Treatment of organically contaminated groundwaters in municipal activated sludge systems

Abstract

ABSTRACT: A pilot‐scale treatability study was performed to evaluate the capability to effectively co‐treat pumped groundwaters from industrial sites with municipal wastewaters at publicly owned treatment works (POTWs) employing activated sludge treatment. Chemicals given focused attention included selected phenolic, polycyclic aromatic hydrocarbon (PAH), and volatile aromatic compounds. The study involved the simultaneous operation of three pilot‐scale activated sludge reactors. One reactor was fed 100% municipal wastewater (control), a second was fed a 5% by flow volume site groundwater with a relatively low organic concentration, and a third was fed a 20% by flow volume site groundwater with a higher organic concentration. Monitoring was carried out to address, through reactor mass balance computations, chemical fate in terms of activated sludge adsorption, biodegradation, volatilization, and effluent discharge quality. The results of this study support the co‐treatment of contaminated groundwaters in POTWs employing activated sludge systems. The results show nonmeasurable effects in terms of activated sludge treatment performance, and nonsignificant effects in terms of treated effluent discharge and waste activated sludge quality. This work can be used to aid engineers and POTW authorities in evaluating the capability of activated sludge treatment systems to effectively handle and treat groundwaters containing phenolic, PAH, and volatile aromatic compounds.