Wastewater Treatment

Each of these facilities has a wastewater discharge permit issued by the Washington State Department of Ecology or the EPA. This permit program is known as the National Pollutant Discharge Elimination System (NPDES) program.

The City of Spokane Wastewater Treatment Plant is required to sample its influent, effluent, and biosolids for PCBs as a part of its NPDES permit. The Washington State Department of Ecology requires that Liberty Lake sample for PCBs twice during the current five-year permit cycle. The other facilities are not currently required to conduct routine PCB analysis of their effluent.

Kaiser Trentwood conducts effluent analysis and follow-up monitoring of its discharge to the river. In recent years, Kaiser has taken major steps to reduce PCB concentrations in its wastewater. The company is investigating potential sources within its facility, is cleaning or replacing pipes that show contamination, and has removed contaminated sediment from its wastewater lagoon. The company is cooperating with Ecology to complete investigation of the facility under administrative orders. The company continues to monitor its effluent discharge, though sampling conducted over the years shows that trace PCBs are still present.

Kaiser also has been monitoring groundwater at the facility to determine whether or not any contaminated groundwater is reaching the Spokane River. Ecology’s Toxics Cleanup Program is overseeing this investigation, with cleanup actions to be determined following conclusion of the facility investigation work.

Other industries that are required to gain coverage under these permits include boatyards, construction sites, transportation facilities, manufacturing facilities, and sand and gravel mines. Many of these types of industries discharge stormwater to the Spokane River and/or local stormwater systems.