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EPA's/MassDEP's Permit for MWRA's Outfall and Combined Sewer Overflows, 1999

Announcement of Issuance Executive Summary of Permit

The Environmental Protection Agency (EPA) and the Massachusetts Department of Environmental Protection (DEP) are issuing the Massachusetts Water Resource Authority's (MWRA) National Pollutant Discharge Elimination System (NPDES) Permit to discharge industrial wastewater and domestic wastewater from 43 member communities through the Deer Island Wastewater Treatment Plant. The permit is issued jointly under the federal and state Clean Water Acts, and marks a key milestone in years of effort to address pollution in Boston Harbor. After the wastewater receives secondary treatment at the new Deer Island facility, the effluent will travel through an ocean outfall tunnel nine and a half miles offshore into Massachusetts Bay.

In addition to the strict limitations imposed on the wastewater discharge, this permit includes rigorous conditions to ensure the protection of Massachusetts and Cape Cod Bays. This permit is the most comprehensive ever imposed on a public discharger. The permit includes unprecedented ambient monitoring requirements to assess any unanticipated adverse effects and to address concerns about shellfish resources, Right Whales and other protected species; innovative provisions for water conservation and reduction of infiltration and inflow, to control future wastewater discharges into the Bay; stringent pollution prevention and best management practice requirements; and a first-of-its-kind contingency plan to address any unexpected problems.

In response to lawsuits filed in 1982 and 1985, the newly-established MWRA proposed the construction of secondary treatment facilities on Deer Island. The 13 year schedule was memorialized in a federal court order. The issuance of this permit will set the conditions on the discharge from the $3.8 billion facilities, with secondary treatment currently operational and the completion of the effluent outfall tunnel expected in late 1999. Although this permit also covers discharges from combined sewer overflows (CSOs) to the Charles River and other locations, this permit will be modified in late 1999 to reflect the $450 million CSO control plan currently being implemented by the MWRA.

The draft permit was released for public comment in February of 1998, with public hearings in Boston, Nahant, and Barnstable, as well as numerous public informational meetings. The permit was revised in response to the public comments, and the final decision may be appealed to the DEP and the EPA for administrative hearings within 30 days of its issuance. The term of this permit is five years.

The offshore outfall site was proposed by the MWRA, and was approved by EPA and the DEP based on an evaluation of alternatives through both the National and the Massachusetts Environmental Policy Acts reviews conducted in 1988. During the siting process, EPA required potential outfall sites to provide a high level of initial dilution and to allow sufficient distance from the shoreline so that pollutants would not reach the shoreline on the next incoming tide, as well as avoiding proximity to public beaches. The existing outfall site, located at the mouth of Boston Harbor, does not meet any of these criteria.

The new outfall location is in 100 feet of water in Massachusetts Bay and offers an initial dilution of 70 to 1, as compared to the 30 feet of water and a dilution of 14 to 1 that is available near Deer Island. The size and circulation of Massachusetts Bay offers increased mixing of the effluent, and the offshore location ensures that even shoreward currents will not transport effluent to beaches or shellfish beds - either near Boston or Cape Cod. The DEP determined, during the State's antidegradation review, that the Massachusetts Bay outfall site is the least environmentally damaging alternative for the treated wastewater discharge.

The federal government has identified Cape Cod Bay and Stellwagen Bank as critical habitat for the Northern Right Whale, the most endangered of all whale species with only 300 remaining in the North Atlantic. A careful evaluation under the Endangered Species Act regarding the impact of the outfall on the Right Whale led to a formal conclusion by the National Marine Fisheries Service that the outfall is not likely to jeopardize the species. Secondary treatment at Deer Island will greatly reduce potentially harmful pathogens, metals, and organochlorine compounds like polychlorinated biphenyls (PCBs). Although the habitat areas, which are used seasonally for feeding, are more than 16 miles from the new outfall location, the permit is conditioned to require monitoring to ensure that there will be no impacts on the species.

This permit includes stringent limits and testing requirements for the wastewater discharge after full secondary treatment at Deer Island. The MWRA is required to conduct an extensive water quality monitoring program, called the Ambient Monitoring Plan. The Ambient Monitoring Plan provides for a continuous assessment of chemical, physical, and biological conditions around the ocean outfall location, at far field locations in Cape Cod Bay, and near the Stellwagen Bank National Marine Sanctuary. The results of sampling after initiation of the discharge from the ocean outfall will be compared with the 7 years of pre-discharge monitoring data collected by MWRA. This data will serve as the baseline against which to measure all future potential outfall impacts, such as red tide or any threat to the rare Right Whales known to frequent the area.

Results of the monitoring plan are linked to actions in a Contingency Plan, which includes water quality triggers and thresholds for corrective action by the MWRA. If a warning level exceedance occurs, the MWRA must evaluate the cause and effect and develop a response plan, such as conducting additional monitoring and/or adjusting plant operations. The MWRA will maintain an Internet Web Page that will provide free public access to all monitoring information, and EPA will maintain an electronic mail distribution system which will provide rapid dissemination of key monitoring data to all interested parties.

An integral aspect of the Monitoring and Contingency Plans is the creation of the Outfall Monitoring Science Advisory Panel (OMSAP). This panel of independent scientists, selected for their expertise within their respective fields and for their specialized knowledge of Massachusetts Bay and the Gulf of Maine, will provide recommendations to EPA and the DEP based on data from the Ambient Monitoring Plan and any special studies performed by the MWRA.

The MWRA is required to maintain the existing outfall system, so that the nearshore discharge will be physically available for use. The permit also requires the MWRA to submit a plan describing how alternative discharge scenarios (including discharge through existing Deer Island outfalls, if necessary) could be implemented. These alternative discharge scenarios must be considered as potential responses within the MWRA's contingency plan.

From an environmental perspective, diversion of the discharge back into Boston Harbor would be an option only if the Boston Harbor outfall provided superior water quality benefits or were necessary to remedy other environmental harms, for example to prevent harm to protected species. Because of the benefits provided by the outfall location in Massachusetts Bay in providing dilution, mixing, and distance to shore, the possibility that diversion of the discharge back to the Harbor would be environmentally desirable is remote.

Specific provisions to promote water conservation were proposed by EPA as a means to reduce the volume of the wastewater discharge. This is the first NPDES permit of this type to include water conservation requirements. EPA and the DEP believe that implementing a watershed-based assessment and permitting approach requires the concurrent consideration of both water supply and wastewater issues. The MWRA has already developed and is implementing a water conservation program. The requirements incorporated into this permit are intended to build upon the MWRA's existing program, as well as ensure that past activities continue to be performed by the MWRA and its member communities. For example, the MWRA must consider a variety of conservation measures, from 100% metering to educational programs, as components of a comprehensive water conservation plan.

EPA and DEP strongly encourage efforts to prevent pollution at the source. The final permit requires that the MWRA develop and implement a pollution prevention plan that encompasses all users of the MWRA system-industrial, commercial, and residential. There is special focus on MWRA's efforts to reduce PCBs, including monitoring of industries where PCBs are typically found and requiring implementation of spill containment measures.

Infiltration/inflow (I/I) is water that enters sewers either from high groundwater, surface runoff, or pumping from basements that is carried to a wastewater treatment plant but would not otherwise require treatment. Based on a review of historic wastewater flow records for the MWRA's regional wastewater system, I/I contributes to over one-half of all the flows in the regional system and this percentage increases dramatically during significant rainfall events and snow melt conditions. Sanitary sewer overflows (SSOs) occur when the hydraulic capacity of the sewer system is exceeded and raw sewerage overflows from the system.

Although transport and treatment of I/I flows can be costly, the reduction of I/I by sewer rehabilitation is also expensive and most of the sewer pipes are municipally owned. The MWRA has implemented extensive actions to reduce these extraneous flows, but EPA and the DEP are persuaded that more can be accomplished regionally to control I/I and SSOs. The permit requires the MWRA to evaluate methods such as rate structures and offset programs to reduce I/I and SSOs, and to work with member communities through a recently formed Task Force to produce a plan for further improvements. The plan, with allocation of responsibilities between the MWRA, member communities, and the DEP, will form the basis for a Memorandum of Understanding (MOU) with the DEP to ensure that progress continues.