Wading River Pilot Study — Attleboro, MA

Attleboro WTP

At the Wading River Water Treatment Plant, pilot testing, conducted by Blueleaf, Inc. and consulted by Tata & Howard, Inc., was performed to evaluate the removal of natural organic material for the reduction of disinfection byproduct formation in the distribution system, the reduction of manganese concentrations, and the removal of PFAS compounds. The removal of organic carbons by magnetic ion exchange (MIEX®), the removal of manganese by GreensandPlus™ filtration, and the removal of PFAS by FLOURO-SORB®-200 media, were found to be the most effective treatment processes. 

Scaled satellite imagery of the existing Wading River Water Treatment Plant

Project Background 

The City of Attleboro, Water Department (AWD) operates the Wading River Water Treatment Plant (WTP), located in Mansfield, MA, which includes two gravel packed supply wells and submersible well pumps, each pumping from a filter sand bed. The Wading River provides additional water to the filter sand basins via a steel pile dam and intake structure, and is considered a surface water source. The wells pump to the WTP where water is chemically treated with sodium hydroxide for pH adjustment, sodium hypochlorite for disinfection, polyphosphate for corrosion control, and hydrofluorosilicic acid for dental hygiene. Treated water flows through a 630,000-gallon, baffled concrete contact tank prior to being pumped into the water distribution system. 

The Wading River source is historically a high source of organic matter, which act as disinfection byproduct (DBP) precursors in the distribution system. Despite efforts by the City to optimize existing treatment to reduce the formation of trihalomethanes (TTHMs), a class of DBPs, test results have indicated levels above the maximum contaminant level (MCL) of 80 micrograms/liter (µg/L) in some quarters, with locational running annual averages (LRAA) up to almost 85 µg/L at some sampling locations. To reduce DBP precursors and operate the WTP year-round, targeted treatment for organics removal will be required. 

Locational Running Annual Average (LRAA) of TTHMs at several locations in the Attleboro drinking water distribution system

The Massachusetts Department of Environmental Protection (MassDEP) published a new combined MCL of 20 nanograms/liter (ng/L) for six perfluoroalkyl and polyfluoroalkyl compounds (PFAS) in October 2020. Following the publication of the new standard, testing for PFAS was conducted at the Wading River supply wells and the Wading River WTP finished water in September 2020, October 2020, January 2021, and monthly from April 2021 to September 2021. Laboratory results indicated PFAS results over the limit, suggesting a need for targeted treatment. 

MassDEP guidelines require the completion of a series of permit applications and an engineering study including a pilot test proposal, pilot testing, and a pilot test report to evaluate, optimize, and summarize the treatment results. In accordance with those guidelines, three seasons of pilot testing were conducted: Season I, from March to April of 2022, Season II, from August to September of 2022, and Season III, from July to August of 2023. Per the standards to conduct a pilot study on surface water sources, the pilot test included one cold weather season and one warm weather season.

Pilot Testing 

Two systems for organics removal were tested: 1) dissolved-air flotation (DAF) followed by dual-media filtration, and 2) magnetic ion-exchange (MIEX®) followed by GreensandPlus™ filtration. The MIEX® & GreensandPlus™ filtration process train was added to the pilot test following the discovery of elevated manganese levels during Season I of testing. 

DAF clarification is a process similar to clarification by sedimentation, except that particles formed by coagulation are floated to the surface by the injection of air through a recycle stream at the bottom of the clarifier tank, instead of being allowed to settle to the bottom. The recycle stream is injected through specially designed nozzles, resulting in the formation of bubbles which adhere to formulated flocc particles and float to the surface, effectively clarifying the source water. Depending on the system utilized, typical DAF systems can operate with a surface loading rate of between 4 and 8 gallons per minute per square foot (gpm/sf). Optimal coagulation and flocculation conditions for DAF can be predicted by standard jar tests, which were conducted prior to Season I of testing. Polyaluminum chloride (PACI) was selected as the coagulant. 

Dual-media filtration is a gravity operated, rapid-flow process widely used in water treatment. It is necessary to follow the coagulation, flocculation, and clarification processes with filtration to remove excess turbidity. Dual-media filters contain a layer of anthracite on top of a layer of fine sand, which rapidly remove residual solids from the water, trapping larger particles in the anthracite and smaller particles in the fine sand. The filters can be backwashed on a schedule determined by differential pressure across the filter or at periodic time increments. 

Pilot mixers, flocculators, and dissolved-air flotation clarifier during Season III of pilot testing at the Wading River WTP

MIEX® is a specialized treatment process targeted at the removal of organic carbon, specifially dissolved organic carbon (DOC).  MIEX® resin consists of ion exchange beads that contain magnetized components to form agglomerates from negatively charged organic particles. The MIEX® system utilizes a stirred up-flow contactor, resin settler, and a regeneration/recycle loop to remove total organic compound (TOC) in an efficient manner. Batches of resin are periodically regenerated in a sodium chloride brine solution, replacing the TOC with target chloride anions and leaving a concentrated brine and organics waste stream. Freshly regenerated resin, as well as new resin to make up for carryover losses, is fed to the reactor to maintain a consistent ion exchange capacity. Depending on the system utilized, hydraulic loading rates can range from 6 to 12 gpm/sf. Residuals from MIEX® systems consist of waste from the regeneration process, and depending on the frequency of regenerations, are typically 0.02% to 0.06% of the treatment flow. 

Schematic of a typical MIEX® treatment system

GreensandPlus™, the trade name for Inversand’s oxide-coated sand product, is a manufactured filter media used for the removal of iron, manganese, hydrogen sulfide, arsenic, and radium from water supplies. The GreensandPlus™ process utilizes a layer of anthracite which acts as a physical filter for the manganese precipitated by the addition of the chlorine oxidant. Below the anthracite top layer is the oxide-coated sand media, which acts as a catalyst in the oxidation of the manganese. Manganese that is oxidized in this part of the process is then removed via adsorption or physical filtration. 

For PFAS removal, two treatments were compared: 1) granular activated carbon (GAC) and 2) an anion-exchange removal, clay bentonite media, FLOUROSORB®-200. 

GAC filtration has proven to be effective in removal of PFAS from drinking water at many locations throughout New England. GAC removes PFAS by adsorption, which is a physical process of accumulating a substance at the interface between the liquid and solid media phases. The GAC used in this pilot study was Calgon FILTRASORB 400, which is made from select grades of bituminous coal through a process known as reagglomeration to produce a highly active, durable, granular product capable of withstanding the abrasion associated with repeated backwashing, hydraulic transport, and reactivation for reuse. The Calgon FILTRASORB 400 can be recycled and reused through thermal reactivation to restore its adsorptive capacity, which eliminates the costs and long-term liability associated with the disposal of spent media. 

CETCO’s FLOURO-SORB®-200 is a proprietary, NSF-certified, bentonite-clay adsorption media that is proven to effectively treat multiple variants of PFAS. The removal mechanism is similar to anion-exchange resins. FLOURO-SORB®-200 adsorbent media binds the entire spectrum of PFAS compounds, is not negatively impacted by most other water quality parameters such as dissolved or total organic carbon and chlorine and requires short empty bed contact times of two to three minutes. 

Removal of Organic Compounds and Manganese 

As mentioned previously, manganese concentrations were found to be higher than expected during Season I of testing. The first organics removal process, DAF and dual-media filtration, was utilized to remove manganese by several oxidation strategies. The oxidation of manganese causes it to precipitate out of solution, allowing it to be removed by direct filtration through the dual-media filters. The oxidation strategies included the oxidation of manganese by potassium permanganate, sodium hypochlorite, and chlorine dioxide. While potassium permanganate was the most effective oxidation chemical for direct filtration of manganese, none of the oxidation strategies were able to consistently maintain manganese concentrations below the secondary maximum contaminant level (SMCL) of 0.05 mg/L. Additionally, DAF followed by dual-media filtration did not consistently reduce DBP precursors to maintain TTHMs below the MCL of 80 μg/L in simulated distribution system sampling. 

Box Plot of Pilot Influent Manganese Concentrations Compared to Monthly Historical Data, from Blueleaf’s “Warm-Water Season Pilot Study Report (September-August 2022).”

While GreensandPlus™ is more effective than dual-media filtration for manganese removal, providing additional oxidation of manganese with its oxide-coated media, the coagulated particles formed by DAF can be problematic for GreensandPlus™ media, “gumming up” the small particles with coagulant and reducing filter run times. Therefore, MIEX®, which does not coagulate organic particles for removal, was provided as an alternate pretreatment for the removal of organic compounds prior to manganese removal. MIEX® followed by GreensandPlus™ filtration was found to be effective for both organics and manganese removal, maintaining manganese concentrations below the SMCL, and removing DBP precursors to reduce TTHMs below 80 μg/L in simulated distribution sampling. 

Removal of PFAS 

Since many media have been shown to remove PFAS to non-detect levels, one way to measure the relative effectiveness of PFAS removal by a particular media is in terms of empty bed volumes (EBVs) between media replacement. By measuring PFAS breakthrough (defined as PFAS being higher than non-detect levels) at sampling points located 25%, 50%, 75%, and 100% through the treatment beds, EBVs for each treatment option were estimated. After 16 weeks of PFAS testing, GAC had treated almost 14,000 EBVs, and was providing 23% PFAS removal at the 25% tap, 41% removal at the 50% tap, 69% removal at the 75% tap, and 90% removal at the 100% tap. At the same time, FLOURO-SORB®-200 had treated approximately 68,600 bed volumes, and was providing 87% removal at the 25% tap, 85% removal at the 50% tap, and 100% removal at the 100% tap. The FLOURO-SORB®-200 media was determined to have a higher treatment capacity than GAC for PFAS removal.

Empty Bed Volumes Treated and PFAS6 result, by PFAS-removal process and sampling point


The DAF and dual-media filtration treatment process was utilized throughout the study to evaluate TOC removal and manganese removal by coagulation, oxidation, clarification, and filtration. A MIEX® and GreensandPlus™ treatment process was added during Seasons II and III as an alternate for TOC and manganese removal. Both processes were found to be effective in removing TOC, however, the MIEX® & GreensandPlus™ process was more effective than the DAF & dual-media filtration process in removing TOC and reducing DBP formation. Additionally, the MIEX® & GreensandPlus™ process more consistently removed manganese to concentrations under the SMCL than the DAF & dual-media filtration process. FLOURO-SORB®-200 clay bentonite anion-exchange media was found to have a higher capacity for PFAS removal than GAC. FLOURO-SORB®-200 showed significantly more bed volumes treated before PFAS breakthrough at the 25% and 50% taps than GAC showed at breakthrough of the equivalent sample tap, making it a more effective treatment media for removal of PFAS.

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.

Pilot System

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 not yet made a final decision on media type, but it appears that the novel media may be the best fit for the Town’s needs.  Specifically, the novel media 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 completing a preliminary design to better estimate costs before completing the final design, permitting, and ultimately construction.

Water Treatment Plant, Amherst, MA

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.

UMASS Amherst Hydraulic Modeling

Tata & Howard developed an extensive hydraulic model of the University of Massachusetts (UMass) Amherst campus. The model was verified under steady state and an extended period simulation (EPS) was completed. Tata & Howard conducted a hydraulic review and criticality assessment and used the results to make improvement recommendations. Tata & Howard also identified water distribution system sustainability projects for the irrigation, cooling tower makeup, and toilet flushing water.

This project included a supplemental water supply system analysis. Potential ground and surface water sources on campus, including existing and potentially new stormwater retention ponds, were evaluated for process and irrigation water. In addition, Tata & Howard created a hydraulic model of the UMass reclaimed water system.

The study also examined the effects that the proposed system improvements and interconnections would have on water quality.

Wiscasset Completes Capital Efficiency Plan™ Infrastructure Improvements

The Wiscasset Water District (WWD) completed its final phase of water main replacements for the Town of Wiscasset, ME. In 2007, Wiscasset, a rural coastal town in Maine, embarked on a long-awaited infrastructure improvement program to replace the Town’s century-old waterlines. The Wiscasset Water District, engaged Tata & Howard’s services in 2010, to prepare a Capital Efficiency Plan™ (CEP), to identify areas to the Town’s water distribution system needing rehabilitation, repair, and/or replacement.

The Capital Efficiency Plan™ report which included hydraulic modeling, system criticality, and an asset management plan, provided the Utility with a database and Geographic Information System (GIS) representation for each pipe segment within their underground piping system. The CEP report also prioritized the water distribution system piping improvements and provided estimated costs to replace or rehabilitate the water mains.

In response to the CEP™ findings, the Wiscasset Water District retained the services of Tata & Howard, to perform design, bidding, construction administration, and resident project representation services for a series of water main projects.

Wiscasset Main Street

Phased over 10 years, the plan included replacing 33,150 feet of 12-inch and 8-inch piping, installation of a water storage tank mixer, SCADA upgrades, and office landscaping improvements.

The final phase of water main replacements is scheduled to be completed during the summer of 2018 and will fulfill all the Priority I water main improvements identified in the 2010 CEP™ report. The projects were funded in part by a combination of USDA Rural Development grants (6 total) and loans (7 total), as well as coordination with the Maine Department of Transportation and Rural Development.

The final phase of water main replacements that was completed during the summer of 2018 fulfilled all the Priority I water main improvements identified in the 2010 CEP™ report. The projects were funded in part by a combination of USDA Rural Development grants (6 total) and loans (7 total), as well as coordination with the Maine Department of Transportation and Rural Development.

Extended Period Simulation and Hydraulic Study for Town of Avon, MA Water Division

Tata & Howard completed an Extended Period Simulation (EPS) hydraulic model of the water distribution system for the Town of Avon, Massachusetts. An EPS model was created to account for changes in the water distribution system over an extended period to include peak and minimum demands during both the summer and winter months. These changes included tank levels, pump controls, value operation, and demand variations.

The EPS model was used to estimate the water age in the water distribution system under winter and summer demand conditions. Water age is the time water takes to travel from a water supply source to a point within the distribution system. It is used as an indicator of water quality based on the assumption that the older the water is, the greater the likelihood that water quality has deteriorated. According to MassDEP Finished Water Storage Guidelines, a three to five-day complete water turnover is recommended in water storage tanks.

The EPS model was also utilized to evaluate the Town’s existing system operations. The model was used to determine the optimal tank operating range and the impact of the run times on the well pumps. Simulations were performed on both the Center Street and Page Street Tanks to evaluate operations under existing and projected average day demand (ADD), maximum day demand (MDD), and peak hour demands with a minimum pressure of 35 psi maintained throughout the distribution system.

In addition to analyzing the tank optimal operating levels, changes to the existing pump operations and the effect on tank levels and water age were evaluated. Two modified pump operations scenarios were evaluated. Both scenarios were run with the existing tank water level controls and allowing the Page Street Tank to drop four feet. A second modified pump operation scenario evaluated the Town’s lead/lag system. Results for the pump and tank level operations under these simulations were recorded for both summer and winter operations.

Based on the results from each operational modification, Tata & Howard made several recommendations for improvement to the water distribution system. These included allowing the water level in the Page Street and Central Street tanks to drop an additional six feet to improve water age during both the summer and winter demands.

In addition, to help improve the water age in the tanks to an optimal three to five-day complete water turnover as recommended by MassDEP Finished Water Storage Guidelines, Tata & Howard suggested installing mixing systems in each tank.

WWTP Evaluation, Manchester-By-The-Sea, MA

Tata & Howard completed a comprehensive evaluation of the Manchester-by-the-Sea wastewater treatment plant (WWTP).

The Manchester-the-Sea WWTP was originally constructed in 1998. The plant is designed to treat an average daily flow (ADF) of 1.20 mgd. The plant includes the following treatment processes: influent pumping, influent sewage grinding, manual bar rack, grit removal equipment, aeration tanks and blowers, clarifiers, chlorine disinfection, and sludge thickening.  The treated effluent is discharged into the ocean with effluent pumps through an ocean outfall pipe.

The treatment plant evaluation included a comprehensive assessment of the physical condition of the plant to provide an additional 20-year life for the facility.  The evaluation included all mechanical systems and equipment, electrical systems and controls, buildings, and structures.  The study included an evaluation of energy usage at the plant and developed recommendations to improve energy efficiency including replacement of influent and effluent pumps, and aeration blowers to better match plant flow requirements and system demands.

The final report includes an evaluation of existing conditions and proposed recommendations to improve current operations, upgrade aging equipment and facilities, improve energy efficiency,  and provide plant hardening against potential climate change and sea level rise.


Worcester, MA Hydraulic Modeling and Capital Efficiency Plan™

Tata & Howard completed a hydraulic model update and Capital Efficiency Plan™ for the City of Worcester. As part of the project, Tata & Howard updated and verified the City’s existing hydraulic model, which has over 550 miles of water main. Work included three days of fire flow tests throughout the City and allocation of demands using up-to-date billing and parcel data. Phase II of the project, 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, calculating needed storage requirements, 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.

Tata & Howard calibrated the hydraulic model under extended period simulation for an evaluation of the Super High Service Area with the Chester Street Tank off-line due to rehabilitation. The configuration of the service area included two distinct zones. The Chester Street Tank is located in one area and the Howland Hill and Apricot Tanks are located in the other area. To remove the Chester Street Tank from service, an evaluation of supply and pressures needed to be completed. The results of the analysis included running both zones off the Apricot Tank and utilizing the Chester Street Pump Station to maintain pressures within the vicinity of the Chester Street Tank.

Water Audit, Water Meter and Advanced Meter Infrastructure (AMI) Evaluation, Wayland, MA

Tata & Howard, Inc. was retained by the Town of Wayland, MA to complete a water audit of the water distribution system based on data and system information for the calendar years 2013, 2014, and 2015. The project included assessing the amount of lost water using the American Water Works Association M36 water audit methods. The report estimates the volume of lost water in terms of non-revenue water, identifies potential sources of lost water, and estimates system performance indicators including the Infrastructure Leakage Index.

The AWWA water audit results found that the Town’s non-revenue water by volume was approximately 46.4% in 2013, 20.5% in 2014, and 18.5% in 2015. The associated annual costs of water lost were approximately $425,000 in 2013, $320,000 in 2014, and $398,000 in 2015. In addition, 64% of the Town’s meters are over 15 years old.

Recommendations to reduce water loss included the following: volumetrically testing master meters at multiple flow rates and performing a field to database audit of SCADA flow reported from master meters; implementation of a customer meter testing and replacement program; and documentation of unbilled and unmetered water use with the use of meters whenever possible.

To address the aging meters, Tata & Howard completed a water meter and advanced meter infrastructure (AMI) evaluation. The project included an evaluation of water meters, automatic meter reading (AMR) systems, and advanced metering infrastructure (AMI) systems for the Town of Wayland’s water distribution system. The purpose of the evaluation was to compare different AMR/AMI technologies to assist in the selection of a new meter reading system to provide a recommendation for AMR/AMI technology to best suit the needs of the Town.

Following the meter evaluation, Tata & Howard provided assistance with a request for proposal (RFP) for new water meters and AMI system including specifications and proposal evaluation criteria. Tata & Howard is currently providing assistance during the implementation of the AMI system and the installation of the water meters and RF endpoints for the Town of Wayland.



Ozone Water Treatment Plant in Franklin, MA

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.