Comparison of the Microbial Community Structure in Different Anaerobic Ammonia Oxidation Denitrification Systems by High-throughput Sequencing

Two different reactor types, an anaerobic sequencing batch reactor (ASBR) and a biofilter reactor, were inoculated with sludge from the second settling tank of a wastewater treatment plant in Guangzhou, China. To explore the differences between the two reactors, during the start-up period, influent water at pH 7.5 ± 0.1 was applied. The results showed that the ASBR reactor could successfully start up after 134 days, while the biofilter could start up after 114 days. In both systems, total nitrogen removal was 80% after more than 200 days of operation. The diversity of denitrifying microorganisms was high in both reactors with Planctomycetes which are the main taxa. The anammox bacteria in the ASBR included Candidatus anammoxoglobus and Candidatus kuenenia, while in the biofilter reactor, we also detected Candidatus brocadia, albeit at a low concentration. In summary, biofilter could start up faster than ASBR, and contains richer species, which makes it more suitable to domesticate anammox bacteria.