Boston Harbor and Massachusetts Bay
MWRA Environmental Quality
Boston Harbor Project
1986 TO 2000 THE BOSTON HARBOR PROJECT GRADUALLY REDUCED TREATMENT PLANT
DISCHARGES TO THE HARBOR
under a federal court order, MWRA
was created to plan and construct new sewage treatment facilities to end the discharge of untreated and partially treated sewage to Boston
Harbor. The “Boston Harbor Project,” as it was called, included four major
1. Pelletizer Plant: Facilities
at the Fore River shipyard in Quincy to process sewage sludge into commercial
fertilizer pellets, ending the discharge of sludge into the harbor.
2. A new
secondary wastewater treatment facility, the new Deer Island Treatment
Plant (DITP), to replace the failing and undersized primary treatment
plants at Deer Island and Nut Island (NITP).
3. A tunnel
from Nut Island to DITP to transport South System sewage to DITP for secondary
treatment, enabling flows from throughout MWRA’s service area to receive
secondary treatment and greatly lessening pollution to the harbor.
4. An outfall in Massachusetts Bay to discharge treated effluent 9.5 miles offshore into Massachusetts
Bay, increasing dilution and minimizing potential environmental impacts
in the bay.
to taking on these major construction projects, MWRA started addressing the
problem of combined sewer overflows (CSOs), which discharge a mixture
of stormwater runoff and sewage directly into the harbor during heavy
rainstorms. In the 1980s, 88 CSOs in the harbor and its tributary rivers
discharged an estimated 3.3 billion gallons of partially treated or raw
combined sewage annually.
More on the State of Boston Harbor