Packed Tower Air Stripping – An Economical Alternative for Meeting California's Stringent THM Limits

Abstract

Facing stringent wastewater discharge limits for trihalomethanes (THMs), the City of Turlock has investigated treatment alternatives for reducing THM concentrations of discharges from the City of Turlock Water Quality Control Facility (WQCF). The WQCF currently uses chlorine disinfection and THMs are byproducts of chlorine disinfection processes. THMs are regulated because they are classified as a human health risk for drinking water services. WWTPs in California facing similar limits typically replace their chlorine disinfection process with UV disinfection; however, UV disinfection facilities have significantly higher capital and operating costs.An alternative to replacing the existing chlorine disinfection system is to remove the THMs from the chlorinated effluent. Packed tower air stripping may be a technically viable option for doing so. The City tested a pilot packed tower air stripper at the WQCF and initial results indicate packed tower air stripping may be an economical alternative to meeting their upcoming THM limits.