Reducing ultrafiltration membrane fouling during potable water reuse using pre-ozonation

WATER RESEARCH

卷:125

Article

Wang, Hui¹  Park, Minkyu²  Liang, Heng¹  Wu, Shimin²  Lopez, Israel J.²  Ji, Weikang²  Li, Guibai¹  Snyder, Shane A.^2,3 

[1] Harbin Inst Technol, SKLUWRE, 73 Huanghe Rd, Harbin 150090, Heilongjiang, Peoples R China

[2] Univ Arizona, Dept Chem & Environm Engn, Tucson, AZ 85721 USA

[3] Natl Univ Singapore, Environm Res Inst, T Lab Bldg 02-01,5A Engn Dr 1, Singapore 117411, Singapore

关键词: Potable reuse;    Membrane fouling;    Ultrafiltration;    Ozonation;    Effluent organic matter;   

DOI  :  10.1016/j.watres.2017.08.030

来源: Elsevier

【 摘 要 】

Wastewater reclamation has increasingly become popular to secure potable water supply. Low-pressure membrane processes such as microfiltration (MF) and ultrafiltration (UF) play imperative roles as a barrier of macromolecules for such purpose, but are often limited by membrane fouling. Effluent organic matter (EfOM), including biopolymers and particulates, in secondary wastewater effluents have been known to be major foulants in low-pressure membrane processes. Hence, the primary aim of this study was to investigate the effects of pre-ozonation as a pre-treatment for UF on the membrane fouling caused by EfOM in secondary wastewater effluents for hydrophilic regenerated cellulose (RC) and hydrophobic polyethersulfone (PES) UF membranes. It was found that greater fouling reduction was achieved by pre-ozonation for the hydrophilic RC membrane than the hydrophobic PES membrane at increasing ozone doses. In addition, the physicochemical property changes of EfOM, including biopolymer fractions, by pre-ozonation were systemically investigated. The classical pore blocking model and the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theories were employed to scrutinize the fouling alleviation mechanism by pre-ozonation. As a result, the overarching mechanisms of fouling reduction were attributed to the following key reasons: (1) Ozone degraded macromolecules such as biopolymers like proteins and polysaccharides into smaller fractions, thereby increasing free energy of cohesion of EfOM and rendering them more hydrophilic and stable; (2) pre-ozonation augmented the interfacial free energy of adhesion between foulants and the RC/PES membranes, leading to the increase of repulsions and/or the decrease of attractions; and (3) pre-ozonation prolonged the transition from pore blocking to cake filtration that was a dominant fouling mechanism, thereby reducing fouling. (C) 2017 Elsevier Ltd. All rights reserved.

【 授权许可】

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