Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore.
Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, 117576, Singapore; National University of Singapore Environmental Research Institute, 5A Engineering Drive 1, 117411, Singapore.
Water Res. 2020 Jul 15;179:115850. doi: 10.1016/j.watres.2020.115850. Epub 2020 Apr 26.
Quorum quenching (QQ) has been applied as a promising membrane fouling control strategy for anaerobic membrane bioreactors (AnMBRs). Nevertheless, long-term operation of AnMBRs for real domestic wastewater (DWW) treatment needs to be systematically studied to evaluate comprehensive membrane fouling mechanisms and bioprocess performance. In this study, the impact of QQ on membrane fouling was investigated using a quorum quenching AnMBR (QQAnMBR) deploying a bead-entrapped facultative quorum quenching consortium (FQQ) to treat DWW. FQQ was shown to prolong membrane filtration operation by an average of 75%. Reduced proteins (p < 0.005) and carbohydrates (p < 0.005) in the extracellular polymeric substances (EPS) of mixed liquor (ML) were key differentiators that led to lower cake layer (CL) formation. Additionally, reduced biopolymers production (p < 0.05) in EPS improved sludge dewaterability. The findings suggested that QQ could alter fluorescent microbial metabolites of both EPS and CL as unveiled by excitation-emission matrix spectra pattern. Furthermore, colloidal particles (i.e., particles with size larger than 0.45 μm in ML supernatants) production was retarded by QQ, thereafter, also contributed to the reduced CL formation. Pore blockage was slightly increased by QQ, which might be attributed to pore blockage by large (∼230 nm) and small organic compounds (∼51 nm) in soluble microbial products (SMP). However, QQ had no significant impact on organic concentration of SMP, and QQ was not associated with particle size distribution of biomass. QQ performance was further affirmed through suppressed production of C4-HSL, 3-OXO-C6-HSL, and C6-HSL. The overall AHLs degradability of FQQ was well-maintained even after five membrane service cycles (total operation of 70 d). Moreover, QQ had no compromised impact on treatment performance (i.e., chemical oxygen demand (COD) removal and methane yield). Collectively, this study bridged the knowledge gap to bring forward QQ technology in AnMBR for widespread domestic wastewater treatment application.
群体感应淬灭 (QQ) 已被应用于厌氧膜生物反应器 (AnMBR) 作为一种有前途的膜污染控制策略。然而，为了评估全面的膜污染机制和生物处理性能，需要对 AnMBR 长期处理实际生活污水 (DWW) 的情况进行系统研究。在这项研究中，使用一种群体感应淬灭厌氧膜生物反应器 (QQAnMBR) 来处理 DWW，该反应器中使用了一种珠状固定化兼性群体感应淬灭生物群落 (FQQ)，研究了 QQ 对膜污染的影响。结果表明，FQQ 将膜过滤操作的平均延长了 75%。混合液 (ML) 中胞外聚合物 (EPS) 中的蛋白质 (p<0.005) 和碳水化合物 (p<0.005) 减少是导致滤饼层 (CL) 形成减少的关键区别因素。此外，EPS 中生物聚合物产量的减少 (p<0.05) 改善了污泥的脱水性能。研究结果表明，QQ 可以改变 EPS 和 CL 中荧光微生物代谢物的组成，这可以通过激发-发射矩阵光谱模式揭示。此外，胶体颗粒 (即 ML 上清液中粒径大于 0.45μm 的颗粒) 的产生被 QQ 延迟，从而减少 CL 的形成。QQ 略微增加了孔堵塞，这可能是由于可溶微生物产物 (SMP) 中较大 (约 230nm) 和较小的有机化合物 (约 51nm) 引起的。然而，QQ 对 SMP 的有机浓度没有显著影响，并且 QQ 与生物量的颗粒尺寸分布无关。通过抑制 C4-HSL、3-OXO-C6-HSL 和 C6-HSL 的产生，进一步证实了 QQ 的性能。即使经过五个膜使用周期 (总运行 70d)，FQQ 对 AHLs 的整体降解能力也得到了很好的维持。此外，QQ 对处理性能 (即化学需氧量 (COD) 去除率和甲烷产率) 没有不利影响。总的来说，这项研究填补了知识空白，将 QQ 技术引入 AnMBR 中，以广泛应用于生活污水处理。
