Removal of Selected Pharmaceuticals and Personal Care Products from Wastewater using Soybean Peroxidase

Personal care products and pharmaceuticals have been reported in various concentrations in the effluent of municipal sewage treatment plants (STP). Although they are generally found in the nanogram to microgram per liter range, many of them might have adverse health effects on humans at these concentrations. Conventional treatments applied at the STP are unable to effectively remove most of these recalcitrant compounds, thus there is a necessity for development of alternative treatment techniques. In this article, the efficiency of enzymatic treatment using soybean peroxidase in treating some commonly found micropollutants is discussed. The target compounds were, two phenolic surfactant breakdown products, nonylphenol and octylphenol, two antimicrobial agents, Triclosan and sulfamethoxazole and three phenolic steroids. The effects of the most important parameters pH, enzyme concentration and peroxide concentration have been evaluated for each compound. The treatment of synthetic wastewater was shown to be effective (≥95% removal), except for sulfamethoxazole, in concentration ranges of 10 s of µM at neutral pH with 2-5 mU/L of catalytic activity and 2-3 molar equivalents of hydrogen peroxide. The effectiveness of the treatment has also been determined for lower concentrations (6-9 nM) which approximate those in real wastewater. A matrix effect was found in the treatment of Triclosan in spiked real wastewater indicating that re-optimization of important parameters for STP treatment would be required to achieve high removal efficiency. A reverse-phase, solid-phase extraction technique was used to concentrate target analytes in real wastewater, enabling chromatographic detection by UV absorbance.