Membrane bioreactor and advanced oxidation processes for combined treatment of synthetic wastewater containing naproxen, bisphenol A, and sulfamethoxazole

Abstract

Environmental and health issues caused by the abundance of emerging pollutants in the aquatic environment motivate the research into wastewater treatment methods. In the present study, a membrane bioreactor (MBR) and advanced oxidation processes (AOPs) were combined for the efficient treatment of a synthetic wastewater containing naproxen (NPX), bisphenol A (BPA), and sulfamethoxazole (SMX). The MBR setup consisted of a sequencing batch reactor (SBR) linked to an external filtration system. Track-etch membranes (TEM) with pore size of 10 nm, 50 nm, and 100 nm and a phase inversion membrane (PIM) were used. The total organic carbon (TOC) removal for the SBR was in the range of 78–86 %, while the degradation of NPX, BPA, and SMX observed was 11 %, 45 %, and 6 %, respectively. All of the four membranes tested showed insignificant TOC removal efficiencies ranging from 1 % to 6 %. In the case of emerging pollutants, the highest removal values were observed for the 10 nm TEM: 11 %, 93 %, and 14 % for NPX, BPA, and SMX, respectively. The removal of BPA using membranes was possibly linked to sorption and size exclusion. Finally, the effluents from SBR and MBR were treated using UV-driven AOPs. Persulfate (PS) was used as an oxidant, and UV light, zero-valent iron (ZVI), goethite, and iron (II) sulfate heptahydrate were used as activators. Complete mineralization of TOC and removal of emerging pollutants were achieved after 30 min for MBR effluents using UV/PS 10 mM /ZVI 25 mg/L, which shows the high potential of using MBR and AOPs in combination.