Publication Summary

An unannounced Class II inspection was conducted at the Boise Cascade (Wallula) pulp and paper mill October 21-23, 1996. Tier 2 permit limits based on mill production were in effect at the time of the inspection. Results showed Boise Cascade′s ASB effluent and final effluent were within discharge limits for BOD5, TSS, and pH. Fecal coliform counts in the final effluent were low.

An unannounced Class II inspection was conducted at the Boise Cascade (Wallula) pulp and paper mill October 21-23, 1996. Tier 2 permit limits based on mill production were in effect at the time of the inspection. Results showed Boise Cascade′s ASB effluent and final effluent were within discharge limits for BOD5, TSS, and pH. Fecal coliform counts in the final effluent were low.

Split sample results showed that Ecology analyses for BOD5 were in agreement with Boise Cascade analyses. There were no consistent trends in the differences between TSS results. Variations in results between Ecology and Boise Cascade analyses for ASB effluent and final effluent TSS can be attributed largely to the nonhomogenous nature of paper mill effluent. Boise Cascade sample results compared closely with results from Ecology samples for primary influent, primary effluent, aerated stabilization basin (ASB) influent, and ASB effluent. The Boise Cascade final effluent sample yielded BOD5 and TSS results considerably higher than the Ecology sample results, and it is recommended that Boise Cascade sampling procedures for final effluent be evaluated.

Removal efficiencies across the primary clarifier were 10% for BOD5 and 83% for TSS. Removal efficiency for BOD5 across the ASB was 90%. TSS concentrations increased across the ASB. This increase can be attributed to the production of microorganisms in the ASB and their incomplete settling.

Of the seven priority pollutant metals found in the final effluent sample, none were found in a concentration exceeding chronic or acute state fresh water criteria at the dilution zone boundaries. The ASB influent sample was analyzed for both total metals and total recoverable metals so that a comparison could be made. Variability in results between metals analyses for the same sample obscured any consistent differences between total metals and total recoverable metals analysis methodologies. Of the pesticide/PCB analyses for primary and ASB influent and effluent, PCB-1260 (Aroclor-1260) was found at an estimated concentration of 0.090 mg/L in the primary influent. No other pesticide/PCBs were found.