an increase in PFAS concentration at Sewell, the Town will make adjustments using the mass balance to manage the sources to remain in compliance.

The Town cannot manage sources like this indefinitely. They decided to move forward with reviewing PFAS treatment options and pilot testing to determine the best course of action if/when treatment is required.

Tata & Howard and the Town considered three treatment options. The first option is anion exchange, which uses a resin with positively charged ions. These are typically single use resins and require one to three minutes of empty bed contact time. The next option is Granular Activate Carbon (GAC) which uses adsorption. This media can be made from different types of carbon sources that can be recycled through thermal reactivations and requires a ten minute empty bed contact time. There are limitations with GAC on some of the short chain PFAS. The third type is novel media, which includes other types of media that do not fall into the first two categories. The novel media piloted uses an adsorption process that is classified as a single use resin and has a two to three minute empty bed contact time.

Shrewsbury’s pilot testing utilized three anion exchange resins from two suppliers (one of which was regenerative), a coal-based GAC, and a novel media. The novel media selected works like GAC since it is not as sensitive to chlorine and chlorides, which can impact the effectiveness of anion exchange resins.

The GAC pilot test utilized two 6-inch columns in series rather than one very tall column to give more flexibility for installation and backwashing. A total of 10 gallons of media were installed with a loading rate of 7.5 gal/ft2 and an empty bed contact time of approximately ten minutes. The anion exchange and novel medias each utilized one 6-inch column with five gallons of media installed, a loading rate of 11.25 gal/ft2, and an empty bed contact time of approximately two minutes.

The water source was a tap on the effluent line from the existing filters using finished water that had been treated for manganese removal but not any of the chemical additions of KOH, phosphate, chlorine, and fluoride. There were control valves so the water only came through the unit when the treatment plant was online, which is typically more than 20 hours per day.

There was an initial baseline water quality sampling event at the start, at the end of week 20, and at the end of piloting. PFAS samples were taken day one, day seven, and then monthly for the duration of the pilot. Samples were taken from the 25% sample tap until breakthrough (50% of the raw water PFAS levels, so between 6 and 7 ppt), then at the 50% tap.

Table 3 shows the result from the different taps at the end of the pilot. The anion exchange results are from the best performing anion exchange resin. GAC was first detected in week 8 with breakthrough in the 25% tap in week 16 and the 50% tap in week 44. There was a detected amount in the final sample tap in week 64, which was the final week of the testing.

Anion exchange had the longest time to first detect but the 25% breakthrough for all anion exchange and novel media were all within a sample event or so of each other and occurred between weeks 44 and 52. The novel media had breakthrough of the 50% tap at week 60 and was detected in the 100% tap at the final week while the anion exchange was ND in the 100% tap at the end of the pilot.

Table 4 is a summary as to what the permanent filter system may look like. The filters are similar in size but the number of recommended filters differs for each resin. The overall building footprint is similar as well. The anion exchange did perform slightly better than the novel media, however, the overall PFAS removal results over the duration of the pilot was similar. Because of this, construction costs, long term media replacement costs, and operational considerations were included as part of the media selection process.

The Town has chosen to use novel media because it allows for some backwashing and chlorination, reducing the potential of biofilm buildup and potential capacity loss due to increased headloss through the media. Additionally, the novel media has a smaller footprint in comparison to GAC. The Town of Shrewsbury’s current PFAS levels do contain mostly PFOS and PFOA at concentrations higher than the proposed Federal regulations for those two compounds. Also, based on reviewing the data of the PFAS6 compounds, PFOA was the compound first detected for all media; also, the majority of the detected PFAS6 concentrations in the effluent throughout the pilot were PFOA.

One additional challenge moving forward is the design of the facility so the water goes through the manganese treatment first, the new PFAS treatment next, and finally utilizes the existing clearwell for chlorine contact, with finished water pumping into the system, all while keeping the existing treatment online during construction and start up. Tata & Howard is currently designing the facility which is being funded through the MassDEP State Revolving Fund.

Bargh Replacement Raw Water Pipeline, CT

Tata & Howard was retained by Aquarion Water Company of CT for the Bargh Replacement Raw Water Pipeline Project. The project consisted of assisting Aquarion Water Company of CT with sizing a new diversion pipeline from the Bargh Raw Water Pumping Station in to the Putnam Reservoir, both in Greenwich, CT, preparing design plans and specifications for the new 24-inch water main, assisting Aquarion with permit acquisition for the project, and performing field testing to identify the ledge profile along the main.

Construction administration and resident observation services were also performed. Stake out the pipeline, review clearing limits with Contractor, Landscape Architect, Arborist, Stamford and Greenwich, observe CCTV storm drain inspections, accompany Contractor and subs on pre-blast surveys and document, and arrange for Archeologist to delineate sensitive areas to protect.

Services: Construction