Investigation of Nitrite Production Pathway in Integrated Partial Denitrification/Anammox Process via Isotope Labelling Technique and the Relevant Microbial Communities

In this study,the nitrogen removal performance of partial denitrificaiton/anammox(PDA)process was investigated by using an UASB reactor.High total nitrogen(TN)removal efficiency(91.97%)was achieved at an influent nitrogen loading rate of 0.64 kg/(m3·d).Anammox bacteria did execute the function of converting nitrate to nitrite in PDA system according to ^(15)N isotope labeling experiments and the contribution was approximately 36.3%.Candidatus_Brocadia,Candidatus_Kuenenia and Thauera were functional strains for anammox and denitrification process,respectively.Thauera and Candidatus_Brocadia were more important for TN removal at high loading rates(0.64 kg/(m3·d)).This result can provide a theoretical and technical foundation for the application of the PDA process.