低温条件下微生物对沉积物氮释放的影响研究

Microbial effects on sediments nitrogen release in low water temperature

通过室内静态模拟实验，研究了沉积物中氮的释放特性。将反应器密封后自然达到厌氧状态，温度与水库底部相近（7～8℃），进行未灭菌和灭菌两个系列对比试验，连续监测两个系列装置中NO3^-N、NO^2-N、NH4^＋-N、TN、DO和pH的变化，并对试验前后沉积物中的总氮含量进行测定。结果表明，未灭菌装置沉积物中总氮减少量明显多于灭菌装置，而上覆水中可监测总氮少于灭菌装置，说明在厌氧条件下氮元素会在微生物作用下从沉积物中释放出来，并通过反硝化和厌氧氨氧化等作用以气态形式释放出水体。试验前后对底泥表面的硝化、亚硝化、反硝化和氨化细菌的数量通过计数进行了比较，发现厌氧后反硝化细菌和氨化细菌明显增多，说明厌氧过程中对氮释放起主要作用的是反硝化细菌和氨化细菌。

The release characteristics of nitrogen from reservoir sediments were investigated through static simulation experiment in laboratory. The reactor was sealed to keep anaerobic naturally, the water temperature was similar with bottom of the reservoir（7 - 8 ℃）. Experiments with sterilized and non-sterilized sediment were conducted for continuous measurement of NO3^- - N, NO2^- - N, NH4^＋ - N, TN, DO and pH. The result showed that nitrogen released from non-sterilized sediments was more than one of the sterilized, but it was contrary in the upper water. It indicated that in an anaerobic condition, nitrogen would be released from sediments with a process of microorganism, and the nitrogen was converted into gaseous and was escaped from water with denitrification and anaerobic ammonia oxidation. The bacteria number of nitrification, nitrosation, denitrification and ammonifying were compared before and after anaerobic process, it was found that bacteria of denitrification and ammonifying were increased evidently after anaerobic process. It indicated that bacteria of denitrification and ammonifying played a major role in the process of nitrogen release from the sediments.