The wastewater treatment plant in Lyndon, Vermont was experiencing excessive odor issues. The existing odor control system relied primarily on chemical treatment, which was difficult for the operators to manage. Tata & Howard’s project design consisted of a bio-filter with root mulch to remove the odors, which are primarily ammonia, that are generated from the Auto Thermophilic Aerobic Digestion (ATAD) sludge treatment vessels. The ATAD system is a system that results in class A sludge that can be spread anywhere as a fertilizer, and it reduced the annual volume of sludge produced at this facility by 65%. The new system includes fans that pull the air off the top of the ATAD unit vessels through a cool down water wash tank, which knocks down the ammonia, and then pushes the air through PVC piping up through the root bio-filter shown in the picture. The total cost was under $300,000, for which Tata & Howard procured the Town a 100% grant.
The second part of the design project included a nitrogen reduction system for the secondary aeration process that may be necessary in the near future. The design includes a recirculation pump system from the Anoxic zone back to the Oxic zone. The Contractor was T. Buck Construction of Maine.
Tata & Howard was retained by the Southern Maine Regional Water Council (SMRWC) to complete a Regional System Study for the Portland Water District (PWD), Maine Water Company – Biddeford & Saco (MWCB&S), Kennebunk, Kennebunkport, Wells Water District (KKWWD), Sanford Water District (SWD), South Berwick Water District (SBWD), York Water District (YWD), and Kittery Water District (KWD).
The purpose of the study was to provide a detailed update to their 2008 Regional Water System Master Plan Study, which studied possible interconnections between the water systems within the SMRWC. A combined water distribution system regional hydraulic model was developed using the hydraulic models of each individual water system. The regional hydraulic model was used to evaluate the hydraulic feasibility and impacts of the proposed interconnections as well as the potential of transferring water from northern systems to southern systems through a completely connected and open system. The PWD and MWCB&S have large water sources and are interested in exploring the option of providing water to southern systems. The study evaluated the needed infrastructure improvements, each system’s available water supply, and demands through the potential and existing interconnections.
The study also examined the effects that the proposed system improvements and interconnections would have on water quality. Not all water systems treat water in the same way; therefore, finished water is unique to the chemicals and treatment techniques used by each system. Specifically, pertinent available data was collected and chemicals used for coagulation, sequestering, primary disinfection, secondary disinfection, corrosion control, pH adjustment, and dental health were reviewed. Raw and finished water parameters such as turbidity, alkalinity, temperature, pH, and total hardness were also collected. Of the seven participating water systems in the study, three disinfect with chloramines and four disinfect with only chlorine solution. Operating the systems together as a permanent solution to water supply concerns would require modifications to the treatment processes in some if not all of the systems. Ideally, each water system involved in water sharing would need to agree to a treatment method to give each system acceptable water quality and eliminate concerns with blending systems.
The identified improvements were based on hydraulic feasibility. Infrastructure recommendations at the interconnection locations include construction of new water mains, pressure reducing valves, and booster pumping stations.
Through a grant from the Pioneer Valley Planning Commission, Tata & Howard was retained by the City of Northampton Department of Public Works (Northampton) and the City of Easthampton Water Works (Easthampton) to complete a Regional Intermunicipal Interconnection Evaluation for the Easthampton, Hatfield, Northampton, Southampton, and Williamsburg water systems. The purpose of the study is to evaluate potential water distribution system intermunicipal connections and emergency water supply. A combined water distribution system regional hydraulic model was developed and used to evaluate the hydraulic feasibility and impacts of the proposed interconnections. The study evaluated the needed infrastructure improvements, system available supply and demands, and available supply through the potential interconnections.
Potential interconnection locations between Northampton and Easthampton were considered at four locations, between Northampton and Hatfield, between Northampton and Williamsburg, and between Easthampton and Southampton. Infrastructure recommendations at the locations include construction of new water mains, meter pits, flow meters, pressure reducing valves (PRV) and portable pumping systems. The Massachusetts Department of Environmental Protection (MassDEP) Water Management Act (WMA) permitted and registered pumping volumes for each system’s sources was evaluated for potential supply to other communities. Northampton and Easthampton have surplus supply, while Hatfield, Williamsburg, and Southampton are approaching their WMA permit or registration allowable withdrawal volumes.
The study determined the following:
Three of the four potential interconnection locations between Northampton and Easthampton could be utilized in an emergency by isolating portions of Northampton’s system. An interconnection that could serve all of Northampton would require a pumping system.
A pressure reducing valve would be required to supply Hatfield from Northampton and a pumping system would be required to supply Northampton from Hatfield.
Due to the location of the Williamsburg interconnection along Northampton’s transmission main route, and the limited amount of water available from Williamsburg, an interconnection from Williamsburg to Northampton is not feasible.
There is an existing hydrant to hydrant interconnection between Easthampton and Southampton that has been utilized to supply water to Southampton during periods of high summer demands. To supply the entire Southampton system, a pumping system would be required, and a PRV would be required to maintain adequate pressures if Southampton were to supply Easthampton.
Tata & Howard provided general engineering services to Bellemont Water System associated with responding to Arizona Department of Environmental Quality (ADEQ) violations and preparing an Application for the Groundwater Compliance 4-Log Removal of Viruses. Randall Pellatz, P.E., from Tata & Howard’s Flagstaff office, served as Project Manager.
Located west of Flagstaff in the unincorporated community of Bellemont, the water system served approximately 100 customers — the majority of whom receive water hauled by truck to cisterns at their homes — as well as a few businesses, including a strip mall. The system also provides some fire protection. After the system repeatedly tested positive for E. coli bacteria and total coliform bacteria, a boil water notice was issued in August of 2012. In June of 2013, ADEQ issued a compliance order that required the Bellemont Water System to notify all customers of the boil water advisory and to install a treatment system that satisfactorily removes bacteria and viruses from the water. The source of the contamination was unknown.
Tata & Howard’s scope of services included providing a response to ADEQ’s compliance order and developing a preliminary plan of action for maintaining 4-Log Removal of Viruses for the Bellemont Water System. In addition, a preliminary schematic plan for a chlorination system was developed to provide a residual chlorine concentration throughout the Bellemont Water System. Tata & Howard also provided design services for the proposed disinfection system and completed an assessment of the existing conditions of the Bellemont Water System, including recommendations, in a letter report.
The system’s operator, Jeremy McCabe, installed the disinfection system, and in June of 2016, the Bellemont Water System underwent their final field inspection from ADEQ for chlorine residual and 4-log removal. They passed easily, and ADEQ was pleased to remove the boil water requirement. Mr. McCabe commented on how well the system now operates, and the system’s customers have expressed how happy they are to once again have safe, clean water.
Owner: Aquarion Water Company, Shelton, Connecticut
Tata & Howard provided professional engineering services for surveys and mapping; subsurface explorations; preliminary and final design; bidding; and construction phase services, including resident project representation, for the partial replacement of Laurel Reservoir Raw Water Transmission Main located on Lakeside Drive in Stamford, CT. The main was replaced after a history of multiple pipe failures.
This project included replacing approximately 3,670 feet of an existing 13,540 feet of 42-inch diameter prestressed concrete cylinder pipe (PCCP) used to transfer raw water by gravity from Laurel Reservoir to the Stamford Water Treatment Plant (WTP). The pipe was replaced with 48-inch Class 52 ductile iron pipe. Three existing 8-inch blowoffs and two existing 4-inch diameter automatic air release valves in this section of main were replaced and upsized with new 12-inch diameter blowoffs and 12-inch diameter valves. The main was encased in concrete at three culvert crossings. Additionally, two 24-inch diameter access openings were installed in the existing 42-inch diameter main that was not being replaced to allow for inspections while the pipe was drained and out of service. The project also included replacement of four existing automatic air release valves on the existing 42-inch diameter PCCP that was to remain in service.
Jacking a 48-inch steel casing under I-84 in Danbury, CT
The Oakland Avenue sanitary sewer project consisted of jacking a 48-inch steel casing pipe through the Interstate-84 embankment in Danbury, CT and installing a new 24-inch sanitary sewer to replace the existing 16-inch sewer that is undersized. The project alleviated the restriction that is causing sewer overflows. Services included surveys and mapping, review of easements, review and updating of original design, preparation of plans and specifications, bidding, construction administration, and resident observation. The new sewer line installation will complete an interceptor project that was constructed in 1994.
Tata & Howard provided engineering services for a comprehensive water distribution system evaluation and study. The work included development of a hydraulic model using WaterCad software. The plan included fire flow tests, review of the water supply agreement with the City of Worcester, preparation of projected water demands based on historical use and population trends, and evaluation of storage. The plan also included an evaluation of potential water supply sources within Town boundaries.
This project included an evaluation of the system prior to design of the tank to determine the best solution. Work included calibrating the model under extended period simulation (EPS). The hydraulic model was used to determine the best hydraulic gradeline elevation of the system to reduce the storage surplus. Additionally, the model was used to track the chlorine residual from the Worcester Pump Station to the extremities. Jar testing was completed to determine the chlorine demand in the water supply while water quality testing results assisted with determining the chlorine demand in the piping system. The model was used to simulate the chlorine degradation. Improvements were input into the hydraulic model and the effects on the chlorine residual in the extremities reported. Improvements such as an elevated tank at Maple Street with a total usable volume, reduction in hydraulic gradeline elevation, and cleaning and lining water mains were evaluated. The analysis determined that a new tank at Maple Street is necessary based on water quality and cost.
Tata & Howard provided assistance with the preparation and submittal of a Project Evaluation Form to the Massachusetts Department of Environmental Protection for the construction of a new elevated tank with a capacity of 0.2 million gallons. The new tank reduced the water age in the system by replacing the deteriorating ground level tank. Tata & Howard provided construction administration and resident observation services for the new tank, which was completed in 2016.
Whitepaper:
ABSTRACT: In 2012, the Town of Paxton, MA was experiencing significantly reduced chlorine residuals in the extremities of the system along with an aging water tank that required extensive rehabilitation. As a result, the Paxton Department of Public Works (DPW) determined the need to create an extended period simulation (EPS) hydraulic model to evaluate the water age and water quality in the distribution system. The study examined the residual chlorine concentrations and water age throughout the distribution system and presented various options to help mitigate these issues, including replacing the aging tank and adding a chlorine booster pump station at the existing site. Construction of the new tank and pump station was completed in the summer of 2016. Read the complete whitepaper by clicking below:
To download “Town of Paxton, Massachusetts Distribution System Evaluation and Improvements” whitepaper instantly, simply fill out the form below:
The Whitin Wellfield Water Treatment Facility design consisted of a pressure filtration vessel housed within a new pre-fabricated metal building, and upgrades to the chemical feed system housed within an existing building on site. The project also included associated electrical and instrumentation, as well as site stormwater management.
The design called for replacement of the existing paved driveway, but since no new impervious pavement was added, the only stormwater runoff that required treatment was the rooftop runoff from the new building. MassDEP guidelines require treatment of runoff from metal roofed buildings within the Zone II radius of a wellfield.
The necessary treatment was achieved by discharging the roof runoff into a grass-lined channel. The grass-lined channel provided pre-treatment for a bioretention area, which consisted of a shallow excavation in which specially selected metal-resistant grasses and shrubs were planted within a specific soil to provide treatment. This treatment train provided the necessary total suspended solids removal but did not receive credit for infiltration, which was required by MassDEP. The biofiltration area was designed to collect, store, and infiltrate a 100-year storm event, so although the BMP train did not receive credit by MassDEP standards, the local Conservation Commission agreed that runoff would be infiltrated and therefore approved the design.
Tata & Howard completed a Water/Wastewater and Related Departmental Organizational Plan for the City of Westfield. Prior to the start of work, the organization included a Water Resources Superintendent, a Wastewater Superintendent, and other department heads to provide water, wastewater, stormwater, and highway services. The chief project goal was to seek alignment of people, business processes, and technology.
Tata & Howard reviewed relevant documents, facilitated individual interviews with knowledgeable managers and staff, and conducted on-site workshops as appropriate to evaluate the City’s current organization against desired business goals and industry best practices. We recommended a revised organization to the City which is in the process of being approved through the City Council. Upon acceptance of the new organization, a detailed report will be submitted.
Tata & Howard provided evaluation, design, construction administration, and resident observation services to the South Central Connecticut Regional Water Authority (SCCRWA) for the replacement of the Whitney-Wintergreen water storage tank. The project included an analysis of SCCRWA’s Whitney-Wintergreen service area to determine the appropriate volume of storage needed to serve its customers, and a 1 million gallon concrete tank was constructed to replace the existing 1.5 million gallon steel tank at the same site. The project also included demolition of the existing tank as well as stormwater management at the site. The project was completed in September of 2015.
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