Application of aerobic denitrifier for simultaneous removal of nitrogen, zinc, and bisphenol A from wastewater

High concentrations of heavy metals and other pollutants affect microbial activity in the wastewater treatment system and impede biological denitrification process. In this study, a novel Zn(II)-resistant aerobic denitrifier (Pseudomonas stutzeri KY-37) was isolated with potential in Bisphenol A (BPA) biodegradation and removal. The capability of this denitrifier in removing nitrogen, zinc, and BPA was tested. Using 56 mg/L nitrate as the sole nitrogen source, its removal efficiency achieved 98.5% in 12 h. This novel denitrifier had a strong auto-aggregation (maximum 65.8%), a high hydrophobicity rate (maximum 88.2%), and a massive amount (maximum 41.1 mg/g cell dry weight) of extracellular polymeric substances (EPS) production. Moreover, Zn(II) removal efficiency reached more than 95% with the initial high concentrations of 200 mg/L. The maximum BPA removal efficiency reached 88.8% with initial 10 mg/L. The removal mechanism of BPA was further explored in terms of microbial degradation, EPS adsorption, and intermediate degradation products.