Centre for Urban Environmental Remediation, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China; Beijing Energy Conservation & Sustainable Urban and Rural Development Provincial and Ministry Co-construction Collaboration Innovation Center, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.
Centre for Urban Environmental Remediation, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China; Beijing Energy Conservation & Sustainable Urban and Rural Development Provincial and Ministry Co-construction Collaboration Innovation Center, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.
Environ Res. 2022 Nov;214(Pt 2):114010. doi: 10.1016/j.envres.2022.114010. Epub 2022 Jul 31.
Low efficiency of anaerobic digestion and membrane fouling, treating landfill leachate, are big barriers in the application of anaerobic membrane bioreactor (AnMBR). Anaerobic digestion enhancement and membrane fouling mitigation of AnMBR with graphite addition, treating landfill leachate, were investigated in this study. The effect of graphite on organics removal, biogas production, methane content in biogas, membrane fouling, microbial responses and foulant compositions were analyzed. With the graphite addition, chemical oxygen demand (COD) removal of 78% was achieved for influent COD concentration of 3000 mg/l, which was significantly higher than the stage without graphite addition (65%) for influent COD concentration of 2000 mg/l. Similarly, methane content in biogas with graphite addition was 56%, while without graphite addition it was 46%. These digestion improvements were due to the promotion of organics degradation, facilitated by direct interspecies electron transfer (DIET) mechanism via graphite addition in AnMBR. The graphite addition prolonged membrane cleaning cycle from 13 days to 30 days. Protein content in loosely bound extracellular polymeric substance (LB-EPS) was the main fouling agent, which decreased with the graphite addition. The main mechanism behind membrane fouling mitigation was the protein content reduction in LB-EPS, which was biodegraded by Trichococcus being increased in relative abundance with the graphite addition. Furthermore, abundance of Denitratisoma decreased in anaerobic sludge and its accumulation reduced on membrane surface, subsequently membrane fouling was mitigated. Overall, graphite addition in AnMBR is a potential eco-innovative approach that efficiently removes pollutants from landfill leachate, enhances biogas quality and mitigates membrane fouling.
提高厌氧消化效率和缓解膜污染
本研究旨在探讨石墨强化厌氧膜生物反应器（AnMBR）处理垃圾渗滤液过程中，对其厌氧消化效率和膜污染的影响。分析了石墨对有机物去除、沼气产量、沼气中甲烷含量、膜污染、微生物响应和污垢成分的影响。
在石墨添加的情况下，对于进水 COD 浓度为 3000mg/L 的情况，COD 去除率达到 78%，而在没有石墨添加的情况下，进水 COD 浓度为 2000mg/L 时，COD 去除率仅为 65%。同样，添加石墨后沼气中的甲烷含量为 56%，而没有添加石墨时为 46%。这些消化改进是由于通过直接种间电子转移（DIET）机制促进有机物降解，从而提高了有机物的降解。
石墨的添加将膜清洗周期从 13 天延长到 30 天。松散结合胞外聚合物（LB-EPS）中的蛋白质含量是主要的污垢形成物质，随着石墨的添加，其含量减少。膜污染缓解的主要机制是 LB-EPS 中的蛋白质含量减少，由于相对丰度增加的 Trichococcus 对其进行生物降解。此外，厌氧污泥中 Denitratisoma 的丰度降低，其在膜表面的积累减少，从而缓解了膜污染。
总的来说，在 AnMBR 中添加石墨是一种有潜力的生态创新方法，可有效去除垃圾渗滤液中的污染物，提高沼气质量并缓解膜污染。
