SEWAGE MANAGEMENT 
by 
Ms. Cheryl Breen 
Massachusetts Office of Coastal Zone Management* 
Boston, MA 
I think Kathy Castagna has given us an excellent overview of Boston Harbor 
and Massachusetts Bay, and I would like to focus on one category of the direct discharges 
that she mentioned, the municipal sewage treatment plants, which are major contributors 
of pollutant loading into the marine environment. Specifically, I would like to discuss the 
wastewater collection and treatment system of the Metropolitan District Commission 
(MDC) (now the Massachusetts Water Resources Authority) because it is by far the largest 
of the systems discharging into Massachusetts Bay and its history can offer insight into 
the complexity of sewage management issues. Basically, I feel that if we can successfully 
solve the problems in Boston Harbor, we will perhaps be able to solve sewage treatment 
problems almost anywhere else. 
As Kathy mentioned, there are 13 municipal treatment plants which discharge 
to estuaries and marine waters along the coast of Massachusetts Bay. Many of these, 
however, are very small systems which discharge between one and three million gallons of 
sewage a day. The occurrence of occasional disruptions in the operation of these plants, 
or worse, chronic lack of compliance with discharge permit effluent limitations can 
create dramatic impacts on nearshore waters. These illegal discharges can lead to 
localized problems such as closure of shellfish beds and swimming beaches. These types 
of events should not be ignored; but especially if the plants receive little industrial flow, 
they cannot be compared to the impacts on Boston Harbor created by the major facilities 
of the MDC system. 
Of all the treatment plants discharging into Massachusetts Bay, MDC is 
responsible for contributing about 85 percent of the combined total flows. The MDC 
serves an area of 43 cities and towns in the Boston metropolitan area. It provides its 
service by operating two primary treatment plants located on Deer Island and Nut Island 
in Boston Harbor. The total flow from these plants, as Kathy mentioned, is approximately 
465 million gallons per day (mgd). In addition to the effluent discharged, the system also 
contains 108 combined sewer overflow points which discharge primarily during wet 
weather events, although some discharge even during dry weather. The most dramatic of 
the discharges from the MDC system is the discharge of sewage sludge. Once the sludge 
is separated from the effluent during the treatment process, it is put back in with the 
effluent and discharged on the outgoing tides. 
♦Current Address: Massachusetts Water Resources Authority, Boston, MA 
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