Publication Summary

A Class II Inspection was conducted August 21-23, 1995 at the Washington Water Power Company Kettle Falls Generator Station (Kettle Falls), located on the Columbia River′s Lake Roosevelt near Kettle Falls in Stevens County, Washington. The inspection investigated the Kettle Falls combined process wastewater and cooling water treatment system.

A Class II Inspection was conducted August 21-23, 1995 at the Washington Water Power Company Kettle Falls Generator Station (Kettle Falls), located on the Columbia River′s Lake Roosevelt near Kettle Falls in Stevens County, Washington. The inspection investigated the Kettle Falls combined process wastewater and cooling water treatment system.

Visual inspection discovered a substantial algae bloom in the retention basin. General chemistry results identified oxygen demand parameter increases across the basin and suggest that these increases were the result of the algae bloom. It is recommended that Kettle Falls take steps to reduce algae growth in the retention basins. Kettle Falls totalizer result was 92% of NPDES monthly average permit limit, and investigation of the totalizer measurements by Ecology doppler flowmeter estimated that effluent flows exceeded that limit. Kettle Falls should recalibrate their meter to ensure accuracy and evaluate whether future flows will remain within the permit limit.

Although inspection effluent temperatures exceeded permit daily average limits, dilution zone modeling indicated that these temperatures would be reduced to ambient temperatures at the edge of the chronic dilution zone. Several organic compounds were identified as possible contaminants in the plant cooling water, and it is recommended that Kettle Falls identify and if possible eliminate the source of these compounds.

Four metals were detected in the whole effluent in concentrations that exceeded the State chronic water quality criteria, but dilution zone modeling suggests that these should be reduced to well below criteria at the edge of the chronic dilution zone. Bioassays detected no effluent toxicity. Split samples results found significant differences between Ecology and Kettle Falls effluent samples, and it is recommended that Kettle Falls review sampling and holding procedures to ensure representative samples. A sludge sample collected from the bottom of the Kettle Falls south settling basin had high metal concentrations. Subsequent to the inspection (late 1995) Kettle Falls conducted a designation of a sludge sample under the provisions of the dangerous waste regulations indicating that it was not a dangerous waste and not subject to landfill disposal restrictions. Periodic monitoring of the sludge is recommended to ensure it does not pose a toxic hazard as a landfill leachate.