Feasibility of ultrafiltration-based processes for simultaneous removal of trace-level ofloxacin and sulfamethazine from the effluent of WWTPs

Abstract

The emergence of emerging contaminants, especially antibiotics, poses a great challenge to the traditional treatment processes in wastewater treatment plants (WWTPs) due to their non-biodegradable and toxic properties. In this study, the potential of UF-based processes for concurrently removing trace-amount (ng/L-μg/L) ofloxacin (OFC) and sulfamethazine (SMT) from the real effluent of WWTPs was assessed. The operational conditions of single UF were firstly optimized including molecular weight cut-off (50 kDa) and filtration pressure (25 kPa) with the maximum OFC and SMT retention of 60.65 ± 1.61 % and 50.21 ± 2.11 %, respectively. The impacts of dissolved organic matter (DOM) and NO3− on UF for the concurrent abatement of antibiotics were explored. It was noteworthy that DOM (below 25 mg/L) could enhance OFC abatement by UF, whereas NO3− was adverse for the concurrent abatement of OFC and SMT. The optimal combining sequence of UF and O3 processes for concurrently removing OFC and SMT from the effluent of WWTPs was also investigated. Compared with O3-UF, UF-O3 demonstrated a higher efficiency for concurrent elimination of OFC and SMT. The tech-economic feasibility analysis indicated that UF-O3 could provide one promising option for simultaneously removing OFC and SMT from the WWTPs effluent due to its relatively low potential ecological risks based on UV254 removal, acute toxicity and three-dimensional fluorescence spectroscopy (3D-EEM) and excellent cost-effectiveness (the operating cost is about 0.35 CNY/m3).