Publication Summary

Announced Basin Class II Inspections were conducted at two municipal wastewater treatment plants (WWTPs) and three industrial WWTPs in the Spokane River basin during March 22-24, 1993. A separate inspection report was written for each discharger in the basin; this report is based on the inspection conducted at the Kaiser Aluminum and Chemical Corporation (Kaiser) WWTP.

Announced Basin Class II Inspections were conducted at two municipal wastewater treatment plants (WWTPs) and three industrial WWTPs in the Spokane River basin during March 22-24, 1993. A separate inspection report was written for each discharger in the basin; this report is based on the inspection conducted at the Kaiser Aluminum and Chemical Corporation (Kaiser) WWTP.

The plant was operating well at the time of inspection. The industrial wastewater (002) and sanitary wastewater (003) discharges to the facility wastewater lagoon met all permit requirements. Discharge from the lagoon (001) to the Spokane River also met permit requirements for total suspended solids (TSS), oil and grease, aluminum, chromium, zinc, cyanide, and pH. Aluminum, cadmium, copper, lead, and zinc exceeded water quality criteria in both lagoon effluent and in the receiving water upstream from the discharge point, but since river water is the primary source of plant process water supply, the discharger's NPDES permit limitations are applied on a basis of net loading. A concurrent metals study progressing in the Spokane River basin should be consulted concerning potential effluent metals toxicity in the receiving water. Other recommendations are included in this report.