光照、流速和水温对大型人工输水渠道自净影响

以南水北调中线总干渠为对象，通过实验室模拟培养测定污染物降解系数，分析了光照、流速和温度对渠道自净能力的影响.结果显示，避光和光照条件下，高锰酸盐指数的降解系数分别为0.026和0.022d^-1，无显著性差异（P>0.05）；氨氮的降解系数分别为0.006和0.012d^-1，差异极显著（P<0.01）.各流速条件下高锰酸盐指数降解系数分别为0.027d^-1（0.2m/s）、0.029d^-1（0.3m/s）、0.029d^-1（0.4m/s），氨氮降解系数分别为0.014d^-1（0.2m/s）、0.017d^-1（0.3m/s）、0.018d^-1（0.4m/s），不同流速之间无显著性差异，但均显著高于0m/s实验组（P<0.05）.各温度条件下高锰酸盐指数降解系数分别为0.014d^-1（10℃）、0.018d^-1（15℃）、0.022d^-1（20℃）、0.029d^-1（25℃）和0.031d^-1（30℃），25~30℃差异不显著（P>0.05），其他各温度梯度之间均存在显著性差异；氨氮降解系数分别为0.002d^-1（10℃）、0.003d^-1（15℃）、0.010d^-1（20℃）、0.012d^-1（25℃）和0.020d^-1（30℃），10~15℃、15~20℃和20~25℃差异不显著，其他温度梯度之间均具有显著差异.高锰酸盐指数和氨氮的温度校正系数θ值分别为1.047和1.079.研究结果可为中线工程水质管理提供依据.

Influence of light,flow rate and water temperature on self-purification of large artificial water conveyance channels

Taking the main channel of the middle route of the South-to-North Water Diversion Project as the object, the degradation coefficients were measured through laboratory culture experiments, and the effects of light, flow rate and temperature on the self-purification capacity of the channel were analyzed. The results showed that the degradation coefficients of permanganate index under dark and light were 0.026d^-1 and 0.022d^-1, respectively, with no significant difference (P>0.05). The degradation coefficients of ammonia nitrogen under dark and light were 0.006d^-1 and 0.012d^-1, respectively, and the difference was extremely significant (P<0.01). Under different flow rates, the degradation coefficients of permanganate index were 0.027d^-1 (0.2m/s), 0.029d^-1 (0.3m/s), 0.029d^-1 (0.4m/s), and the degradation coefficients of ammonia nitrogen were 0.014d^-1 (0.2m/s), 0.017d^-1 (0.3m/s), 0.018d^-1 (0.4m/s), respectively. There was no significant difference between different flow rates, but they were significantly higher than the 0m/s group. Under different temperatures, the degradation coefficients of permanganate index were 0.014d^-1 (10℃), 0.018d^-1 (15℃), 0.022d^-1 (20℃), 0.029d^-1 (25℃) and 0.031d^-1 (30℃), respectively. There was no significant difference between 25℃ and 30℃ (P>0.05), and there were significant differences among other temperatures. The degradation coefficients of ammonia nitrogen were 0.002d^-1 (10℃), 0.003d^-1 (15℃), 0.010d^-1 (20℃), 0.012d^-1 (25℃) and 0.020d^-1 (30℃), respectively. There were no significant differences for 10~15℃, 15~20℃ and 20~25℃, and there were significant differences for other temperature gradients. The temperature correction factor θ of permanganate index and ammonia nitrogen were 1.047 and 1.079, respectively. The research results could provide a basis for water quality management of the middle route of the South-to-North Water Diversion Project.