Environmental Issues – August 18, 2008
The US EPA has announced that, in the coming weeks, it will once again conduct full scale dredging operations to clean up PCB-contaminated sediment in New Bedford Harbour.
This year’s dredging will take place in the cove between Sawyer Street and Coffin Avenue in New Bedford. Work is expected to last for approximately eight weeks, through October 2008.
As per recent years, the EPA expects to remove about 25,000 cubic yards of contaminated sediment.
The dredged material from the harbour is pumped directly into a floating pipeline that connects the dredge to EPA’s de-sanding building located at Sawyer Street.
At the de-sanding facility, coarse material is separated from the finer sediment that, by its nature, has more PCB contamination adhering to it. The separated coarse material will be stored in a lined holding cell next the de-sanding facility.
From there, a submerged pipeline will carry the finer sediment 1.4 miles south to the de-watering facility located at Hervey Tichon Avenue and Herman Melville Boulevard.
Inside the de-watering facility, specialized presses will squeeze the excess water out of the dredged sediment before it is loaded onto wrapped and sealed train cars before leaving the facility for offsite disposal.
The EPA anticipates that the dredging operations will generate approximately 20 million gallons of water that will require stringent treatment to meet high water quality standards before being released back into the harbor. The water filtration and treatment processes also take place within EPA’s de-watering facility.
About 16,000 tons of dredged and de-watered sediment will be transported off-site by train and disposed of into a licensed PCB-landfill in Michigan.