Biofouling is inevitable in wastewater reclamation when using membrane technology. In particular, the extracellular polymeric substances (EPS) from biofilm is a major contributor to biofouling. Coagulation is critical in the process of reusing wastewater before membrane treatment, and residual coagulants (e.g., Al salts) are able to alter the characteristics of the biofilm EPS. However, the distribution of residual Al across varying biofilm EPS fractions and its effect on the membrane fouling potential resulting from biofilm EPS remains unclear. We found that 34% of the residual Al was present in the soluble EPS (S-EPS), 26% in the loosely bound EPS (LB-EPS) and 40% in the tightly bound EPS (TB-EPS). Moreover, compared with the control groups, the residual Al in biofilm induced more biofilm formation and more EPS formation. Al reduced the zeta potential and increased the hydrophobicity of the EPS. These changes induced a significant rise in the membrane fouling potential of S-EPS and LB-EPS. This work provides coagulation support for wastewater reclamation using membrane technology.

中文翻译：

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残余混凝剂Al对废水回收中生物膜EPS和膜污染潜力的影响

当使用膜技术时，在废水回收中不可避免地会产生生物污垢。特别是，来自生物膜的细胞外聚合物 (EPS) 是生物污垢的主要贡献者。在膜处理之前再利用废水的过程中，混凝是至关重要的，残留的混凝剂（例如铝盐）能够改变生物膜 EPS 的特性。然而，残留铝在不同生物膜 EPS 组分中的分布及其对由生物膜 EPS 引起的膜污染潜力的影响仍不清楚。我们发现 34% 的残留铝存在于可溶性 EPS (S-EPS) 中，26% 存在于松散结合的 EPS (LB-EPS) 中，40% 存在于紧密结合的 EPS (TB-EPS) 中。此外，与对照组相比，生物膜中残留的铝诱导更多的生物膜形成和更多的EPS形成。Al 降低了 zeta 电位并增加了 EPS 的疏水性。这些变化导致 S-EPS 和 LB-EPS 的膜污染潜力显着增加。这项工作为使用膜技术的废水回收提供了混凝支持。