Investigation of denitrification to Anammox phase transformation performance of Up-Flow anaerobic sludge blanket reactor

For investigating the microbial community and nitrogen removal performance during the transformation from heterotrophic denitrification (HtDn), mixotrophic denitrification (MtDn), and autotrophic denitrification (AtDn) to anaerobic ammonia oxidation (Anammox), an up-flow anaerobic sludge blanket reactor was constructed by changing the influent substrates and their ratios. The reactor got a total nitrogen removal efficiency (TNRE) of 98.0 % at the molar ratio of carbon, nitrogen, and sulfur sources was 5:8:4 in the MtDn process. In the last phase, the conversion of AtDn to Anammox was successful in 33 days, and a stable TNRE was 87.7 %. The dominant functional bacteria of the microbial communities were Thauera and unclassified_Comamonadaceae in the HtDn process; Thiobacillus, Thauera, Denitratisoma, and Pseudoxanthomonas in the MtDn process; Thiobacillus and Sulfurimonas in the AtDn process; and unclassified_Gemmatimonadaceae, unclassified_SBR1031, and Candidatus_Brocadia in the Anammox process.