title: Membrane fouling of forward osmosis (FO) membrane for municipal wastewater treatment: A comparison between direct FO and OMBR.
abstract: In this work, membrane fouling behavior in a direct forward osmosis (FO) and an osmotic membrane bioreactor (OMBR) for municipal wastewater treatment was systematically investigated and compared. During the long-term operation, much severer flux decline was observed for the direct FO than that for the OMBR. The cake layer was found to be much thicker, together with large amounts of microorganisms growing on the membrane surface in direct FO. Interestingly, no obvious attachment of microorganisms on the membrane surface was observed in the OMBR. The fourier transform infrared spectroscopy (FTIR) and excitation emission matrices (EEM) analyses showed the polysaccharides and proteins were the dominant organic foulants in the fouling layer, and the quantity of the organic substances was also higher in direct FO than that in OMBR. Energy-dispersive X-ray (EDX) results indicated the main inorganic elements in the fouling layer were Ca, Mg, Fe and P, all of which exhibited higher relative percentages in direct FO than that in OMBR. The occurrence of higher contents of microorganisms, organic foulants and inorganic elements in the cake layer caused a higher filtration resistance for the FO membrane in the direct FO. Although more severe membrane fouling was identified in direct FO, the hydraulic and chemical cleaning was more effective on recovering the water permeability of the membrane in direct FO than that in OMBR.
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors: Yan
authors: Y
authors: Sun
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: tjy800112@163.com.
authors: Jiayu
authors: J
authors: Tian
authors: Department of National Defense Construction Planning and Environmental Engineering, Logistical Engineering University, Chongqing 401311, China.
authors: Zhiwei
authors: Z
authors: Zhao
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors: Wenxin
authors: W
authors: Shi
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors: Dongmei
authors: D
authors: Liu
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: cuifuyi@hit.edu.cn.
authors: Fuyi
authors: F
authors: Cui
mesh_terms: D019149:Bioreactors; D008567:Membranes, Artificial; D009995:Osmosis; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification
chemical_list: D008567:Membranes, Artificial; D062065:Wastewater
keywords: Forward osmosis; Membrane fouling; Municipal wastewater; Osmotic membrane bioreactor