Pierce County Sewer Utility operates an Industrial Pretreatment and Accidental Spill Prevention Program to control discharge of toxic, harmful, or untreatable wastes to the sewer system. Several aspects of these programs are innovative and help to significantly maintain Pierce County's high quality effluent and biosolids.

Pierce County applies their Pretreatment and Accidental Spill Prevention Programs not only to Significant Industrial Users (SIU's), but also to all commercial dischargers. While major industries can have a major impact on a wastewater treatment plant, they are also generally very visible, stable, and with a strong pretreatment ordinance and County support, relatively easy to control.

The County has six major industries discharging to the treatment plant, but it has over 1600 commercial facilities such as photo shops, medical facilities, auto body shops, dry cleaners, lawn services, and restaurants, which when combined, can have a significant impact on the sewer system.

Pierce County's pretreatment program staff routinely inspect all major and minor commercial facilities with potential to impact the sewer utility. They track all commercial dischargers on a comprehensive database. Pretreatment staff help businesses identify hazardous components of their waste streams and then help them to find appropriate means for handling them.

Businesses with photographic processes, including x-ray development units, are educated on acceptable silver recovery options, ranging from on-site treatment units to having silver wastes hauled away by a reputable company. In follow-up inspections staff will expect to see records of treatment unit maintenance, or receipts from hauled wastes.

Pretreatment staff members also work closely with businesses to eliminate spill pathways. Businesses are strongly encouraged to permanently seal all floor drains, and to utilize appropriate spill containment systems.

A second innovative program conducted by Sewer Utility staff involves careful review of all building permits issued to customers in the sewer service area. In many sewer systems the pretreatment staff are the last to know when new facilities connect to the system. The County wants facilities to meet requirements of the pretreatment program before they are built or remodeled.

When a customer takes out a building permit, they are asked to complete a pretreatment review form to identify potential pretreatment or spill prevention concerns. Permit applications with potential adverse impacts to the sewer system are routed to pretreatment staff who review them and impose additional requirements if necessary. This program prevents the situation in which a customer builds a facility only to have pretreatment staff tell them to modify it upon the first inspection.

The County's pretreatment staff and engineers require and review engineering reports for all wastewater pretreatment systems connected to the sewer. The County has also entered into an agreement with the Washington State Department of Ecology to perform engineering review required by the state for businesses in Pierce County's service area.