Toxic Reduction and Control (TRAC)

A sewer user whose process results in a Discharge containing one or more substances in a concentration or quantity requiring Pretreatment to meet the requirements of 360 CMR 10.021 through 10.025 and who does not have a Group, General, or Combined Permit for the discharge.

A sewer user whose process results in a Discharge containing one or more substances regulated by the 360 CMR 10.021 through 10.025 at a concentration or quantity not requiring Pretreatment to meet 360 CMR 10.021 through 10.025 and who does not have a Group, General, or Combined Permit for the Discharge.

A sewer user whose process results in a Discharge not containing a substance regulated by 360 CMR 10.021 through 10.025 and who does not have a the MWRA and who does not have a Group, General, or Combined Permit for the Discharge.

An SIU without an Industrial Waste Discharge to the Authority Sewerage System or any tributary thereto.

A person with a Septage Discharge Permit.

A person with a General Permit for Low Flow and Low Pollutant.

A Person with a Temporary Construction Site Dewatering P, even if the Discharge might also meet the definition of another category.

A Person with a Group Permit for Photo Processing and Printing Operations.

A Person with a Group Permit for Food Processing.

A Person with a Combined General Permit for Low Flow and Low Pollutant and Group Permit.

A Person with a Group Permit for Dental Discharges.

Molybdenum is a metal which is commonly used as a corrosion inhibitor in industrial, commercial, and residential cooling towers, and has been measured at elevated levels during the cooling season in MWRA fertilizer pellets. While these levels are well below current federal standards, they exceed the Mass. DEP highest-quality levels for unrestricted land application.

TRAC has been working on a voluntary program with suppliers of corrosion control chemicals to switch their corrosion control agents containing molybdenum to those that do not contain them. To date, this program has helped reduce molybdenum influent levels by approximately 40% since 1995.

Mercury

    

Mercury is a heavy metal which (in certain chemical forms) can be highly toxic and is known to bioaccumulate (build up) in fish and (potentially) humans and marine mammals who consume these fish.

While mercury is found in very small amounts in a number of products, MWRA has identified hospitals, dental facilities (using dental amalgams) and several commercial and household products (cleaners and disinfectants) as key sources to our system. Mercury also is contributed in significant amounts by rain events, through atmospheric deposition of mercury which is released as a result of municipal incinerators and fossil fuel plants.

TRAC has been working with known mercury sources on a variety of programs, including extensive research with Boston- area hospitals on pretreatment options and control options for mercury disposal and control in hospital facilities. In addition, a pollution prevention outreach program to test systems that collect and recycle dental amalgam is being implemented.

MWRA is also working nationally with other city wastewater treatment plants to address the mercury sources found in many commonly used industrial and commercial products, through education and outreach.

Copper levels in MWRA's fertilizer pellets have sometimes exceeded the most-stringent state standards for reuse. Because MWRA's water supply is somewhat corrosive to water pipes, copper is leached from residential and other service pipes, eventually ending up in MWRA's wastewater. Copper can also be contributed through improper treatment and discharge of vehicle washing and cleaning activities. It is also found in many commercial and industrial chemicals, such as root-killers and paint pigments.

MWRA has undertaken a multi-pronged effort to address copper. Current actions include:

Increased sampling of industrial permittees for copper

Optimized corrosion control of the water supply

Testing of currently unregulated sources (e.g. car washes, boilers, cooling towers) to determine copper levels and (if necessary) additional regulatory controls

Lead

Lead is a heavy metal which has been found in MWRA pellets at concentrations which sometime exceed the Mass. DEP's most stringent standards for reuse. Lead, like copper, is commonly used in older residential and service pipes, and is thus susceptible to leaching into the water supply. Lead may also be contributed from storm water runoff as well as some types of metal processing operations.

TRAC decreased the allowable limit for industrial dischargers from 0.4 mg/l to 0.2 mg/l in 1992, and MWRA Waterworks Division installed an Interim Corrosion Control Facility in 1997. At this facility, Sodium Carbonate (Soda Ash) and CO2 (Carbon Dioxide) are added to increase the water's buffering capacity. MWRA has also adjusted the pH of the water. These changes are helping to reduce the lead levels found in tap water (and eventually discharged to Deer Island).

EPA and the National Marine Fisheries Service (NMFS) have expressed concern that PCBs (polychlorinated biphenyls) can harm fisheries and marine mammals. Current levels of PCBs in Mass Bay exceed EPA human health criteria. As a result, PCBs are a key focus of the proposed new discharge permit for the Deer Island Treatment Plant, and TRAC has prepared a pollution prevention (P2) plan to control and reduce the amounts of PCBs discharged to the sewer. This plan is under review by EPA and DEP.

MWRA currently prohibits the discharge of PCBs, and these pollutants are not generally found in any current industrial processes. Although Deer Island influent sampling generally does not detect PCBs, they are assumed to be contributed through contaminated groundwater and storm water runoff. (EPA estimates that 85% of the PCB loading to Mass Bay comes from atmospheric deposition.) TRAC's P2 plan is expected to focus on cooperative efforts to find groundwater sources to the MWRA sewer and a sampling program to ensure that potential commercial and industrial sources are adequately controlled.