IMPACT OF A HIGH SULFATE AND TDS INDUSTRIAL DISCHARGE ON MUNICIPAL WASTEWATER TREATMENT

Beginning in late 1996, an industrial wastewater discharge high in total dissolved solids (TDS) and sulfate increased the levels of TDS and sulfate in the municipal wastewater treatment plant and the receiving stream. Levels up to 1900 mg/L of TDS and 1100 mg/L of sulfate had no impact on the biological treatment units used for nitrification or anaerobic sludge digestion or the biotic integrity of the aquatic life in the receiving stream. The elevated levels of TDS and sulfate did increase anaerobic digester gas hydrogen sulfide levels from less than 100 ppm (V) to over 5000 ppm (V) and produced a white sulfur containing deposit in the gas handling system. Proposed increases in the industrial discharge of TDS and sulfate up to 2650 mg/L and 1350 mg/L, respectively, were evaluated. No impacts were predicted on the biological treatment units used for nitrification or the indigenous fish in the receiving stream at those concentrations. Hydrogen sulfide scrubbing of the anaerobic digester gas is planned for the proposed increase in sulfide concentrations.