城市污泥中氮磷在壤土和砂土中的淋溶实验研究

Leaching experiment of nitrogen and phosphorus in municipal sludge in loam and sand soil

研究探讨了壤土和砂土上施用城市污泥对地下水中氮和磷的影响。以北京市高碑店污水处理厂的生污泥和庞各庄堆肥厂的堆肥作为土壤施加的污泥源,采用自制土柱淋溶模型的方法研究壤土和砂土上施用不同污泥量时灌水对土柱中pH、氮、磷的淋出情况,测定分析淋滤液中的pH值、总氮和总磷。实验设计4种处理,分别为污泥施用量占土壤干重的0(不施污泥,对照处理)、2%、4%和6%。实验结果表明:淋滤液的pH值显著变低;总氮和总磷以波动方式逐渐降低,并随淋洗次数的增多逐渐低于空白对照水平,而且壤土和砂土中淋滤液的变化规律不同。污泥添加2%时淋滤液氮磷含量最低,堆肥添加4%时淋滤液氮磷含量最低。污泥施用到壤土和砂土上,适量时不会造成地下水氮磷的污染,同时有益于土壤养分的保持,减少养分流失。

In order to analyze the effects of urban sewage sludge applied in sand and loam soil on nitrogen（N） and phosphorus（P） in groundwater,a gradient test design was conducted with 4 treatments of 0（control）,2%,4%,6%（rates of sludge application expressed as sludge to soil ration）.Different quantity of sewage sludge selected from Beijing Gaobeidian Wastewater Treatment Plant and the compost of Panggezhuang Composting Plant were added in the sand and loam and the soil column models were used to study the release process of pH,N and P under the condition of irrigation after measuring the value of pH,total N（TN） and total P（TP） in the leachate.The results showed that the pH value was significantly reduced.TP and TN decreased in the way of wave pattern and lower than CK with the increasing number of leaching,and the variation regularity of leachate in the sand was different from that in loam.The contents of N and P decreased to the lowest level when the sewage sludge and compost were added 2% and 4% respectively.The right amount of sludge applied in the loam and sand will not cause the pollution of N and P in the groundwater,and it is beneficial to keeping soil nutrient.