常温低基质亚硝化反应器功能菌群解析

Analysis of the functional bacteria community in partial nitrification reactor for low strength sewage treatment at ambient temperature

摘要:

为维持亚硝化反应器稳定运行提供微生物理论基础，以常温（18~21.5℃）低基质推流式亚硝化反应器为对象，解析其稳定运行期间功能菌群特征.通过检测反应器三氮变化检验其亚硝化效果.利用扫描电镜（SEM）观察污泥微观结构，通过荧光原位杂交（FISH）、变性梯度凝胶电泳技术（DGGE）及克隆测序等方法，解析微生物菌群特性.保持反应器低溶解氧环境（0.1~0.6 mg/L），使氨氧化菌（AOB）竞争力强于亚硝酸盐氧化菌（NOB），在连续流运行80 d内，平均亚硝化率几乎为100%，出水NO₂^--N与NH₄⁺-N质量比稳定在1.11.SEM结果显示，亚硝化污泥中球形细菌为优势菌群.FISH结果显示，AOB与NOB的相对比例分别为37.3%与4.4%.PCR-DGGE结果表明，反应器内存在6类优势微生物菌群，其中Nitrosomonas sp.为功能微生物AOB.由多种微生物组成的功能菌群维持反应器亚硝化稳定运行.

Abstract:

Partial nitrification (PN) process was successfully developed in a plug flow reactor fed with low strength sewage at ambient temperature (18-21.5℃). For better detecting the efficiency and mechanism of the partial nitrification process in the PN reactor, ammonia, nitrite, and nitrate were detected firstly, subsequentially the functional bacterial community in the reactor was also investigated at microbial level. The sludge microstructures were detected by scanning electron microscopy (SEM), and the microbial characteristics was studied via fluorescence in situ hybridization (FISH), denaturing gradient gel electrophoresis (DGGE), cloning and sequencing analyzing. The DO concentration was maintained between 0.1 to 0.6 mg/L, to enhance AOB competition superiority. After 80 days continuous operation, PN reactor achieved nitrite accumulation rate of 100% and effluent NO₂^--N to NH₄⁺ -N ratio achieved 1.11. SEM results showed that spherical bacteria were the predominant bacteria in partial nitrifying sludge. FISH results showed the proportion of AOB and NOB were 37.3% and 4.4%, respectively. Bacterial DGGE and sequencing results indicated that six dominant bacteria coexisting in the PN reactor, among which Nitrosomonas sp. were the main AOB species.Those multiple functional bacteria contributed to the nitrogen removal in PN reactor.