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Effect of organic carbon on nitrogen conversion and microbial communities in the completely autotrophic nitrogen removal process

Jia, Li, Guo, Jin-song, Fang, Fang, Chen, You-peng, Zhang, Qiang
Environmental technology 2012 v.33 no.10 pp. 1141-1149
biofilm, carbon, carbon nitrogen ratio, chemical oxygen demand, denaturing gradient gel electrophoresis, denitrification, denitrifying microorganisms, environmental technology, microbial communities, nitrifying bacteria, nitrogen, nitrogen content, oxidants
Two identical SBBRs (sequencing batch biofilm reactors) were monitored to evaluate the effects of organic carbon (OC) on nitrogen conversion and microbial communities. In the organic-fed reactor, an ammonium conversion efficiency of above 99%, TN (total nitrogen) removal efficiency of 84–95% and COD (chemical oxygen demand) removal efficiency of about 90% were obtained at a C/N ratio of 1.2. In the OC-fed reactor, the contribution of partial nitrification–anammox to nitrogen removal decreased to 50.78%, and the contribution of denitrification increased to 49.22%. Denaturing gradient gel electrophoresis profiles showed an intensified bacterial diversity and an enrichment of Planctomycetes bacteria due to the presence of OC particularly in the biofilm. Clone library analysis revealed the coexistence of denitrifiers, aerobic ammonium oxidizers, and anammox bacteria in the OC-fed reactor.