Process Safety and Environmental Protection, Vol.140, 111-123, 2020
Advanced oxidation technologies combined with direct contact membrane distillation for treatment of secondary municipal wastewater
In this work, the combination of advanced oxidation technologies (AOTs) and direct contact membrane distillation (DCMD) was investigated for the treatment of municipal wastewater collected from the sec-ondary clarifier of a municipal wastewater treatment plant (MWWTP). Average removal efficiencies of the 12 micropollutants present in the wastewater samples were higher than 95 % with ozonation (O-3) and photolytic ozonation (UV/O-3), whereas only near 50 % of removal efficiency was achieved with UV-peroxidation (UV/H2O2). When the ozone-based processes were combined with DCMD, the concen-tration of these micropollutants were below the detection limits in the respective permeate, increasing the quality of the treated water. However, the permeate fluxes in DCMD were remarkably higher when the wastewater was pre-treated with UV/H2O2 instead of O-3, most probably due to the better disinfection achieved by UV/H2O2. It was also confirmed that the dissolved organic carbon (DOC) of the wastewater strongly affects the permeate fluxes achieved by DCMD. In this regard, the combination of the oxida-tion and membrane separation processes is more appropriate for wastewaters with low DOC contents (< 15 mg L-1). (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.