Bellemont, AZ Water Treatment

bellemont-water-system-az-chlorine-injection-768x399Tata & 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.

Raw Water Transmission Main Replacement in Stamford, CT

awc-laurel-street-raw-water-mainOwner: 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.

Interceptor Sewer, Danbury, CT

interceptor_sewer
Jacking a 48-inch steel casing under I-84 in Danbury, CT

The Oakland Avenue sanitary sewer project consists 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 will alleviate 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. Construction is currently underway and the project is expected to be completed by the end of this October. The new sewer line installation will complete an interceptor project that was constructed in 1994.

Water Distribution System Evaluation and Tank Design, Paxton, MA

Town of Paxton, MA

The new tank was completed in 2015
The new tank was completed in 2016.

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:

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Water Treatment Facilities, Canton, MA

Pecunit Street and Neponset Street, Canton, MA

Canton MA water treatment facilityThe 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

Falmouth, MA

Falmouth_Crooked_Pond_Water treatment facilityTata & 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.

Distribution System Water Quality Study, Norwich, CT

Norwich Public Utilities, Norwich, CT

NorwichCT_MainStTata & 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.

On-Call Water Engineering Services, Franklin, NH

City of Franklin Municipal Services Department, Franklin, NH

FranklinNH_water treatment facilityTata & 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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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.

Unidirectional Flushing Program, Capital Efficiency Plan™, and Water Main Design, Melrose, MA

Unidirectional Flushing
Tata & Howard provided assistance during the City’s unidirectional flushing program.  As part of the work, Tata & Howard recorded the flow from the hydrants, noted any changes in the plan, and noted any defective hydrants or valves.  When completed, a summary report outlining the total usage of water and recommended improvements to the flushing program was provided.

MelroseMAHPWater Mains and Capital Efficiency Plan™
Tata & Howard also provided design and construction services for approximately 5,600 feet of new 8-inch water main and approximately 950 feet of new 12-inch water main throughout the City. Plans were created using available GIS data from the City and field verification. These water mains also included crossing two MWRA transmission mains and crossing the Lynn Fells Parkway. The Lynn Fells Parkway crossing required permitting with the Department of Conservation and Recreation and a traffic management plan. This work was funded through the MWRA. As part of the project, Tata & Howard updated and verified the City’s existing hydraulic model, which has over 80 miles of water main.  Work included two days of fire flow tests throughout the City and allocation of demands using up-to-date billing and parcel data. The locations of the new water mains were selected based on preliminary recommendations identified in the Capital Efficiency Plan™ that was prepared by Tata & Howard. 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, 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.

Download a whitepaper detailing a comprehensive summary of the UDF by clicking the link below:

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