Development of Local Limits for Sulfate Discharged to a Municipal Wastewater Treatment Plant

This paper provides an evaluation of the potential impact of sulfate in wastewater discharged to the City of Camas, WA sewer system on the operation and performance of the City's sewer system and Wastewater Treatment Facility (WWTF), and identifies potential mitigation measures. Specifically, this paper presents an evaluation of the impact of high concentrations of sulfate and total dissolved solids (TDS) on the settling of sludge in the City's secondary clarifiers, the potential for inhibition of, and other negative impacts on, the City's anaerobic digester system currently under construction, and other negative impacts on the operation of the Camas WWTF and collection system. Maximum allowable headworks loadings are calculated for sulfate and TDS, for the purpose of local limits development, based on the findings of this evaluation.