|  | Public Health Safety | Environmental Health

Wastewater Discharge Authorization

The National Pollution Discharge Elimination System (NPDES) program was established by the Clean Water Act (CWA) to control storm water and point source discharges. Section 402 of the CWA states that it is mandatory to acquire an NPDES permit for any pollutant discharge from a point source to any navigable U.S. surface water and beyond. The United States Environmental Protection Agency (USEPA) is mandated by CWA to enforce and establish regulations for municipal treatment plants and industrial dischargers. NPDES programs in all states came up with discharge limitations of various pollutants including toxic, conventional and non conventional.

  1. Categorical Discharge

    • USEPA formulated categorical discharge limitations pertaining to specific industries included in the 40 CFR list. If the wastewater from your facility is produced from the listed operations, then you are supposed to acquire a wastewater discharge permit. It is necessary to discuss with the local authority issuing the permit since there are certain exceptions. Both local limits and federal categorical limitations cover the categorical discharges, and stringent limitations are included in the permits. New industries are periodically added to the 40 CFR list, thus it is important to check with your local authority to ascertain if your industry is within the categorical standards.

    Indirect Discharges

    • Indirect discharges refer to discharges of contaminated storm water and industrial waste water to a sanitary sewer. Regulation of these discharges is according to the industrial pre-treatment limitations. Typically, biological treatment is used in the municipal treatment plant to remove Total Suspended Solids (TSS) and Biochemical Oxygen Demand (BOD). Industrial pollutants might interfere with the biological treatment, leading to a process failure, cause damage to the equipment or harm the workers. Therefore, depending on the type of your discharge, a discharge authorization or permit may be necessary. USEPA formulated the indirect discharge national pre-treatment standards identified in the 40 CFR 403.5.

    Local Limits

    • There are limits established by the local authority taking into consideration the specific conditions of their treatment system and also their discharge permit. The CWA 40 CFR 403.5 (3) empowers the local authority to implement the local limits. Local limits cannot be less than the federal limitations, but are allowed to be more stringent. Local limits differ across the states so it is necessary to check with your local authority.

    Direct and Storm Water Discharge

    • Direct discharges refer to the release of contaminated storm water or industrial water into surface water as well as storm or ground sewer without going through Publicly Owned Treatment Works (POTW) first. A permit for direct discharge is required and it is more stringent than the indirect discharge permit. You can get details for this permit from the environmental department in your state. Regulation is also extended to the un-contaminated storm water discharges, thus you should get in touch with your local authority to find out about specific requirements.

Environmental Health - Related Articles