Westford is a rapidly growing community outside of Boston and receives its water from eight groundwater wells. While the town has an ample raw water supply; treatment is needed to meet increasingly stringent water quality standards. After evaluating several treatment options, the Town and engineer chose to work with Tonka Water to customize solutions for the Forge Village and Nutting Road treatment plants. Each plant has a design capacity of three million gallons per day. The plants were successfully commissioned in 2003.
Each cutting-edge treatment plant consists of onsite hypochlorite generation for disinfection and iron oxidation, potassium permanganate feed for manganese oxidation and filtration. Each plant has three 10’ diameter x 37’ long OptaCell™ pressure filters using a dual-media filter bed of manganese greensand and anthracite. The anthracite removes the larger iron and manganese precipitates, while the greensand removes the smaller manganese dioxide solids that pass through the anthracite.
The system is controlled by Tonka Water’s PLC-based automatic control panels which have been customized to automatically backwash the filters by loss of head, time, or operator initiation. The duration of the backwash and other functions are selectable and adjustable by the operator through an Allen-Bradley PanelView 1000-color touchscreen.
The raw water analysis summarized below reflects high concentrations of iron and manganese. The treatment process has been highly effective in delivering quality water as indicated below.
|Raw Water||Finished Water|
|Iron (Fe)||1.8 mg/L||0.01 mg/L|
|Manganese (Mn)||0.7 mg/L||0.02 mg/L|