Reactor configuration on the nitrifier community and kinetics of activated sludge process

摘要

Both a nitrifying sequencing batch reactor (SBR) and a completely stirred tank reactor (CSTR) were operated under aerobic conditions. Microbial populations of both reactors were examined via fluorescent in situ hybridization (FISH) and kinetic properties such as ammoniumitrite utilization rate and half-saturation constants (K-S) were investigated. In the SBR, dominant ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were rapid growth r-strategists (Nitrosomonas europaea and Nitrobacter). However, in the CSTR, the dominant AOB and NOB were slow growth K-strategists (Nitrosospira and Nitrospira). The half-saturation constants of AOB and NOB were 3.01 +/- 0.97 and 4.22 +/- 0.64 mg/L, respectively, for the SBR and 0.43 +/- 0.19 and 2.15 +/- 0.64 mg/L, respectively, for the CSTR. The nitrification rate of the SBR was 63% higher than that in the CSTR. The reactor configuration shows an evident selectivity for K/r-strategists. Thus, the difference in nitrification rates between the SBR and CSTR are likely caused by the combination of chemical reaction engineering kinetics and nitrifier communities.