Modeling Bioaugmentation Potential for Enhanced Bisphenol A Removal During Wastewater Treatment

Pharmaceutical and personal care products (PPCPs) discharged with wastewater treatment plant effluents are documented contaminants in many surface waters with potential ecological impacts at extremely low concentrations (ng/L range). PPCPs are partially removed during wastewater treatment. Biological transformation is an important removal mechanism and, bacteria have previously been isolated from activated sludge capable of degrading PPCPs to ng/L concentrations. This study investigated the potential application of these bacteria for enhanced PPCP removal through bioaugmentation into activated sludge processes. Bisphenol A, an endocrine disrupting compound (EDC) was used as a model contaminant. Comparison of models developed for three reactor configurations (continuous mixed activated sludge, CMAS; continuously stirred tank reactors (CSTR) in series; and sequencing batch reactors, SBR) demonstrated that extremely low residual contaminant concentrations could be achieved in both the effluent and waste activated sludge (WAS) with less than 10% increases to the volatile suspended solids (VSS). Additionally, sorption modeling predicted that both liquid and solid-associated contaminants were removed. When the bacteria were added to activated sludge, degradation increased. These results demonstrated that the tested bioaugmentation process may be a viable new technology for improved PPCP removal at wastewater treatment plants.