Enhanced pollutant removal in moving bed biofilm reactor under high-salinity condition via specialized quorum sensing...

The study aims to accelerate biofilm formation and operational performance of moving bed biofilm reactor (MBBR) in a high salt environment by adding specific quorum sensing (QS) strain (Vibrio sp. LV-Q1). Results showed that the addition of QS strain significantly promoted the pollutant removal process of the bioreactor. At the end of the reaction, the NH+ 4-N and COD removal rates of the bioaugmented MBBR (R1) were about 13.20 % and 10.15 % higher than the unbioaugmented MBBR (R0), respectively. The bioaugmentation of LV-Q1 enhanced the biofilm activity and adhesion of the system, which was related to the increase of polysaccharides and proteins in the biofilm. On day 70, the polysaccharides and proteins of the biofilm in R1 were increased by 41.66 % and 87.66 % compared with that in R0, respectively. And throughout the entire operation process, the biological system of R1 maintained a higher concentration of signal molecules, while the bioaugmentation of LV-Q1 made the biofilm distribution more uniform. Analysis of the microbial community structure further reflected that the strain Vibrio sp. LV-Q1 successfully proliferated (the relative abundance increased to 59.81 %). The bioaugmentation of exogenous addition of QS strain enhanced the expression of functional microorganisms and promoted the enrichment of Nitrincola, Marinobacterium, and Vibrio in the biofilm in a high salt environment. This work provides a new option for improving the MBBR for treating nitrogen-containing wastewater in a high salt environment.