LAUSR

Bioaugmentation of extracellular polymeric substances-producing bacteria was applied in pollutant removal and S0 recovery from composite wastewater in a mixotrophic denitrification system. In the presence of 200 mg·L-1 S2- and 50 mg·L-1 Cr(VI), the removal efficiencies of chemical oxygen demand, NO3-, S2- and Cr(VI) were 86.38%, 91.82%, 95.75%, and 100.00% respectively, while S0 recovery efficiency reached 79.17%. Increased contents of protein and polysaccharide, especially the high ratio of protein/polysaccharide verified the structural stability of biofilm was promoted by biofilm enhancement. The widespread distribution of bacteria/EPS revealed the more obvious biofilms formation in biofilm-enhanced group. High-throughput sequencing analysis showed that EPS-producing bacteria (Flavobacterium, Thauera, Thiobacillus and Simplicispira) were dominant bacteria in the biofilm-enhanced group. Moreover, by comprehensive considering of redundancy analysis, the colonization of selected bacteria improved the robustness of the reactor and treatment performance to wastewater contained toxic pollutions.