对BAF预处理低温水源水系统中硝化细菌的识别

Identification of nitrifying bacteria in biological aerated filter in pretreatment of polluted raw water at low temperature

生物处理工艺是解决水源水氨氮污染问题的主要途径,但其功能菌属硝化细菌在工艺系统中受诸多因素影响,尤其在低温期生物活性下降,因此识别适应低温水环境的硝化细菌,有利于为其构筑最适生长环境,进而提升工艺降解氨氮的效果。以前期构建的悬浮填料-沸石曝气生物滤池为基础,研究了经长期低温驯化后,适应低温水环境的菌种及其演替。研究表明,对曝气生物滤池系统中的硝化细菌按属、种进行分类,主要的氨氧化细菌菌属是Nitrosomonas,优势菌种为Nitrosomonas uncultured ammonia-oxidizing bacterium。就亚硝酸盐氧化细菌而言,主要的菌属为Nitrospiraceae Nitrospira和Candidatus Nitrotoga,其中Nitrospiraceae Nitrospira为硝化系统中常见菌属,Candidatus Nitrotoga是新型的、可以功能性替代Nitrospira的菌属,更适在低温环境下生长;进一步将硝化细菌按种进行分类发现,系统中亚硝酸盐氧化细菌的优势菌种为Nitrospiraunculturedbacterium、Nitrospira uncultured soil bacterium、Nitrospira sp.、Candidatus Nitrospira defluvii和Candidatus Nitrotoga uncultured bacterium。

The biological treatment process is the main way to solve the problem ot ammoma nitrogen pollution in water sources, but the functional bacteria are affected by many factors in the system, especially by low temperature. Therefore, the identification of nitrifying bacteria suitable for low temperature water environment would help to build the optimal conditions, and then im- prove the process＇ ability to remove ammonia nitrogen. Based on a previously constructed suspen- ded media-zeolite biological aerated filter, the nitrifying bacteria species acclimated to low tempera ture water environment and their succession were studied, after long-term acclimation under low temperature. The results showed that the major ammonia-oxidizing bacteria was Nitrosomonas,and the dominant species was Nitrosomonas uncultured ammonia-oxidizing bacterium. The major nitrite oxidizing bacteria were Nitrospira and Candidatus Nrotrotoga. Nitrospira is a common ni- trite oxidizing bacteria in engineered systems, while Candidatus Nrotrotoga is a new species which can functionally replace Nitrospira and is more adaptive to low temperature environment. Further classification of the nitrifying bacteria revealed that the dominant nitrite oxidizing bacteria species were Nitrospira uncultured bacterium, Nitrospira uncultured soil bacterium, Nitrospira sp. , CandidatusNitrospira de fluvii and Candidatus Nitrotoga uncultured bacterium.