Water Archives - Page 8 of 10

Water Mains, DWSRF, Uxbridge, MA

Tata & Howard is assisting the Town of Uxbridge with the design of 18,200 linear feet of 12-inch diameter water main on Route 122 from the Blackstone River to the Northbridge Town boundary. Work includes the preparation of design plans and specifications, permitting with the local Conservation Commission, MESA, and MassDOT, and the preparation of the Drinking Water State Revolving Fund (DWSRF) application, plans, and specifications checklist for the Route 122 water main design.

In addition, Tata & Howard provided design, permitting, and construction administration services for approximately 4,750 and 1,560 linear feet of 20-inch and 12-inch diameter water main, respectively, on Quaker Highway.

Water System Operations Plan, Falmouth, MA

Tata & Howard, Inc. prepared a Water System Operations Plan for the Falmouth water system. As part of the Settlement Agreement between the Town of Falmouth and the Commonwealth of Massachusetts, the Town agreed to complete a Water System Operations Plan. The purpose of the plan was to evaluate seasonal demands, current source and storage tank operations and identify system and operational changes necessary to address distribution areas with low chlorine residuals.

The Town of Falmouth’s water distribution system consists of approximately 400 miles of water mains of various materials ranging in size from six to 24 inches in diameter. The Town has five active water supply sources including both groundwater and a currently unfiltered surface supply. Each source is treated with sodium hypochlorite for disinfection with the exception of Long Pond, which includes disinfection with chlorine gas. Falmouth’s water distribution system includes four water storage tanks and a Supervisory Control and Data Acquisition (SCADA) system to run and monitor operations.

The Falmouth Water Department faced a number of challenges, including the following:

Maintaining regulatory compliance
Meeting water demands
Peak summer demands could only be met with Long Pond surface supply
Long Pond is an unfiltered surface water supply
Constant struggle to maintain treatment compliance and water quality
Seasonal impacts from turnover or algae growth
Lack of treatment to address taste, odor, and color can require severe curtailment in use of the supply
Excessive source chlorine residuals needed to maintain distribution system residual chlorine concentrations, combined with source water organics results in elevated disinfection by-products (DBP – Total Trihalomethanes and Haloacetic Acids) which are regulated compounds

The study reviewed the challenges above and recommended changes to systems operations procedures to improve water quality. We used a hydraulic model to determine water age and look at its impacts on water quality. The plan was submitted and approved by Mass DEP.

Additionally, Tata & Howard completed the design of a 3.6 mgd 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 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.

DAF Water Treatment Facility Construction and Startup

Tata & Howard provided construction administration, resident observation, and start-up services to the Milford Water Company for the construction of the Dilla Street DAF Water Treatment Facility. The 5.2 mgd facility treats water from a combination of lake, river, and wells, utilizing dissolved air flotation (DAF) clarifiers and granular activated carbon (GAC) filters. The facility replaced the existing slow-sand and diatomaceous earth (DE) treatment previously utilized to treat the existing surface and groundwater sources, respectively. The facility was required to address and satisfy an Administrative Consent Order (ACO) issued by MassDEP.

Tata & Howard also completed design and oversight of a redundant cast-in-place chlorine contact tank, and has been contracted to provide engineering services for project review and construction oversight for the installation of raw water screens on intakes of both the lake and river sources. These improvements were mandated by MassDEP as part of the approval of the Dilla Street facility design.

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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Project Category: Water