Comparison of ozonation and UV based oxidation as pre-treatment process for ultrafiltration in wastewater reuse: Simultaneous water risks reduction and membrane fouling mitigation. (April 2020)

• Record Type: Journal Article
• Authors: Li, Mo; Wen, Qinxue; Chen, Zhiqiang; Tang, Yingcai; Yang, Boxuan
• Is Part Of: Chemosphere. Volume 244(2020)
• Publication Date: 2020-04
• Subjects: Oxidation processes -- Ultrafiltration -- Membrane fouling -- Organic micro-pollutants -- Bio-toxicity; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.125449
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Wastewater reuse risk and membrane fouling are two concerns in ultrafiltration (UF) of secondary effluent (SE) for wastewater reuse. In this work, several wastewater reuse risk issues, such as dissolved effluent organic matters (dEfOM), organic micro-pollutants (OMPs) and bio-toxicity of SE, as well as membrane fouling were comprehensively investigated when ozonation, UV/H2 O2 and UV/persulfate (UV/PS) were used as the pre-treatments for UF process. To be specific, individual UF could remove DOC and UV254 by only 7.5% and 19.8%, respectively, however, humics were largely degraded during the pre-oxidation processes revealed by molecular weight and fluorescence analysis. UF and ozonation showed limited removal of OMPs, however, UV/H2 O2 and UV/PS dramatically degraded all the OMPs by more than 80%. Genotoxicity were not detected after the oxidation treatment. Membrane fouling may result from the collaborative effect of organic components, such as humic and protein like substances. Fourier transform infrared spectra of the fouled membranes showed that aromatic CC group and polysaccharides group in dEfOM were largely reduced after the oxidation pre-treatments, resulting in the improved membrane flux sustaining. Increased roughness of the membranes in the combined process supported that the less organics content after the oxidation pre-treatment contributed to improve the performance of the UF process. For the excellent organics degradation in UV/PS pre-treatment process, membrane fouling of subsequent UF process showed maximum mitigation. Highlights: Oxidation pre-treatments coupled with UF were used to reduce risks of reused water. OMPs and genotoxicity were effectively removed in the oxidation processes. Oxidation pre-treatment provide influent for UF with less dEfOM and mitigate fouling. Membrane fouling was resulted from synergistic effect of humics and proteins. UV/PS performed better in mitigating membrane fouling and organics removal.