Tech Corner: Wastewater Practices - General requirements

Sanitary wastewater discharges regulated by the Washington Suburban Sanitary Commission (WSSC) and the Maryland Department of the Environment (MDE) establish specific conditions under which wastewater can be discharged. This fact sheet summarizes general regulatory requirements for wastewater discharge and identifies compliance management practices for facility personnel.

Applicable Regulation

·         The Plumbing and Gas Fitting Regulations

·         40 CFR Part 403- General Pretreatment Regulations for Existing and New Sources of Pollution

·         COMAR 26.04- Regulation of Water Supply, Sewage Disposal and Solid Waste

General: The WSSC regulations limit the types of materials that may be discharged into the sanitary sewer and may require pretreatment and facility permits on a case-by-case basis. Primary contaminants that must be kept out of the wastewater stream include volatile organic compounds, heavy metals and acidic or caustic discharges.

Specific discharge prohibitions: A detailed list of prohibited discharges, including numerical limits for heavy metals, pesticides, solvents, organic and other compounds is included in the above-referred WSSC regulation. The following is an abbreviated summary of prohibited discharges:

·         Wastewater with a pH lower than 6.0 or higher than 10.0;

·         Any radioactive liquid having concentrations greater than that allowed under State law;

·         Total toxic organics (e.g., acetone, benzene, toluene, xylene) having a total concentration greater than 2.13 milligrams per liter;

·         Non-contact cooling water, industrial process wastewater or uncontaminated cooling or industrial wastewater;

·         Substances such as fuel and lube oils, gasoline, kerosene, benzene, toluene, xylene ethers, alcohols, etc. which could cause a fire or explosion in the sewer system;

·         Noxious substances that could cause a public nuisance or toxic fumes;

·         Hazardous waste and filter backwash;

·         Liquids or vapors with a temperature greater than 150 degrees Fahrenheit;

·         Glycol compounds.

Training

Personnel involved with wastewater discharge activities should be trained to comply with applicable requirements.

Reporting

WSSC must be notified of any non-compliant or accidental discharges including spills, upsets, slug loads, etc.

Inspections

Inspections may be required by WSSC on a case-by-case basis. Wastewater pretreatment systems must be inspected and maintained according to applicable regulations.

Recordkeeping

Wastewater pretreatment system operating, maintenance, and calibration logs should be maintained for three years. Discharge reports should also be maintained for three years.