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MWRA Water Treatment
Massachusetts water Resources Authority

 

Treatment

MWRA's licensed treatment operators treat drinking water according to strict state and federal regulations.

Water for most MWRA communities (except Chicopee, South Hadley Fire District #1 and Wilbraham) is treated at the John J. Carroll Water Treatment Plant at Walnut Hill in Marlborough. Water from the Quabbin and Wachusett reservoirs enters the plant through the Cosgrove Aqueduct. The treated water leaves leaves the plant through the MetroWest Water Supply Tunnel and the Hultman Aqueduct.
Treatment
Dose
Purpose
Ozone
1.5-4.0 mg/l
Primary disinfectant, to achieve 99.9% Giardia inactivation
Sodium bisulfite
0.0-3.5 mg/l
To remove ozone
Ultraviolet Light   Second primary disinfectant, to inactivate chemically resistant parasites such as Cryptosporidium
Sodium hypochlorite (chlorine)
3-4 mg/l
For residual disinfection, to protect water as it travels through the pipe network
Sodium hydrofluorosilicic acid (fluoride)
0.6 mg/l
For dental health
Aqueous ammonia
0.6-0.85 mg/l
To combine with chlorine to form
monochloramine for residual disinfection
Sodium carbonate
35-37 mg/l
To raise the alkalinity of the water for pH buffering; to minimize lead and copper leaching from home plumbing
Carbon dioxide
4.5-8.5 mg/l
To adjust pH to final level

 

Water Treatment Steps for Chicopee Valley Area Communities
Water for Chicopee, South Hadley Fire District #1 and Wilbraham is treated at the William A Brutsch Water Treatment Facility in Ware, Massachusetts. Water from the Quabbin Reservoir is treated at the facility and treated water water leaves the plant through the Chicopee Valley Aqueduct. Each community further treats the water to reduce the chances that lead and copper from home plumbing could dissolve into tap water.
Treatment
Current Dose
Purpose
Chlorine   Primary disinfectant, to achieve 99.9 percent Giardia inactivation, as well as residual disinfectant
Ultraviolet Light   Second primary disinfectant, to inactivate chemically resistant parasites such as Cryptosporidium

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Updated September 1, 2015