Enhanced degradation of Bisphenol A from high saline polycarbonate plant wastewater using wet air oxidation

Abstract

Abstract In the present study, wet air oxidation (WAO) was investigated for the decomposition of bisphenol A (BPA) in high saline polycarbonate plant wastewater (PCW). The main operating conditions of the WAO process that affects the degradation efficiency, including temperature, total air pressure and reaction time were studied. The results indicate that complete BPA degradation is achieved in pH 8.5, temperature = 150 °C, total air pressure of 3 MPa and 120 min. In addition, by prolonging the reaction time to 24 h, removals of 62% and 37%, were obtained regarding chemical oxygen demand (COD) and total oxygen carbon (TOC), respectively. The intermediates of BPA degradation generated in aqueous solution by the WAO process were identified and the proposed plausible mechanism was reported. Under optimum experimental conditions, the biodegradability of treated PCW after WAO process was shown to significantly improve, by analysis of biodegradability index, including BOD5/COD ratio, values of average oxidation state (AOS) and carbon oxidation state (COS). The WAO process was found to be an effective method to degrade highly toxic organic matter in high saline industrial wastewater such as PCW. The results indicate that WAO, as a pretreatment technology, is an economic and eco-friendly method for the treatment of PCW.