EPA's Draft Permit for MWRA's Deer Island Treatment Plant Outfall and Combined Sewer Overflows, 2023

Announcement of Draft Permit Availability
Executive Summary of Permit

INTRODUCTION:
The Environmental Protection Agency (EPA) is re-issuing the Massachusetts Water Resource Authority's (MWRA) National Pollutant Discharge Elimination System (NPDES) Permit to discharge treated wastewater from 43 member communities through the Deer Island Treatment Plant to Massachusetts Bay, four combined sewer overflow (CSO) treatment facilities and 47 CSO discharges in Boston Harbor and surrounding tributaries.

The draft permit proposes rigorous conditions to ensure the protection of Massachusetts and Cape Cod Bays. In addition, the 2023 draft permit continues to require that MWRA monitor the water quality in Massachusetts and Cape Cod Bays.

HISTORY OF THE PERMIT:
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 2000 permit issuance set the conditions on the discharge from the $3.8 billion facilities. The 2000 permit also covered discharges from combined sewer overflows (CSOs) to the Boston Harbor and surrounding tributaries.

The 2023 draft permit was released for public comment on May 31, 2023, and the originally 60-day public comment period was scheduled to close on July 31, 2023. The public comment period has been extended by 30 days and will now close on August 20, 2023. A virtual public meeting will be held on July 12, 2023, at 7 PM. The public meeting will be followed by a public hearing on July 12, 2023, at 8 PM.

OUTFALL LOCATION:
The offshore outfall site was proposed by the MWRA and was approved by EPA and the MassDEP 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 outfall location is in 110 feet of water in Massachusetts Bay and offers an initial dilution of 70 to 1. 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 MassDEP determined, during the State's antidegradation review for the 2000 permit, that the Massachusetts Bay outfall site is the least environmentally damaging alternative for the treated wastewater discharge.

ENDANGERED NORTHERN RIGHT WHALES:
The National Oceanic and Atmospheric Administration (NOAA) has identified Cape Cod Bay and Stellwagen Bank as part of the range of the North Atlantic right whale (Eubalaena glacialis), one of the most endangered of all large whale species. NOAA Fisheries estimates that fewer than 350 North Atlantic right whales remain. The whales are known to forage year-round in this area, which has also been designated as North Atlantic right whale critical habitat (Critical Habitat Unit 1: Feeding Area).

Secondary treatment at Deer Island has greatly reduced potentially harmful pathogens, metals, and organochlorine compounds like polychlorinated biphenyls (PCBs). A careful evaluation under the Endangered Species Act (ESA) regarding the impact of the outfall on the North Atlantic right whale resulted in a 1993 Biological Opinion by NOAA Fisheries that determined the outfall is not likely to jeopardize the species. The 2023 draft permit proposes monitoring to ensure that any impacts are not likely to adversely affect protected species. As part of the re-issuance, EPA will reinitiate Endangered Species Act (ESA) consultation with NOAA Fisheries for the North Atlantic right whale and its critical habitat, as well as for the federally endangered fin whale, the threatened/endangered Atlantic sturgeon, the endangered shortnose sturgeon, the threatened green and loggerhead sea turtles and the endangered Kemp's ridley and leatherback sea turtles.

PROTECTION OF MASSACHUSETTS AND CAPE COD BAYS THROUGH AMBIENT MONITORING AND CONTINGENCY PLAN:
The 2000 permit included stringent limits and testing requirements for the wastewater discharge after full secondary treatment at Deer Island. The MWRA was 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 of the discharge from the ocean outfall has been compared with the 7 years of pre-discharge monitoring data collected by MWRA. The data has found that the treatment plant and ocean outfall are performing as expected.

The 2023 draft permit requires MWRA to continue to monitor the water quality of Massachusetts and Cape Cod Bays under a revised Ambient Monitoring Plan with a focus on new or remaining questions related to the impact of the discharge on Massachusetts and Cape Cod Bays.

CLOSING OF EXISTING NEARSHORE OUTFALL SYSTEM:
The 2000 permit required the MWRA to maintain the existing Boston Harbor outfall system from the DITP, so that the nearshore discharge will be physically available for use if the ocean outfall was found to cause environmental harm. Over 20 years, ambient data has shown that the ocean outfall is performing as predicted and has not adversely affected Massachusetts or Cape Cod Bays. The nearshore outfalls are no longer authorized under the draft permit as they are no longer a necessary contingency option.

POLLUTION PREVENTION:
EPA and MassDEP strongly encourage efforts to prevent pollution at the source. The draft permit requires that the MWRA update and continue to make available their Household Hazardous Waste booklet in both hard copy and on-line formats. The update to the booklet and MWRA's school curriculum shall include information on the sources and proper disposal of contaminants of emerging concern: Pharmaceuticals and Personal Care Products (PPCPs), PFASs and microplastics.

OPERATION AND MAINTENANCE OF TREATMENT FACILITIES AND SEWER SYSTEM INFRASTRUCTURE:
The 2023 draft permit includes updated operation and maintenance requirements, consistent with state regulations, in order to ensure that sewer system infrastructure, such as sewer pipes and pump stations, and the treatment facilities are properly operated, maintained and resilient. These include contingency measures, such as maintaining alternative power systems in case of power outages, preventing groundwater and rainwater from entering the sewer system and evaluating and implementing measures to maintain system operation in the event of major storm and flood events.

The 2023 draft permit applies the operation and maintenance requirements to the 43 satellite communities that contribute wastewater to the MWRA Deer Island Treatment Plant. These communities are included in the permit as "co-permittees" and are only responsible for the operation and maintenance of the collection systems that they own and operate. Co-permittees are not responsible for operation of the treatment facility or for meeting Deer Island effluent limits. The 2023 draft permit includes annual reporting requirements for co-permittees.

COMBINED SEWER OVERFLOWS (CSO):
The permit includes conditions related to combined sewer overflows, such as a requirement that any discharges from such overflows must not contribute to the exceedance of water quality standards. The 2023 draft permit also incorporates CSO requirements for the four satellite collection systems (Boston Water and Sewer Commission, Cambridge, Chelsea and Somerville) that were previously regulated in separate permits.