Pretreatment Program for Industry

The wastewater discharged by industries or commercial facilities is more challenging to treat than residential wastewater. It can be contaminated by harmful or toxic substances that can’t be removed by the normal wastewater treatment process [link to treatment process page] Wastewater from industrial processes can contain copper, lead, mercury, nickel and other heavy metals and organic pollutants.

Since NSD’s sewage collection and treatment systems have not been designed to treat them, industrial wastes can damage sewers and interfere with the operation of the treatment plant or pass through the system untreated, resulting in pollution of the Napa River.

To protect the treatment plant and water quality, Napa Sanitation District implements a Pretreatment Program. This program monitors industrial dischargers and requires them to use proven pollution control techniques to remove pollutants from their wastewater BEFORE discharging it to the sewer system. This practice is known as “pretreatment”.

The District’s Pretreatment Program has four tactics:

  • Pollution PreventionPollution prevention materials provided by the District educate all sewer users (residential & commercial) about ways to reduce pollution in their wastewater.
  • Best Management Practices: Best Management Practices (BMPs) for specific industries/businesses contain proven practices for reducing pollution in wastewater. Some BMPs are mandatory, while others are recommended.
  • Permits: Some industries must receive a permit from the District in order to discharge their wastewater. The permit contains pretreatment and water quality monitoring requirements.
  • Inspections: District inspectors visit certain businesses on a regular basis to ensure that pollution prevention BMPs are being implemented and to provide information.