青铜峡灌区典型排水沟水污特征解析

以2009年青铜峡灌区排水沟实测流量和污染物浓度为基础,结合典型排水沟纳污现状调查及灌区灌溉与排水特点,对比点源污染和非点源污染的浓度和负荷特征,对典型排水沟污染物来源进行解析.结果表明,青铜峡灌区典型排水沟农田排水期盐分、氨氮、总磷月平均浓度依次为1 124、8.59、0.48 mg.L-1,非农田排水期盐分、氨氮、总磷月平均浓度分别为1 952、18.13、4.15 mg.L-1,农田排水期月平均输出盐分、氨氮、总磷负荷为20 896、90.35、5.80 t,非农田排水期月平均输出盐分、氨氮、总磷负荷分别为7 842、67.81、21.38 t.其中,第一排水沟水污过程与农田灌溉排水周期具有很好的一致性,表明第一排水沟以农田灌溉排水和农业非点源污染为主;第三排水沟、银新沟等则在承接农田灌溉排水的基础上,接纳了较多的点源污染,表现出点源与非点源综合污染并以点源污染为主导的污染特征.

Source Characteristics Analysis of Discharge and Pollutants in Typical Drainage Ditch of Qingtongxia Irrigation District

Based on the discharge and pollutants of drainage ditch in Qingtongxia Irrigation District at the Yellow River upstream in 2009. Source characteristics of discharge and pollutants in typical drainage ditch were analyzed by combined pollution survey of typical drainage ditch and characteristics of irrigation and drainage in Qingtongxia Irrigation District. Comparative analysis the pollution characteristics of point source pollution and non-point source pollution. The results showed, the monthly mean concentration of salinity, ammonia nitrogen, total phosphorus was 1124, 8.59, 0.48mg·L^-1,the monthly mean load was 20896, 90.35, 5.80 t, respectively in farmland drainage period. The monthly mean concentration of salinity, ammonia nitrogen, total phosphorus was 1952, 18.13, 4.15mg·L^-1, the monthly mean load was 7842, 67.81, 21.38 t in non-farmland drainage period. Meanwhile, the drainage and pollutants in Diyi drainage ditch is mainly composed of irrigation drainage and agricultural non-point source pollution, and the process of drainage and pollutants has a good correspondence with farmland irrigation interval. In contrary, Disan drainage ditch and Yinxin drainage ditch etc, due to irrigation drainage and agricultural non-point source pollutants was drained into,and a large amount of sewage above the standards was drain into, too, the drainage and pollutants showed comprehensive pollution characteristics of point source pollution and agricultural non-point source pollution, which point source pollution was the dominant factors.