Tata & Howard contracted with the Town of Amherst for design, permitting, and bidding of the 1.5 million gallon per day (MGD) Centennial Water Treatment Plant, 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 polyaluminaum 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 4-log inactivation of viruses, 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 will be demolished prior to construction of the new WTP, design and construction of the new WTP will include a temporary water storage tank 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 recently bid and awarded to R.H. White Construction Co. of Auburn, MA for a contract amount of $18,876,000. This project received funding though the Drinking Water State Revolving Fund program, and construction is expected to be completed by the summer of 2025.
Biological manganese filters (above) come after the packed tower aerator for efficient removal of manganese.
The project included a culvert reconstruction to replace a damaged pipe. Culverts are trench-like constructs designed to allow free-flowing water beneath a road or railway, whether stormwater or a stream. Pictured is the finished culvert over Godfrey Brook, a tributary to the Charles River.
T&H team members Matt O’Dowd, Juliette Burcham, Mitch Garon, and Barry Pociask review the electrical connection for the disconnect of the submersible well pump for well 1A. The Godfrey Brook Wellfield features seven total gravel packed wells: five rehabilitated and two newly installed.
The newly installed chemical feed system includes skid-mounted chemical metering pumps used for potassium hydroxide; here, chemical addition occurs for pH adjustment, along with the addition of sodium hypochlorite for disinfection and zinc orthophosphate for corrosion control prior to entering the water distribution system.
The Towns of Canaan, Vermont and Stewartstown, New Hampshire operate a shared wastewater treatment facility, which required significant upgrades. The existing facilities were 40 years old and although a few upgrades were performed in the 90s, the facilities were not performing well, did not meet Life Safety codes, and required significant maintenance. The upgrade met all of the goals of the Client by providing for simple operation and maintenance requirements, meeting the Life Safety codes, eliminating confined spaces, lowering of electrical power costs, and meeting discharge parameters through production of high quality effluent. The solutions developed for the upgrade to this facility were also economical.
Tata & Howard provided design and construction services for a new water treatment facility that houses a 1.2 mgd ultrafiltration system and completed a pilot test that consisted of an evaluation of two separate ultrafiltration technologies. Franklin Wells No. 1 and 2, located off Hayward Street in Franklin, Massachusetts were installed in the 1940’s with a combined safe yield of 1.2 million gallons per day. Due to high concentrations of iron and manganese in the groundwater, the wells were only used to meet peak water demands during the summer months. The construction of the water treatment facility recaptures the yield from these two sources. The water treatment facility consists of a main building which houses static mixers, ozone feed equipment, chemical feed equipment, prefilters, membrane filtration equipment, instrumentation and controls. Treatment consists of ozone oxidation followed by membrane ultrafiltration. The project was funded in part by the Massachusetts Water Pollution Abatement Trust through a low interest state revolving fund loan.
The overall treatment scheme is as follows: ozone injection, oxidation of iron and manganese in an ozone contact tank, prefiltration, treatment through two ultrafiltration membrane skids, chlorination prior to a clearwell, and fluoride addition prior to discharge into the distribution system. The plant is designed to recycle backwash water and membrane recirculation water to the head of the plant utilizing two decant tanks. Ozone is produced on site utilizing compressed air, while a LOX tank is available to allow for the production of additional ozone if required in the future.
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.
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.
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.