微生物在水体自净中的作用:以清潩河为例

为了研究微生物在水体自净中发挥的作用,采用降解系数来表征水体对COD、NH₃-N、TN和TP的自净能力,使用氯化汞灭活微生物作为对照组,将降解系数分为综合降解与生物降解。在清潩河3个特征河段进行原位降解系数测算实验,并选取典型河段进行微生物高通量检测。结果表明:1)河道内微生物主要类群为小梨形菌属、热单胞杆菌属等常见的专性好氧菌属和少量的能够进行硝化作用的菌属。2)COD、NH₃-N的生物降解系数与其综合降解系数呈正相关,且生物降解起主要作用,占比分别为76%和48%,TN和TP则无显著相关性,说明COD和NH₃-N较于TN和TP更依赖于河道的生物自净作用。3)将生物降解系数与综合降解系数拟合,结合一级动力学降解方程,推导出生物降解、综合降解后浓度和初始浓度之间的数量关系式。

FUNCTION OF MICROORGANISMS IN WATER PURIFICATION:A CASE STUDY OF THE QING-YI RIVER

The self-purification of water bodies is of great significance in the study of water environment. Microorganisms are the main bearers of self-purification of water bodies. In order to study the role of microorganisms in self-purification of water bodies, this study used degradation coefficients to characterize the self-purification of water bodies to COD, ammonia nitrogen, TN and TP. To use mercury chloride inactivated microorganisms as a control group, the degradation coefficient was divided into comprehensive degradation and biological degradation. In-situ degradation coefficient calculation experiments were carried out in three characteristic sections of the Qing-Yi River, and typical sections were selected for high-throughput microbial detection. The results showed that: 1) the main groups of microorganisms in the river were the common obligate aerobic genus such as Pyricularia sp., Thermomonas sp, and a small number of genus bacteria capable of nitrification. 2) The biodegradation coefficients of COD and ammonia nitrogen were positively correlated with their comprehensive degradation coefficients, and the proportion of biodegradation was high, 78% and 42%, respectively. TN and TP had no significant relationship, indicating that COD and ammonia nitrogen were more dependent on biological self-purification than TN and TP in the river channel. 3) Through fitting the biodegradation coefficient with the comprehensive degradation coefficient, and combining the first-order kinetic degradation equation, the equation between the initial concentration and the concentration after comprehensive degradation and biological degradation was deduced.