城市污水灌溉中氮素转化的实验研究及污染风险分析

污水灌溉是我国北方地区城市郊区农业发展的既 成事实.它一方面可以缓解当地的农业水资源紧缺的 矛盾，另一方面，污水中还含有作物生长所必需的丰富 的氮、磷、钾等营养元素.但是由于缺乏科学指导，用于 灌溉的污水大多数未经任何处理，污水中含有的有毒 有害物质已经使污水灌

Experimental study on nitrogen transformation in municipal wastewater irrigation system and analysis of its contamination risk

The experimental study objects are the wastewater and soil of Xiqing District in Tianjin. By studying on the movement and transformation of NH3 -N and the change of NO3 - -N concentration, the contamination risk of nitrogen in wastewater irrigation is analyzed. Two factors may result in the gradual accumulation of NO3 -N in the soil. One is the eluvi-ation of NO3- and NO2 - in the soil by wastewater irrigation. The other is the entering of NO3 - and NO2- , which are produced through the nitrification of high concentration nitrous organic matters and NH4 + in the wastewater, into the underwater, and further into the lower layers with wastewater irrigation. Significance should, therefore, be attached to the risky accumulation of NO3- in the underwater.