水库底泥氮释放及其好氧微生物脱氮研究

Abstract

以丹江口水库为例,考察水库底泥在不同温度、扰动和曝气等条件下,总氮、硝氮、氨氮和亚硝氮的释放规律。设置模拟反应器,探究高效好氧脱氮微生物强化消除水库底泥内源氮污染的效果,并运用高通量测序技术,分析高效好氧脱氮微生物对底泥微生物群落结构的影响。结果表明,温度升高会减少氨氮的释放,增加硝氮和亚硝氮的积累;水体扰动会加速底泥中氮素释放,且上覆水中的氮素释放累积量与扰动速度成正比;溶解氧对底泥氮素释放有显著影响,曝气处理可以明显地降低底泥中总氮和硝氮的释放及其在水体中的累积。在反应器中底泥–上覆水界面投加高效好氧脱氮微生物Pseudomonas stutzeri (PCN-1)后,反应器内各种形态的氮素都出现先上升、后下降的趋势;在反应器运行的第65天,底泥释放的总氮和硝氮的去除率分别高达75.87%和79.96%,底泥内源氮污染得到有效的控制。对比投加菌株前后的微生物群落结构,发现底泥中Proteobacteria,Bacteroidetes和Spirochaetes的相对丰度明显增加,PCN-1强化脱氮处理能够改变底泥的微生物群落结构。

This study focuses on the Danjiangkou reservoir, and investigates the release regulation of total nitrogen, nitrate, nitrite and ammonia from sediments as a function of temperature, perturbation and aeration conditions. Moreover, a simulation reactor was set up to explore the elimination of endogenous nitrogen pollution through high-efficient aerobic denitrification microorganism augmentation. Effects of high-efficient aerobic denitrification microorganisms on the microbial community structure in the sediments was also evaluated by means of high-throughput sequencing technology. The results indicated that increasing temperature could promote the release of nitrate and nitrite from sediments, while inhibiting the release of ammonium. Disturbances of water was beneficial to nitrogen release from sediments, and the nitrogen amount accumulated in the overlying water was proportional to the agitation speed. Concentrations of dissolved oxygen had great effects on the nitrogen release from sediments. It was found that the aeration treatment significantly reduced the release of total nitrogen and nitrite from sediments, and the subsequent accumulation in water. After addition of the a high-efficient aerobic denitrification bacteria Pseudomonas stutzeri(PCN-1) into the simulation reactor, concentrations of all the forms of nitrogen in the reactor increased at first and then decreased. On the 65 th day of the experiment, removal rates of total nitrogen and nitrate released from sediments were as high as 75.87% and 79.96% respectively, suggesting effective control of the endogenous nitrogen. The relative abundance of Proteobacteria, Bacteroidetes and Spirochaetes in sediments was significantly increased after PCN-1 addition, so the microbial community structure in the sediments was changed by microbial augmentation treatment with PCN-1 as well.