Deer Island Waste Water Treatment Plant
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The Deer Island Waste Water Treatment Plant (also known as Deer Island Sewage Treatment Plant) is located on Deer Island, one of the Boston Harbor Islands in Boston Harbor. The plant is operated by the Massachusetts Water Resources Authority (MWRA) and began partial operations in 1995. The facility was fully operational in 2000 with the completion of the outfall tunnel.[1]
Deer Island is the second largest sewage treatment plant in the United States.[2] The plant is a key part of the program to protect Boston Harbor from pollution from sewer systems in eastern Massachusetts, mandated by a 1984 federal court ruling by Judge Paul G. Garrity, in a case brought under the Clean Water Act.[3][4] These lawsuits culminated in Federal District Judge A. David Mazzone’s 1985 ruling that made the cleanup of the Boston Harbor a non-voluntary, court-ordered mandate.[5]
From the 1880s until 1991, the northeastern side of the island was the location of the Deer Island Prison.
The first sanitary sewer system for the Boston area, serving eighteen cities and towns, opened in 1884. It collected raw sewage on Moon Island in the harbor, and discharged it 500 feet off shore, with the ebbing tide.[1]
In 1889, the Metropolitan Sewerage District was established. Over the next fifteen years, the agency built one of the finest regional sewerage systems in the country, although it still discharged the raw sewage into the ocean.[1]
By 1940 there were three points, on Nut, Deer, and Moon islands, for the discharge of raw sewage into the Atlantic Ocean.[1] This sewage had contaminated the shellfish beds to the point that discussions of building treatment plants began. The Nut Island plant opened in 1951. The Deer Island plant opened in 1968, and the Moon Island plant was converted to standby, overflow, operation.[1]
The Metropolitan Sewerage District was reorganized into the MWRA, a larger agency, in 1985.[1] Under the federal court order,[3] MWRA completely rebuilt the treatment system between 1985 and 2000.[1] Subsequently, all sewage is treated and the effluent is discharged at the sea floor 9.5 miles (15.3 km) from shore.[1][2][6]
After nearly a decade of construction, the project ended in tragedy with the deaths of two divers in the outfall tunnel ten miles from land. The contractors who built the tunnel had completed their work and departed, taking critical life-support equipment with them but leaving the plugs in place at the far end and the $3.8 billion project at a standstill. A team of five divers drove two Humvees equipped with an unproven air supply system nine miles down the tunnel. When the tunnel became too narrow for the vehicles, three divers continued on foot using umbilicals connected to the vehicles. When they returned to the vehicles, they found the other two unconscious. The three surviving divers returned to the surface with their unconscious colleagues, who were pronounced dead at a local hospital. [7][8][9]
In 2017, MWRA, Massport, the US Army Corps of Engineers, and Eversource reached a settlement[10] to re-lay the Deer Island power cable that was blocking bigger ships from docking at Conley Terminal. The cable was laid too shallow by Boston Edison across the Reserved Channel in Boston Harbor, violating its permit and blocking the Corps from dredging a deeper shipping channel. In August 2019, a new cable was energized, requiring Deer Island to run on backup power for a few days but adding a redundant fiber optic line from South Boston. Eversource paid $17.5 million to reimburse the remaining value of the existing cable, and MWRA sewer customers are paying $97.5 million for the re-laying.[11]
