Microbial community composition of a lab-scale submerged MBR

Membrane fouling is a major problem to the widespread application of membrane technologies. In this study, the microbial community composition in a MBR was characterised over time using high-throughput sequencing. In addition, the efficacy of nitric oxide (NO) for reducing transmembrane pressure (TMP) and microbial community changes was investigated. Sequence analysis revealed Bacteroidetes (average at 51%) and Proteobacteria (average at 31.4%) were the most abundant organisms present. There was a strong correlation between the significant reduction in the relative abundance of Saprospiraceae (10.3%) and unclassified TM7-3 (6.7%) in the sludge samples at the time when the TMP began to increase dramatically. Backwashing of the membranes with the NO donor, DETA NONOate, led to a reduction of the TMP by 35% compared to 21% obtained by the control (P-value < 0.05), demonstrating that DETA NONOate effectively reduced biofouling as shown by the improvement in TMP.