地下水硝酸盐污染生物修复中的亚硝态氮积累研究

EXPERIMENT RESEARCH ON THE PROBLEM OF NITRITE ACCUMULATION IN GROUNDWATER DURING BIOLOGICAL DENITRIFICATION

针对地下水硝酸盐污染生物修复过程中出现的亚硝态氮积累问题,试验分析在以硝酸盐和亚硝酸盐为主要电子受体的两个体系中,硝酸盐氮和亚硝酸盐氮的去除速率以及磷源对二者的影响,从而探究硝酸盐生物修复过程中亚硝态氮积累的因素。结果表明:在碳源不足的情况下,硝酸盐还原菌对碳源的竞争能力强于亚硝酸盐还原菌,此时将会出现亚硝酸盐的积累。碳源充足时,亚硝酸盐为主要电子受体的体系中亚硝酸盐氮的还原速率约为以硝酸盐为主要电子受体的体系中硝酸盐氮还原速率的1.7倍。磷浓度也是影响反硝化过程中亚硝酸盐积累的重要原因。在其他条件不变的情况下,添加磷源后,硝酸盐为主要电子受体的体系中硝酸盐氮的还原速率约为未添加时的1.16倍;亚硝酸盐为主要电子受体的体系中亚硝酸盐氮的还原速率约为未添加时的1.23倍。

For the problem of the accumulation of nitrite during the biological repair process of the groundwater contaminated by nitrate, the removal rate of NO3^-N and NO2^-N and the affect of phosphate-P on both of them in the two systems whose electron acceptor are nitrate and nitrite respectively, were analyed, thus factors of the accumulation of nitrite during biological denitrification could be researched. The results showed that for the carbon source, nitrate-reducing bacteria was more competitive than nitrite-reducing bacteria when carbon sources was insufficient, and the nitrite would be accumulated. The denitrification rate in the system whose main electron acceptor is nitrite was 1.7 times as high as that of nitrate. And phosphate-P concentration was another important factor affecting the nitrite accumulation. In the system whose main electron acceptor was nitrate, when the phospbate-P was added, the denitrification rate was about 1.16 times as high as that of the system with no hosphate-P added, assuming that other conditions remained unchanged; and the multiple was 1.23 times when the main electron acceptor was nitrite.