College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China.
College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai, 200090, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, Jiangsu, PR China.
Water Res. 2019 May 15;155:310-319. doi: 10.1016/j.watres.2019.02.039. Epub 2019 Feb 26.
The sludge in situ reduction process by inserting an anaerobic side-stream reactor (ASSR) in a sludge return line provides a cost-effective approach to reduce sludge production in activated sludge systems. In this study, four pilot-scale membrane bioreactors (MBRs), including an AO-MBR for control, ASSR coupled MBR (ASSR-MBR), a MBR with ASSR packed with carriers (AP-MBR) and an AP-MBR with part of sludge ultrasonicated before fed into ASSR (AUP-MBR) were operated in parallel to investigate enhancing effects of ultrasonication and packing carriers on sludge reduction and pollutants removal performance under both normal and low temperature. Low temperature showed negligible impact on COD removal, deteriorated NHN and TN removal from 98.3% to 69.7% at 21.6 °C to 92.5% and 48.8% at 2.6 °C, and decreased sludge reduction efficiency (SRE) in ASSR-MBR. Packing carriers and ultrasonication both enhanced sludge reduction, especially under low temperature with SRE values increased from 8.2% of ASSR-MBR to 17.1% of AP-MBR and 32.6% of AUP-MBR at 4.5 ± 2.5 °C. Packing carriers and ultrasonication increased cell rupture by 11.1% and 14.5% in aerobic MBR, enhanced protease activity in ASSR by 60.0% and 116.3%, and reduced ATP content for heterotrophic metabolism by 31.4% and 7.3%, respectively. MiSeq sequencing results showed that packing carriers enriched hydrolytic bacteria (Terrimonas, Dechloromonas and Woodsholea), slow growers (Sulfuritalea, Thauera and Azospira) and predatory bacteria (Bdellovibrio and norank_Saprospiraceae), while ultrasonication further enriched hydrolytic bacteria (norank_Saccharibacteria and Ferruginibacter). Packing carriers is more cost-effective than ultrasonication to enhance sludge reduction by partial damage to bacterial cells and promoting better interaction between bacteria, enzymes and substrates to favor particles hydrolysis.
在污泥回流管中插入厌氧侧流反应器 (ASSR) 的污泥原位还原工艺为减少活性污泥系统中的污泥产量提供了一种具有成本效益的方法。在这项研究中，四个中试规模的膜生物反应器 (MBR)，包括一个用于对照的 AO-MBR、ASSR 耦合 MBR (ASSR-MBR)、ASSR 填充载体的 MBR (AP-MBR) 和部分污泥在进入 ASSR 之前进行超声处理的 AP-MBR (AUP-MBR) 被平行运行，以研究超声处理和填充载体在正常和低温条件下对污泥减少和污染物去除性能的增强效果。低温对 COD 去除几乎没有影响，但在 21.6°C 时，NHN 和 TN 的去除率从 98.3%恶化至 69.7%，在 2.6°C 时，去除率从 92.5%和 48.8%恶化至 69.7%，ASSR-MBR 的污泥减少效率也降低。填充载体和超声处理都增强了污泥减少，尤其是在低温条件下，ASSR-MBR 的污泥减少效率从 8.2%提高到 AP-MBR 的 17.1%和 AUP-MBR 的 32.6%。填充载体和超声处理分别使好氧 MBR 中的细胞破裂增加了 11.1%和 14.5%，ASSR 中的蛋白酶活性分别增加了 60.0%和 116.3%，异养代谢的 ATP 含量分别减少了 31.4%和 7.3%。MiSeq 测序结果表明，填充载体富集了水解细菌（Terrimonas、Dechloromonas 和 Woodsholea）、缓慢生长菌（Sulfuritalea、Thauera 和 Azospira）和捕食细菌（Bdellovibrio 和 norank_Saprospiraceae），而超声处理进一步富集了水解细菌（norank_Saccharibacteria 和 Ferruginibacter）。与超声处理相比，填充载体通过对细菌细胞的部分损伤来增强污泥减少，并且促进细菌、酶和底物之间更好的相互作用，从而有利于颗粒水解，更具成本效益。
