Iron and Manganese Removal Using Greensand Pressure Filtration
Tata & Howard conducted a Water Quality Study that reviewed the Town of North Attleboro, Massachusett’s corrosion control practices, and evaluated changes in quality, specifically the increased levels of iron and manganese. The manganese concentrations in these wells had consistently increased during the past decade. The pilot treatment study for manganese removal with greensand pressure filtration was conducted at the Kelley Wells 1 and 2 and was a success. Tata & Howard completed the design of the 2.0 mgd capacity treatment facility and provided engineering services during the construction of the facility.
The design included the installation of a SCADA system for monitoring and control of the treatment facility and two well pump stations. A second operator work station was installed at the remote Water Department office which allowed both monitoring and control of the treatment facilities from this remote site. In addition, the operator work station was linked to the existing Autocon SCADA system which continued to monitor and control the remaining water system pumping stations and storage tanks and provide tank level signals for the establishment of start/stop setpoint controls for the new treatment facility and associated wells.
Trinity Ave. Chemical Feed Pump Station, Grafton, MA
Tata & Howard provided engineering services for permitting, design, and bidding of the 1.3 mgd chemical injection Trinity Avenue Pump Station at the Trinity Avenue Wellfield. The project included an evaluation of alternatives for the access road including installation of a bridge or an open bottomed culvert; assistance with the preparation of permanent easements for the installation of utilities and roadway to the well site; preparation and submittal of an NOI to the Grafton Conservation Commission. The design included an access road, bailey bridge with abutments, double wythe block building, interior concrete painted block with wood truss roof and asphaltic shingles, installation of three (3) submersible pumps and pitless adaptors, approximately 1,800 linear feet of 6-inch and 12-inch water main, emergency liquid propane tanks and generator, instrumentation and controls, a SCADA system for the pump station and wells, and a 24-inch transmission main for 4-log removal. Security included chain link fence, gates, locks, intrusion alarms, and lighting. Tata & Howard also assisted Owner with the coordination of the installation of three phase power to site. Chemical feed at the station includes KOH for pH adjustment and chlorine gas for disinfection. Standby power was included in an outdoor enclosure. The project is currently under construction and is expected to be completed by the end of 2017.
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.
Pump Station Design and Wastewater Treatment Facility Upgrades, Barre, MA
The Town of Barre retained Tata & Howard to evaluate their existing wastewater treatment facility. Tata & Howard recommended a three phase upgrade program in order to reduce the initial impact of the construction cost on the sewer use rates. Included in the upgrade program was the design and construction of a submersible pump station that lifts the raw wastewater from an equalization tank to the biological treatment process. The pump station has a capacity of 1.2 mgd and includes variable frequency drives. The pumping station is controlled by a new SCADA system at the wastewater treatment facility. Tata & Howard also designed 8,000 linear feet of collection system sewers in the Worcester Road area of town. The project also included 500 linear feet of force main and a wet well mounted pump station. The pump station has a capacity of 200 gpm.
Water Storage Tank, Booster Pump Station, New Water Main, and Distribution System Upgrades
Town of Spencer, MA
Tata & Howard is currently providing construction administration services for a new 0.5 million gallon cast-in-place concrete water storage tank, booster pump station, approximately 12,600 linear feet of new 12-inch diameter water main, and miscellaneous distribution system upgrades. Construction of in-line isolation valves, removal of existing pressure-reducing valve (PRV) vaults, a new system wide SCADA system and new high lift pumps at the water treatment facility and well site were also included in Tata & Howard’s design. The purpose of this project is to separate the current single zone system into two pressure zones as required by an Administrative Consent Order from the MassDEP.
The creation of a two pressure zone system requires the replacement of the existing 200 horsepower (hp) pump at the Meadow Road Water Treatment Facility and 150 hp pump at the Cranberry Brook Well with lower head, high efficiency pumps and motors. The Meadow Road facility is the Town’s primary water supply source; therefore, changing of this pump requires coordination with the Department of Utilities and Facilities and the overall two pressure zone project construction sequencing to minimize the time this source is off-line.
Tata & Howard also verified the Town’s hydraulic model, which was used to select the best location for the new tank and select water main size for transmission and fire protection. The model was also used to determine the boundary line between the two pressure zones. A Capital Efficiency Plan™ is currently being prepared. Assistance will be provided, as needed, for public education of the project and during Town meetings. This project is being funded by the American Recovery and Reinvestment Act through the Massachusetts State Revolving Fund (SRF). Due to an aggressive schedule required under the funding requirements, all design; permitting associated with planning, zoning, and wetlands; and project bidding were completed and approved within a six-month period.
Water Main, Pump Station, and Storage Tank, Athol, MA
Tata & Howard provided engineering services for a water main, pump station, and storage tank for Athol Economic Development. The project specifically included the design of a new booster pump station with a chlorine injection system, emergency generator, and SCADA, approximately 3,800 linear feet of 12-inch diameter water main, and a new 210,000 gallon elevated water storage tank on Templeton Road. This project is an extension to the existing water distribution system and was designed to serve an area of commercial development, including a Market Basket, along Route 2A.