Pretreatment Program

The U.S. Environmental Protection Agency requires municipalities that operate wastewater treatment plants with capacity greater than 5 million gallons per day and which receive industrial wastewater to develop and implement a Pretreatment Program. The City’s Pretreatment Program was established in 1995.

In accordance with the federal Clean Water Act, the objectives of the City’s Pretreatment Program are to:

  • Prevent interference with treatment plant operations;

  • protect public health and safety;

  • protect the structure and integrity of the sewage collection system to ensure that personnel working in the system are safe;

  • protect the environment by preventing toxic or hazardous substances from passing through the treatment plant to the receiving water; and

  • Prevent the contamination of treatment plant sludge, which could affect sludge disposal and future sludge use.

Woodland’s Pretreatment Program consists of two related efforts: the Industrial Pretreatment Program and the Pollution Prevention Program.

The Industrial Pretreatment Program regulates discharges from Significant Industrial Users which are industries that discharge at least 25,000 gallons of wastewater per day. Significant Industrial Users have a reasonable potential to interfere with treatment plant operations, to cause pass-through and/or sludge contamination.

The Pollution Prevention Program focuses on commercial and industrial dischargers not regulated under the Industrial Pretreatment Program. Pollution prevention includes education and enforcement to prevent conditions that lead to sanitary sewer overflows.

Pretreatment Program staff also assist with Woodland’s stormwater management program by inspecting stormwater treatment devices.

An Environmental Compliance Specialist and an Environmental Compliance Inspector implement the Pretreatment Program under direction of the City’s Laboratory Supervisor.


New EPA Dental Effluent Guidelines

On June 14, 2017, US EPA promulgated new pretreatment standards to reduce discharges of mercury from dental offices. This rule applies to all offices that practice dentistry and discharge their wastewater to a Publicly Owned Treatment Works (POTW), such as the City of Woodland Water Pollution Control Facility. It does not apply to mobile units or certain dental specialties, such as: oral pathology, oral and maxillofacial radiology, oral and maxillofacial surgery, orthodontics, periodontics, or prosthodontics.

Dental offices that place or remove amalgam and discharge to a POTW, must do the following:

  • Operate and maintain one or more ISO 11143 compliant amalgam separators.

  • Follow two Best Management Practices (BMP).

    • Must not discharge scrap amalgam waste to POTWs.

    • Must not use line cleaners that have a pH level higher than 8 or lower than 6.

Additionally, dental offices, whether they place or remove amalgam, must submit a One-Time Compliance Report to their Control Authority. For Dental practices within the City of Woodland, that control authority is the City of Woodland Public Works Industrial Pretreatment Program (IPP). IPP staff will be reaching out to all Woodland dental practices and providing necessary compliance documents. For any questions regarding this document, please contact us at 530-661-2058.

For additional information go to US EPA’s Dental Effluent Guidelines web page. They have also provided a fact sheet and FAQ document.

US EPA's Dental Effluent Guidelines
US EPA Fact Sheet
US EPA FAQ Document​

For more information on the City’s Pretreatment Program, please contact us at 530-661-2065.