Nitrogen removal characteristics of efficient heterotrophic nitrification-aerobic denitrification bacterium and application in biological deodorization

A heterotrophic nitrifying aerobic denitrifying (HN-AD) strain HY-1 with excellent capacity, identified as Paracoccus denitrificans, was isolated from activated sludge. HY-1 was capable of removing NH₄⁺, NO₂^-, and NO₃^- with the corresponding rate of 17.33 mg-N L^-1 h^-1, 21.83 mg-N L^-1 h^-1, and 32.37 mg-N L^-1 h^-1, as well as the mixture of multiple nitrogen sources. Meanwhile, HY-1 could execute denitrification function under anaerobic conditions with a rate of 14.56 mg-N L^-1 h^-1. HY-1 required less energy investment, which exhibited average denitrification rate of 5.19 mg-N L^-1 h^-1 at carbon-nitrogen ratio was 1. After nitrification-denitrification metabolic pathway analysis, HY-1 was applied in a biological trickling filter reactor for compost deodorization. The results showed that adding of HY-1 greatly reduced the ionic concentration of NH₄⁺ and NO₃^- in the circulating liquid without impairing the deodorization effect (NH₃ removal rate＞98.07%). These findings extend the field of application of HN-AD and provide new insights for biological deodorization.