以硝酸盐为主要氮源的反硝化除磷细菌驯化

以活性污泥为种泥,通过序批式反应器(Sequencing Batch Reactor,SBR),在厌氧-缺氧-好氧交替的条件下驯化培养以硝酸盐为主要氮源的反硝化除磷细菌(Denitrifying Phosphorus-Accumulating Organisms,DPAO)。在330 d的培养时间内监测磷酸盐、硝酸盐和亚硝酸盐等常规指标,并研究驯化不同阶段的一个周期内各指标的变化及进行相应的动力学分析。结果表明,随着驯化的进行,厌氧阶段释磷速率逐渐增加,释磷量也相应增大,出水磷质量浓度最终维持在0.8mg/L,去除率达到91.8%,硝氮全部去除。通过对16S r RNA测序结果的比对,得到聚磷菌占总菌的76.93%,反硝化除磷菌占聚磷菌的一半以上。而聚糖菌仅占5.13%,聚磷菌成为优势菌种。此外,在整个驯化过程中,水质和环境条件的变化使出水中磷质量浓度出现波动,而出水硝氮的变化不大。研究表明,以硝酸盐作为主要氮源培养反硝化除磷细菌的方式是可行的,并有利于聚磷菌对聚糖菌的竞争,使聚磷菌成为优势菌种。

Acclimation of denitrifying phosphorous-removing bacteria with nitrate as the main nitrogen source

The paper is aimed at introducing its research results on how to acclimate the phosphorus-accumulating organisms (DPAO) with nitrate as the main nitrogen source under the anaerobic,anoxic,and aerobic alternating conditions.We have done experiments by using the activated sludge collected from Dalian Ziguang Lingshui Sewage-Treating Plant as seedling and cultivated in a sequencing batch reactor (SBR).The experiment has lasted for 330 days and on the 60-th day,with nitrate supplied as the sole nitrogen source.And,then,it was on the 100-th day that we have found the denitrifying phosphorus removal process,which implies that the DPAO that we need has been acclimated successfully.In our experiments,we have also tested and measured the orthophosphate,nitrate,nitrite and other conventional indicators we have gained in the inflow and effluent and conducted the dynamic analysis of indicators in one cycle at different periods.The results have shown that with the acclimation of DPAO,both the phosphorus-release rate and quantity have increased gradually in the anaerobic phase.However,the effluent phosphorus has was remained below 0.8 mg/L in the final analysis with the phosphorus removal efficiency reaching 91.8％ with a complete consumption of nitrate.What is more,the dynamic analysis indicates that the anaerobic phosphate-release and anoxic/aerobic phosphateuptake tend to fit the first order of the kinetics equation.The results prove the PAO with the 16S rRNA gene sequence analysis considered to be the dominant bacteria in the SBR tend to account for 76.93％ of all the bacteria whereas the DPAO just takes over half of the PAO.As compared with the PAO,the glycogen-accumulating organisms (GAO) occupies only 5.13％ of all the bacteria.Besides,the DPAO cultured in the SBR proves to be sensitive for the change of the environment while the stability of phosphorus removal proves to be seriously influenced by the environmental factors,though the demystification process has always been stable during the whole experimental process.The experimental results have thus indicated that the approach to the acclimation of DPAO with nitrate as main nitrogen source turns to be feasible.And,the cultivation mode tends to be beneficial for the match of PAO to GAO,thus making PAO as the dominant bacteria.