Today, MWRA breaks ground in Marlborough for the new Walnut Hill Water Treatment Plant, a $260 million project to improve the quality of the drinking water supplied to 2.2 million people in greater Boston.

The new plant will have the capacity to treat more than 400 million gallons of water per day drawn from the Wachusett Reservoir. Treatment processes at the plant will include ozonation, a modern method for water disinfection.

"For ten years this plant has been in planning and design to assure that the appropriate processes for water treatment here in greater Boston can be delivered to ratepayers in a cost-effective fashion," said MWRA Executive Director Douglas B. MacDonald. "MWRA's board of directors chose the treatment technology for the plant last October, after an exhaustive review of the water treatment needs of the MWRA system, which included broad participation by water quality professionals, public officials and concerned citizens.

"Water from the new plant will meet every state and federal drinking water standard now on the books or those expected to be adopted ," he said.

When the new plant is completed, existing disinfection facilities at various MWRA locations will be discontinued. They include the Cosgrove Disinfection Facility in Clinton, the Interim Corrosion Control Facility in Marlborough, disinfection facilities at community systems west of Norumbega Reservoir in Weston, and, in combination with the new Norumbega Covered Reservoir and the Loring Road Tanks, it will replace disinfection facilities at the Norumbega and Weston Reservoirs. These changes will mean, among other improvements, that MWRA will be able to drastically reduce the amount of chlorine used in the water treatment process.

The plant is just one part of MWRA's 10 year, $1.7 billion Integrated Water Supply Improvement Program. In addition to the new plant, MWRA is building the MetroWest Water Supply Tunnel, a deep rock water tunnel that will stretch 17.6 miles from Marlborough to Weston; the construction of five new covered water storage tanks that will replace existing open reservoirs to protect the treated water; increased watershed protection measures around MWRA's two source reservoirs, the Quabbin and Wachusett; and undertaking an extensive program to rehabilitate the large pipelines that deliver water to MWRA communities.

The construction of the large new plant requires several significant construction contracts. The first contract, which officially begins on the day of the groundbreaking, includes clearing and earth excavation, a 50 million gallon reinforced concrete water storage tank, large diameter piping, access roads, and a bridge over the Wachusett Aqueduct forebay channel. The construction contractor for the first contract is Barletta Heavy Construction, Inc. The plant has been designed by Camp, Dresser & McKee Inc.. ICF Kaiser will serve as contract manager for MWRA for the plant.

The plant is scheduled to go online in 2004.