Small-to-Midsize Municipalities Archives - Page 8 of 11

Water Treatment Facilities, Canton, MA

The Town of Canton had primarily been relying on water from the Massachusetts Water Resources Authority (MWRA) for a majority of its water supply needs since 2003 due to the poor water quality of their well supplies. In order to reduce the amount of water purchased from MWRA, the Town began investigations of water treatment options for iron and manganese removal. In 2005, Tata & Howard conducted a pilot test using water from Well No. 9 since it represented what was considered the worst water quality particularly with regard to iron concentration. The pilot testing indicated that oxidation with potassium permanganate followed by membrane ultrafiltration would be successful in reducing the elevated levels of iron and manganese to below the Secondary Maximum Contaminant Levels of 0.3 mg/l and 0.05 mg/l, respectively. Based on the results of preliminary pilot testing, a system from Koch Membrane Systems, Inc. (Koch) of Wilmington, Massachusetts was used.

In addition to the pilot study, Tata & Howard performed a feasibility study to determine the best location for a treatment facility for all of their well supplies. The recommended location for a single facility was a Town-owned property between Charles Drive and Pecunit Street adjacent to the Well Nos. 11 and 12 site, requiring the construction of approximately 14,500-feet of transmission main. Due to the significant cost of the transmission mains, the disruption of traffic throughout the Town from road excavation for construction of those mains, and the unknown cost of the required permitting activities for the transmission mains, the Town decided on the construction of two treatment facilities.

Tata & Howard provided engineering design and construction administration services for two water treatment facilities. Piloting for the projects was completed at two well sites. The Neponset Street Water Treatment Facility (WTF) has a design capacity of 2.53 mgd. The facility use ultrafiltration with chlorine dioxide for treatment. The Pecunit Street WTF has a design capacity of 0.95 mgd and uses LayneOx with chlorination for treatment. The two treatment facilities allowed the Town to reduce the volume of water purchased by the MWRA.

Water Treatment Facility, Falmouth, MA

Tata & Howard completed the design of a 3.6 mgd water treatment facility which utilizes air stripping and pressure filtration technology for the removal of iron, manganese and volatile organic compounds (VOCs). The facility includes an air stripping tower, three greensand filtration units, horizontal carbon contactors, chemical storage and feed facilities, gravel pack supply well, finished water storage, and backwash holding tanks.

Water Treatment Plant Dissolved Air Flotation (DAF) Pilot Study, Norwich, CT

The NPU contracted with Tata & Howard for the design and construction of renovations at the Stony Brook Water Treatment Plant. The NPU was challenged by an apparent and relatively abrupt change in raw water quality as a result of a green algae bloom consisting primarily of chlorophyta beginning in the summer of 2010. The original project requested the replacement of the media in the filter clarifier units with buoyant media. T&H proposed an alternative approach to not replace the media but rather add a new unit operation to the plant. Our belief was that simply changing the media at this plant would not have appreciably changed the treated water quality. T&H recently completed piloting a Dissolved Air Flotation (DAF) system at the plant to improve treated water quality.

Tata & Howard prepared a pilot test plan for DAF Clarifier piloting at the Stony Brook Water Treatment Plant site and conducted one summer season of DAF clarifier and filtration piloting. A pilot study report was prepared, including water quality data, evaluation of the treatment system, chemical dosages, flow rates, conclusions, recommended process, and design criteria. As a part of the pilot study, bench scale testing was performed to examine the performance of coagulants and polymers at various dosages and mix rates for the best removal of disinfection by-product (DBP) precursors. The bench scale testing was performed simultaneously with the pilot test and results were incorporated into the pilot test program.

In addition, T&H prepared design drawings and specifications for a 4.0 mgd capacity DAF clarifier system to be added to the plant to remove algae and to remove a greater level of disinfection by-product precursors. Additionally, we assisted with bidding of the project and provided construction administration and resident observation services.

Capital Efficiency Plan™ including Water System Master Plan, Northampton, MA

Tata & Howard has completed a Water System Capital Efficiency Plan™ for the City of Northampton. The plan includes a comprehensive water system master plan that evaluates the hydraulics of the system as well as critical components and asset management considerations. The hydraulic analysis included completion of fire flow testing and c-factor tests. Tata & Howard developed a hydraulic model from the City’s extensive ArcGIS database and the flow test results were used in verification. Tata & Howard reviewed recommended static pressures and Insurance Service Office recommended fire flows as well as estimated needed residential and commercial fire flows throughout the system.

The Northampton water system has wide range of ground elevations, resulting in extreme high and low static pressures in some areas. To maintain recommended system pressures, a new service zone was recommended to divide the distribution system. The recommendations included a new water storage tank, pressure reducing valves and transmission main improvements. Tata & Howard also developed additional recommended water main improvements to meet fire flow needs.

The asset management portion of the project included a detailed analysis of each segment of pipe in the water system based on age, diameter, material, pressure, soil conditions, break history, and potential water hammer. Each segment of pipe was given a numeric rating based on weighted asset criteria developed in cooperation with the City. This information was used with the hydraulic evaluation and critical component assessment to determine the prioritized improvements for the system.

Tata & Howard is also assisting the City with testing of pipes throughout the system. The work includes visual evaluation of samples and pipe strength testing. An analysis of the estimated service factor of each pipe segment will be provided to the City and used to supplement the information obtained during our asset management analysis.

Distribution System Water Quality Study, Norwich, CT

Tata & Howard, Inc. was retained by the Norwich Public Utilities (NPU) in Norwich, Connecticut to perform a distribution system water quality study to evaluate the water age, water quality, and hydraulic gradient in the Taftville/Occum Service Area. The Taftville/Occum Service Area has high water age, due primarily to the large volume of the Occum Tank. In addition, high levels of total trihalomethanes (TTHM) are observed throughout the Taftville/Occum Service Area.

This study examined the TTHM concentrations and high water age in the Taftville/Occum Service Area and presents various options to help mitigate these issues.

During the course of this study the following tasks were completed:

Updated the existing WaterGEMS hydraulic model using recent system data
Collected water distribution system data on current operating conditions,
historical and current disinfection by-product samples, water age, pressures, flows, and tank levels and supply and demand data for the entire NPU system
Conducted a gradient evaluation of the affected service area and investigated potential alternatives to improve the current conditions, including making short and long term capital improvements to provide improved tank level fluctuation and improved customer pressure ranges
Performed water age modeling of the existing service area and for potential
alternatives that improve the current conditions and graphed the results
Provided information and costs for alternatives to the tank passive mixing system
Provided recommendations for improving the service area gradient(s), water age, and water quality
To evaluate the Taftville/Occum Service Area, the entire NPU distribution system needed to be examined to determine the quality of the water as it enters the service area.

The key finding from this study related to the TTHM levels in the Taftville/Occum Service Area was that the formation potential in the effluent water from both of NPU’s surface water treatment plants was high enough for the TTHMs to exceed 80 µg/L at the entry point to the service area.

Based on this study, NPU has decided to add dissolved air flotation (DAF) to its Stony Brook water treatment plant. Tata & Howard designed the DAF system and other related improvements.

District Water Treatment Facility, Transmission Mains, and Metering Station, Mattapoisett, MA

The MRVWD water treatment facility project was designed to treat water from eight wells belonging to the Towns of Fairhaven, Marion and Mattapoisett. The MRVWD facilities also include approximately 5 miles of raw water transmission mains between the wells and the water treatment facility, finished water transmission mains from the water treatment facility to the existing town transmission mains, six new 100 HP high lift pumps and control/metering stations. The existing pump stations were upgraded to pump water to the water treatment facility but operation of the pump stations will remain the responsibility of the individual towns.

The total cost of all project components was approximately $16.5 million, which was partially funded with a low interest SRF loan. By constructing a regional facility, the towns were able to save over $4.9 million in design and construction costs in comparison to individual treatment facilities.

On-Call Water Engineering Services, Franklin, NH

Tata & Howard has been assisting the City of Franklin, New Hampshire with general water engineering services since 2009. The Tata & Howard team has managed several phases of work, including the design and construction of the water treatment plant and distribution system improvements.

The first phase was the design and construction of 2,500 linear feet of water main on Hill Road to connect a new water treatment plant to the City’s distribution system. This project also involved use of four bioretention systems to treat and manage stormwater from the roadway, and was constructed in 2010.

The second phase of our work with the City included the design and construction of two parallel 2,500 LF sections of 12-inch diameter HDPE crossings beneath the Pemigewasset River using horizontal directional drilling to transport water from the City’s Franklin Falls Well to the water treatment plant site.

Tata & Howard managed the survey and geophysical studies and prepared a Preliminary Design Report and Environmental Review documents for several phases of work. The City’s wells are surrounded by lands controlled by the US Army Corps of Engineers, which required that we complete an extensive permitting process to secure permissions for the final design of the project.

Tata & Howard completed design, construction, permitting, and funding applications for a 1,000 gallons per minute groundwater treatment plant to remove iron and manganese from three of the City’s wells. The plant has four pressure filters containing Greensand Plus media and using sodium hypochlorite for oxidation and sodium carbonate (soda ash) for pH adjustment. This plant went online July 9, 2012.

Tata & Howard provided design services for the construction of a new prestressed concrete tank at the site of an existing tank. The existing tank was in poor condition and due to the site characteristics, it was determined that construction of the new tank on the existing foundation of the old tank would be the best option. A second tank on the site was demolished in 2013 and a new prestressed concrete tank will be constructed in its place.

Tata & Howard also conducted a full water system analysis for the City of Franklin, New Hampshire by utilizing our proprietary Capital Efficiency Plan™ methodology. Our CEP involved creating a model of all water infrastructure in the City including sources, pump stations, treatment facilities, storage facilities, transmission, and distribution lines. Using our GIS modeling software, the system was calibrated based on fire flows in an attempt to accurately replicate the existing system. We then pinpointed deficiencies within the system based on a custom rating scale given to multiple criteria such as age, break history, material type, criticality and size. Recommendations were made for improvements in order of need. The study renewed both above ground and below ground assets. Funding for this study was in part from an Asset Management Planning Grant from NHDES.

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Replacement Wells, Ayer, MA

Grove Pond Replacement Wells No. 1 and No. 2
Grove Pond Well No. 3
Spectacle Pond Replacement Wells No. 1 and No. 2
Department of Public Works, Ayer, Massachusetts

Tata & Howard has been providing engineering services to the Town of Ayer for their water supply sources. Our work has included permitting and design of replacement wells at the Grove Pond Well site, development of a new source at the Grove Pond site, and replacement wells at the Spectacle Pond Well site. Due to elevated concentrations of iron and manganese at both sites, the intent of the replacement well program was to regain lost capacity of the existing sources and reduce the frequency of rehabilitation of the existing sources. All the replacement wells with the exception the replacement wells at Spectacle Pond Well No. 2 were single gravel packed replacement wells. Due to Zone I ownership issues, Spectacle Pond Well No. 2 is being replaced with three 16” x 10” gravel packed wells in a wellfield configuration. Each replacement well project initiated with test well exploratory programs to identify the potential location, yield, and water quality. With the Spectacle Pond Well No. 2 Replacement Well, we met with MassDEP to discuss the concept, duration of the pump test, and monitoring requirements prior to submittal of the pump test proposal.

Our scope of services for the replacement well and new source projects included test well exploration programs, permitting with the Ayer Conservation Commission and Nature Heritage and Endangered Species Program, MassDevelopment for the Grove Pond Wells, Water Management Act (WMA) program for the third well at Grove Pond, conductance of pump tests, preparation of pump tests reports in accordance with MassDEP requirements, design of the necessary infrastructure and production wells to connect the existing wells to the influent main into the existing respective water treatment facilities, construction and post construction services.

Satellite and Replacement Wells, Shrewsbury, MA

Tata & Howard has been providing engineering services to the Town of Shrewsbury for their water supply sources. Our work has included permitting and design of satellite and replacement wells at the Home Farm Wells No. 6-2 and No. 6-4 and the Lambert Replacement Well No. 3-1. The intent of the project was to regain lost capacity of the existing sources.

The approved withdrawal rate from Lambert Well No. 3-1 is 0.75 mgd. The permitted withdrawal cannot be attained because the existing well screen has failed. Installation of an 18” x 12” gravel packed replacement well removed the threat of problems associated with the collapsed screen.

The approved withdrawal rate from Home Farm Well No. 6-2 is 3.02 mgd. Despite rehabilitation efforts, the capacity of Well No. 6-2 has significantly decreased. An 18” x 12” gravel packed replacement well was constructed and permitted to replace a portion of the flows from the existing Well No. 6-2 to meet the demands of the system and to better manage their sources. By dividing the approved withdrawal rate of Well No. 6-2 between the existing well and the replacement well, the water velocities will decrease and the efficiency of the wells will increase.

Both replacement well projects required permitting with the Shrewsbury Conservation Commission and MassDEP, preparation of bid documents for the installation of gravel packed production wells and pump test, 24 hour pump test with water quality analysis, preparation of pump test reports, design of necessary infrastructure including submersible pumps, variable frequency drives (VFDs) and piping to connect to the existing water treatment facility.

Standpipe Rehabilitation, Oak Bluffs, MA

Oak Bluffs Water District, Oak Bluffs, MA

Tata & Howard has provided engineering consulting services for the design, Contract Document preparation, and bid assistance to the Oak Bluffs Water District for the interior and exterior standpipe rehabilitation of the Alpine Avenue Standpipe. We are currently providing construction administration services for the rehabilitation project.

The standpipe has a capacity of 2.0 million gallon and is a welded steel standpipe constructed in 1983. Additional work included removal of a telemetry building attached to the standpipe and design of a precast concrete building to house a tank level transmitter and communications equipment. The standpipe houses cellular carrier equipment and other communications equipment that was considered throughout the design. The Oak Bluffs water system maintains only one water storage tank. To provide adequate storage throughout the completion of the rehabilitation project an interconnection with Edgartown was opened.

Tata & Howard, Inc. coordinated the interconnection opening with the Oak Bluffs Water District, the Edgartown Water Department, and the Massachusetts Department of Environmental Protection. Oak Bluffs is a community that experiences significant demand increases throughout the summer months, therefore there was a very short window for project completion because the limiting weather conditions and increased summer demands. The project is currently on schedule and within budget.

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