低C/N比城市污水短程硝化特性及微生物种群分布

Characteristics and microbial populations distribution of shortcut nitrification with low C/N ratio urban sewage

以城市污水厂二沉池回流液为接种污泥,研究了低C/N城市污水短程硝化特性及其微生物种群密度分布规律,并对比研究了SBR和SBBR 2种反应器短程硝化特性的差异。结果表明:在温度(30±1)℃、pH=7.9~8.2、DO=1.0 mg·L^(-1)的条件下,通过分段曝气的运行方式、经过29 d的运行,2个反应器均实现了短程硝化的高效启动,NH_4^+-N转化率稳定在99%,短程硝化率稳定在90%以上;相比于SBR,SBBR更有利于AOB菌种的富集,且SBBR达到亚硝酸盐积累率最大效果的时间快于SBR。利用聚合酶链反应(PCR)和克隆测序等分子生物学技术分析得出,在短程硝化稳定运行的SBR系统中,AOB菌种与NOB菌种的占比为2.3∶1。

The inoculated sludge for the study was collected from the secondary sedimentation tank of a municipal wastewater treatment plant. The characteristics and microbial population distribution of shortcut nitrification for urban wastewater with low C / N were researched. Meanwhile,the difference between the nitrifying properties of the SBR and SBBR reactors was discussed. The results showed that after 29 days of operation at a temperature of（ 30 ± 1） ℃,pH of 7. 9 to 8. 2 and DO of 1. 0 mg·L^-1,shortcut nitrification can be achieved efficiently and stably with the rates of ammonia removal and nitrite production being above 99% and 90%,respectively. Compared to SBR,the conditions in SBBR were favorable for the growth of ammonium oxidizing bacteria（ AOB）,which resulted in the enhancement of the rate of nitrite accumulation. From the results of the polymerase chain reaction（ PCR）,the ratio of AOB and nitrite oxidizing bacteria（ NOB） was 2. 3 ∶ 1 in a stable operation SBR system with shortcut nitrification.