Smith Adam L, Skerlos Steven J, Raskin Lutgarde
Department of Civil and Environmental Engineering, University of Michigan, 2350 Hayward Road, Ann Arbor, MI, 48109, USA.
Department of Mechanical Engineering, University of Michigan, 2350 Hayward Road, Ann Arbor, MI, 48109, USA.
Microb Biotechnol. 2015 Sep;8(5):883-94. doi: 10.1111/1751-7915.12311. Epub 2015 Aug 4.
Membrane biofilm development was evaluated to improve psychrophilic (15°C) anaerobic membrane bioreactor (AnMBR) treatment of domestic wastewater. An AnMBR containing three replicate submerged membrane housings with separate permeate collection was operated at three levels of membrane fouling by independently controlling biogas sparging for each membrane unit. High membrane fouling significantly improved permeate quality, but resulted in dissolved methane in the permeate at a concentration two to three times the equilibrium concentration predicted by Henry's law. Illumina sequencing of 16S rRNA targeting Bacteria and Archaea and reverse transcription-quantitative polymerase chain reaction targeting the methyl coenzyme-M reductase (mcrA) gene in methanogens indicated that the membrane biofilm was enriched in highly active methanogens and syntrophic bacteria. Restoring fouled membranes to a transmembrane pressure (TMP) near zero by increasing biogas sparging did not disrupt the biofilm's treatment performance, suggesting that microbes in the foulant layer were tightly adhered and did not significantly contribute to TMP. Dissolved methane oversaturation persisted without high TMP, implying that methanogenesis in the biofilm, rather than high TMP, was the primary driving force in methane oversaturation. The results describe an attractive operational strategy to improve treatment performance in low-temperature AnMBR by supporting syntrophy and methanogenesis in the membrane biofilm through controlled membrane fouling.
为了改进嗜冷（15°C）厌氧膜生物反应器（AnMBR）处理生活污水的效果，对膜生物膜的形成进行了评估。一个包含三个重复的浸没式膜组件且具有独立渗透液收集装置的AnMBR，通过独立控制每个膜单元的沼气鼓泡，在三种膜污染水平下运行。高膜污染显著提高了渗透液质量，但导致渗透液中溶解甲烷的浓度比亨利定律预测的平衡浓度高出两到三倍。针对细菌和古菌的16S rRNA的Illumina测序以及针对产甲烷菌中甲基辅酶-M还原酶（mcrA）基因的逆转录定量聚合酶链反应表明，膜生物膜中富含高活性产甲烷菌和互营细菌。通过增加沼气鼓泡将污染膜恢复到接近零的跨膜压力（TMP），并未破坏生物膜的处理性能，这表明污垢层中的微生物紧密附着，对TMP的贡献不大。在没有高TMP的情况下，溶解甲烷过饱和现象持续存在，这意味着生物膜中的产甲烷作用而非高TMP是甲烷过饱和的主要驱动力。研究结果描述了一种有吸引力的操作策略，即通过控制膜污染来支持膜生物膜中的互营作用和产甲烷作用，从而提高低温AnMBR的处理性能。
