Effect of pyrite/sulfur ratio on nitrogen removal in autotrophic denitrification dynamic membrane bioreactor

Abstract

Abstract In this study, pyrite and sulfur were used as electron donors to form a pyrite/sulfur autotrophic dynamic membrane bioreactor (SP-DMBR). The effect of pyrite/sulfur (P/S) ratio on pollutant removal and membrane pollution was studied. Our findings showed that 3 was optimal P/S ratio for SP-DMBR. The NH4+-N, COD, and NO3−-N removal efficiencies were 93.81%, 95.85%, and 90.27% respectively, and the NO2−-N accumulation was 0.46 mg/L. However, the production of SO42− was significantly reduced, and the pH was stable at 7.3–7.8. At this ratio, the transmembrane pressure (TMP) increases steadily. Microorganisms associated with nitrogen and sulfur cycle mainly belongs to the Desulfuromusa, Desulillus, Denitratisoma, Ellin6067, Desulfuromusa, Thauera, Desulitalea, Prolixibacteraceae and Caldithrix genera. P/S ratio affected the denitrifying microorganism species and the abundance of desulphurizing microorganisms. Linear discriminant analysis (LDA) was used to investigate the significant differences in microbial community structure.