Applicability of a novel osmotic membrane bioreactor using a specific draw solution in wastewater treatment

This study aims to develop a new osmotic membrane bioreactor by combining a moving bed biofilm reactor (MBBR) with forward osmosis membrane bioreactor (FOMBR) to treat wastewater. Ethylenediaminetetraacetic acid disodium salt coupled with polyethylene glycol tert-octylphenyl ether was used as an innovative draw solution in this membrane hybrid system (MBBR-OsMBR) for minimizing the reverse salt flux and maintaining a healthy environment for the microorganism community. The results showed that the hybrid system achieved a stablewater flux of 6.94 L/m(2) h and lowsalt accumulation in the bioreactor for 68 days of operation. At a filling rate of 40% (by volume of the bioreactor) of the polyethylene balls used as carriers, NH4+-N and PO43--P were almost removed (> 99%) while producing relatively low NO3--N and NO2--N in the effluent (e.g. < 0.56 and 0.96 mg/L, respectively). Furthermore, from analysis based on scanning electron microscopy, Fourier transform infrared spectroscopy, and fluorescence emission-excitation matrix spectrophotometry, there was a thin gel-like fouling layer on the FOmembrane, which composed of bacteria as well as biopolymers and protein-like substances. Nonetheless, the formation of these fouling layers of the FO membrane inMBBR-OsMBR was reversible and removed by a physical cleaning technique. (C) 2015 Elsevier B.V. All rights reserved.