Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Research Center for Environmental and Hazardous Substance Management (EHSM), Department of Environmental Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen, 40002, Thailand.
Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA.
Chemosphere. 2021 Aug;277:130284. doi: 10.1016/j.chemosphere.2021.130284. Epub 2021 Mar 13.
Membrane fouling by dissolved organic matter (DOM), especially microbially-derived DOM, is a major challenge for ultrafiltration (UF) membranes in water purification. Fouling may be mitigated by pretreating feed waters; however, there are no comprehensive studies that compare the fouling reduction efficacies across different pretreatment processes. Further, there is a limited understanding of the relationship between fouling reduction efficacy and microbially-derived DOM removal from source waters. Accordingly, the objectives of this study were to: (i) evaluate and compare the efficacies of five pretreatment processes in reducing UF membrane fouling by DOM; and (ii) investigate whether a relationship exists between membrane fouling reduction and microbially-derived DOM removal by pretreatment processes. We investigated seven water sources and a polyvinylidene fluoride hollow-fiber UF membrane using bench-scale fouling tests. Dissolved organic carbon content, ultraviolet absorbance and fluorescence excitation-emission matrix spectroscopy were used to assess DOM concentration and composition. Alum and ferric chloride coagulation were the most effective pretreatment processes in reducing membrane fouling, anion exchange was moderately effective, and PAC adsorption and chlorine pre-oxidation were the least effective. Consistent with previous studies, microbially-derived DOM was the major contributor to UF membrane fouling regardless of water source or pretreatment type. Fouling reduction was strongly correlated with the reduction of microbially-derived DOM in foulant layers but not from source waters. This result indicates that a fraction of the total microbially-derived DOM in feed waters was responsible for UF fouling. Overall, pretreatment processes that remove microbially-derived DOM are well-suited for UF membrane fouling reduction.
溶解性有机物（DOM），尤其是微生物来源的 DOM，对水净化中超滤（UF）膜的污染是一个主要挑战。通过预处理进水可以减轻污染，但目前还没有全面的研究比较不同预处理工艺的污染减轻效果。此外，对于污染减轻效果与从原水中去除微生物来源的 DOM 之间的关系，我们的理解也很有限。因此，本研究的目的是：（i）评估和比较五种预处理工艺在降低 DOM 引起的 UF 膜污染方面的效果；（ii）研究预处理过程中膜污染减轻与微生物来源 DOM 去除之间是否存在关系。我们使用中试规模的污染试验，考察了七种水源和一种聚偏氟乙烯中空纤维 UF 膜。采用溶解性有机碳含量、紫外吸光度和荧光激发-发射矩阵光谱法评估 DOM 的浓度和组成。铝盐和铁盐混凝是降低膜污染最有效的预处理工艺，阴离子交换适度有效，而 PAC 吸附和预氯化氧化效果最差。与先前的研究一致，无论水源或预处理类型如何，微生物来源的 DOM 都是 UF 膜污染的主要贡献者。污染减轻与污染物层中微生物来源 DOM 的减少密切相关，但与原水中的去除无关。这一结果表明，进水中总微生物来源 DOM 的一部分是 UF 污染的原因。总的来说，去除微生物来源 DOM 的预处理工艺非常适合用于 UF 膜污染减轻。
