Enrichment of nitrifying bacterial in sequencing batch reactors

In this study, sequencing batch reactors (SBRs) were used to enrich for dense cultures of nitrifying bacteria. The cultivation conditions of nitrifying bacteria in activated sludge systems will directly affect the nitrogen and other nutrients removal efficiency and the efficient and stable operation of the system. Therefore, take SBRs as the carrier, by cultivating the activated sludge, which were taken from the secondary settling pond of a sewage treatment plant, the number of the heterotrophic bacteria in the sludge decrease while that of the nitrobacteria which become the predominant bacteria increase. The result showed that the enrichment of nitrifying bacteria is feasible under the appropriate pH, temperature, DO and other conditions, and the system of NH₄⁺-N removal rate of more than 98%, nitrification rate improved 3 times than that before enrichment.