地下水硝酸盐去除中反硝化微生物的研究进展

地下水硝酸盐污染已经成为一个全球问题,由于饮用高硝酸盐含量的地下水会增加高铁血红蛋白症和癌症风险,地下水硝酸盐污染受到越来越多的关注。反硝化脱氮是地下水硝酸盐脱氮的主要途径之一。本文就参与地下水硝酸盐去除的反硝化微生物种类、反硝化机理、碳源类型以及地下水污染中微生物作用的国内外研究现状进行了较全面系统的评述。在此基础上,提出了该类研究中存在的不足,包括实验室研究较多但野外研究较少,野外原位应用中对特定微生物特性方面研究缺乏,碳源利用率低和硝酸盐去除速度慢,去除过程中有效微生物的代谢途径仍不清楚等问题。针对这些问题,本文认为以后的研究应该进一步开发野外原位应用中反硝化微生物资源,并借助先进的分子方法和功能基因鉴定此类特殊微生物的种类、功能及其生态学行为,选择最佳碳源,完整深入地了解地下水硝酸盐去除中微生物的代谢过程,识别反硝化过程中氮的来源与去向,为寻找提高处理效率的方法提供理论依据,真正将理论和实践结合起来。

Research review of denitrifying microorganisms of groundwater to nitrate denitrification

There has been an increasing global trend in nitrate contamination of groundwater, and especially in China. This has raised concern for increased nitrate-caused methemoglobinemia and cancer. Available technical data and experience have indicated that denitrification was a more acceptable method for nitrate removal than reverse osmosis and ion exchange. This paper systematically reviewed the denitrifying micro-organisms, denitrification mechanisms, carbon sources, and laboratory/field-scale nitrate removal processes for effective denitrification of groundwater. Key problems with previous studies were also pointed out. As the reviewed showed that there were more related laboratory research than field research, information on the characteristics of specific micro-organisms involved in on-site nitrate removal from groundwater was limited. In addition, the utilization ratio of carbon sources was low and nitrate removal rate from groundwater was also slow. Despite the above issues, metabolic pathways of effective denitrifying micro-organisms used in nitrate removal from groundwater were still unclear. Hence the proposed relevant suggestions included: 1) In situ exploitation of denitrifying micro-organisms. Identification of the specific functions and ecological behaviors of micro-organisms via advanced molecular methods and function gene analyses. 2) Selection of the best sources of carbon and metabolic processes of microorganisms during nitrate removal from groundwater. 3) Clarification of the denitrification processes of nitrogen transformation in groundwater. All the above suggestions provided the basis of the theory of nitrite removal from groundwater, making both the theory and practice more reliable combination.