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Stable and efficient partial nitritation granular sludge reactor treating domestic sewage at low temperature
- Zhang, Jianhua, Zhang, Qiong, Miao, Yuanyuan, Sun, Yawen, Chen, Jianfei, Peng, Yongzhen
- Bioresource technology 2018 v.270 pp. 746-750
- ammonium, anaerobic ammonium oxidation, bacteria, dissolved oxygen, municipal wastewater, nitrites, oxidation, phosphorus, sewage, sludge, temperature
- The success of combined partial nitritation (PN) and anammox process treating low-strength domestic wastewater depends on achieving a stable and efficient PN. In this study, desirable PN for domestic sewage with low temperature of 11.8–16.9 °C was achieved in a granular sludge reactor operated in anaerobic/aerobic (A/O) mode. Average nitrite accumulation ratio of 97.3% was obtained with an effluent nitrite/ammonium ratio of 1.2 for influent ammonium of 39.3–78.7 mg·L−1. Quantitative microbial analysis and activity batch test showed that nitrite oxidizing bacteria (NOB) were effectively suppressed, while ammonium oxidizing bacteria (AOB) were dominant. For the efficient suppression of NOB, A/O mode, aerobic phosphorus uptake and granular sludge could play important roles. Furthermore, high AOB activity was obtained with an average ammonium oxidation rate of 11.6 mg N·L−1·h−1, which could be due to the abundant psychrotolerant microorganisms, increased content of extracellular polymeric substances and relatively high dissolved oxygen condition of the reactor.