Program Purpose

The purpose of the Environmental Protection Agency's (EPA) National Pretreatment Program is to protect Publicly Owned Treatment Works (POTW) and the environment from the adverse impacts that may occur when hazardous or toxic wastes are discharged into a sanitary sewer system. This is achieved mainly by regulating nondomestic (industrial) users of POTWs that discharge toxic wastes or unusually strong conventional wastes. In Washington State, the Washington State Department of Ecology (WDOE) implements this program for the Environmental Protection Agency. However, some sewer utilities such as the City of Richland's have been granted regulatory authority by WDOE and the EPA to pass local ordinances, issue their own discharge permits and run their own programs.

Pretreatment Goals

  1. To prevent the introduction of pollutants into POTWs which will interfere with the operation of the POTW, including interference with its use or disposal of municipal sludge.
  2. To prevent the introduction of pollutants into POTWs which pass through the treatment works into the receiving waters or cause upsets to the treatment works.
  3. To protect the sludge quality and improve the possibility of recycle and reuse of municipal and industrial wastewaters.
  4. To reduce the health and environmental risk of pollution by the discharge of toxic pollutants into the collection system and POTW.

Dental Waste Management

Dental offices create a variety of wastes, which need to be managed correctly to protect our health and the environment. This guide explains the Best Management Practices (BMPs) that will help dentists follow environmental laws and prevent pollution. Note that this guidance is only for dental offices on a sanitary sewer. Operatory waste should never go to a septic system, even with an amalgam separator.

Dental amalgam waste is a significant source of mercury received by sewage treatment plants. Sewage plants can’t treat the mercury in waste, so it pollutes natural water bodies and the land the solids are applied to.  For more information, consult the American Dental Association's Dental Amalgam BMPs.  

** Final Rule on Dental Categorical Standards **

The EPA's final rule related to dental categorical standards was published on June 14, 2017, in the Federal Register Volume 82, Number 113, Pages 27154-27178 (https://www.epa.gov/eg/dental-effluent-guidelines).  A one-time compliance report is required for all dental offices that discharge to the City of Richland's Wastewater Treatment Facility (40 CFR Part 441).  The required form with instructions and due dates can be found here.  The EPA has provided a fact sheet on the dental effluent guidelines, which may be helpful.       

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