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.
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:
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.
Tata & Howard designed and constructed the improvements to eliminate low and inadequate system pressures, construct a new source, pilot test filtration for manganese removal, design and construct required distribution system piping to connect the plant and storage tank with the system, design a new concrete storage tank, booster pump stations, and the filtration facility for manganese removal. The project was very successful and remains in great condition today.
The exposed water main ran under the bridge on Mechanic Street
Tata & Howard provided engineering consulting services to the Town of Monson, Massachusetts for the relocation of the 8-inch diameter water main on Mechanic Street.
The main was originally constructed in 1897 under the streambed; however, after 117 years in this location, the decrease in surface water elevation had exposed the water main. The water level averaged about one inch below the top of pipe, exposing the top portion of the entire section of main that crossed the brook, approximately 15 linear feet of main. Exposure of the water main made it susceptible to freezing during the winter months, which could have resulted in a break and subsequent lost water or contamination from the brook to the Town’s entire water system, potentially resulting in significant costs to residents and to repair, clean, and disinfect the system. The main provides potable water to approximately fifty residents. There were only two gate valves located at the ends of Mechanic Street. As a result, if the main were to fail at the bridge, the entire street would have to be shut down in order to repair the damage, disrupting water service for the 50 serviced residents.
The Mechanic Street Bridge has a history of failure. As a result of a major flood event in 1955, the bridge failed and was completely replaced in 1956. The bridge ran directly over the water main, which posed an additional threat to the main should the failure reoccur. Although the main was unaffected during the previous failure, its weakened condition made it more susceptible to failure in a similar event.
Tata & Howard provided funding assistance and the project qualified for and received a FEMA Hazard Mitigation Grant for 75% of the cost of the project. The work included the preparation of design plans and specifications for the relocation of the 8-inch water main to a self-supporting beam structure attached to the bridge abutments on Mechanic Street. The project also included bidding, permitting, construction administration, and resident observation.
Tata & Howard assisted Maine Water Company with mechanical, structural, and architectural design of a new high service zone booster pump station on Barra Road within the Biddeford-Saco water distribution system. The new pump station replaced the existing Alfred Road station, providing pumping capacity to meet current demands in a majority of the City of Biddeford as well as room for future expansion. Funding for the project was provided in part by the Maine Drinking Water Program State Revolving Fund (DWSRF).
Mechanical design for the project consisted of sizing and selection of three (3) centrifugal booster pumps, associated piping, and appurtenances. The pumps were sized with input from a hydraulic model of the system developed by Tata & Howard, and they were selected to maximize the available flow from a 16” cast iron pipe line that crosses the Maine Turnpike from the water system’s major storage reservoir. A pipe gallery was incorporated into the slab and foundation design as well as insulated concrete form (ICF) foundation walls. Per the Owner’s request, the architectural design used colors and materials similar to the other buildings within the surrounding commercial office park. Also, a gable roof canopy was added to the design (pictured below) to help shield the emergency backup generator from the elements. Precautions were taken to ensure proper air flow and ventilation was achieved to meet the requirements of the generator. Construction of the pump station was completed in 2015.
Tata & Howard provided the design of a 1.44 million gallon per day (mgd) water treatment plant to treat water from the Whitinsville Water Company’s Whitin Wellfield. The existing facilities consisted of a chemical injection facility and pump station, and historical high levels of iron and manganese led to water discoloration issues in the distribution system.
The new treatment facility for the Whitin Wellfield utilizes chlorine oxidation and GreensandPlus™ media filtration to remove iron and manganese from the raw water to concentrations below Secondary Maximum Contaminant Levels. The installation of 16-inch pipe between the existing facility and the water treatment facility is utilized in combination with filtration to provide contact time to achieve log removal of Giardia Lamblia (Giardia), Cryptosporidium, and viruses, if it becomes necessary in the future.
The treatment plant components include a three cell horizontal pressure filter vessel, a backwash water tank, and backwash pumping systems. The design also included a dehumidification system and the installation of crushed stone below the filter vessel and spent backwash tank. This allows for water to infiltrate into the ground and prevent puddling on the concrete floor in the event that condensation does occur on the equipment.
The Shangri La Ranch water supply, located in New River, Arizona, exceeded the running annual average maximum contaminant level (MCL) for arsenic. For the first quarter of 2015, the running annual average (RAA) was 0.0107 mg/L, and the RAA for the second quarter of 2015 was 0.0106 mg/L. The MCL for arsenic is 0.01 mg/L. Arsenic contamination within aquifers is not uncommon and is generally from natural mineral deposits. Arsenic in high enough concentrations can result in skin legions and damage to the circulatory system and cancer; therefore, it is important to monitor and minimize this contaminant from drinking water.
The Shangri La Ranch is a non-transient, non-community water system that services approximately 240 customers. The actual number of customers served varies and is dependent on the number of people that are visiting the resort during a given period of time. Tata & Howard prepared an Arsenic Treatment Report for the Arizona Department of Environmental Quality (ADEQ) to address arsenic levels in the Shangri La Ranch’s water supply. It included a summary of the existing layout and operation of the water supply wells, representative treatment provided, and recommendations for additional treatment to meet the State and Federal MCL for arsenic.
The results of the study indicated that the arsenic concentrations in Well No. 1 was low enough that blending from the existing wells would adequately reduce the arsenic concentration to below the MCL. It was also recommended that the system install two ISOLUX® cartridges, in parallel, to reduce the arsenic level in Well No. 4 to levels below the MCL prior to blending with the remaining water supplies. ISOLUX® utilizes a zirconium adsorption system to remove arsenic from water
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Tata & Howard designed and constructed the improvements to eliminate low and inadequate system pressures, construct a new source, pilot test filtration for manganese removal, design and construct required distribution system piping to connect the plant and storage tank with the system, design a new concrete storage tank, booster pump stations, and the filtration facility for manganese removal. The project was very successful and remains in great condition today.
