Publication Summary

A Class II Inspection was conducted at the Aluminum Company of America Wenatchee Works (ALCOA) December 1-3, 1992. The sanitary sewage treatment plant (STP) was performing well during the inspection. The STP effluent met permit limits for BOD5, TSS, fecal coliform, and pH. The 001 discharge (stormwater, non-contact cooling water, and sanitary effluent) was also well within NPDES permit limits. Few organic pollutants were detected in either the STP effluent or the combined 001 outfall.

A Class II Inspection was conducted at the Aluminum Company of America Wenatchee Works (ALCOA) on December 1-3, 1992. The sanitary sewage treatment plant (STP) was performing well during the inspection. The STP effluent met permit limits for BOD5, TSS, fecal coliform, and pH. The 001 discharge (stormwater, non-contact cooling water, and sanitary effluent) was also well within NPDES permit limits. Few organic pollutants were detected in either the STP effluent or the combined 001 outfall.

With the exception of acetone, used for laboratory cleaning, all VOA and BNA organic compounds found were in concentrations less than 10 mg/L. Two PAHs were found in the 001 effluent at estimated concentrations of 0.03 mg/L or below. Of the five priority pollutant metals found in the 001 effluent, lead (in one of four samples) and cadmium exceeded EPA chronic freshwater water quality criteria and zinc exceeded acute and chronic criteria. Bioassays for Daphnia magna, Ceriodaphnia dubia, fathead minnow, and rainbow trout showed no adverse effects. The need for a review of ALCOA STP influent sampling; TSS, fluoride, and aluminum analysis; and mercury and nickel sampling and analysis are indicated.