污泥堆肥施用对土壤及地下水影响研究

Effects of sludge composting products on soil and groundwater

为探究北京市污泥堆肥产品施用对土壤和地下水的影响,采用原状土柱模拟降雨试验方法,研究了在污泥堆肥产品年施用量为3、6、12kg/m^2的条件下,Cu、Cr、Ni、Zn、Pb、Cd、As、Hg 8种重金属元素的迁移和淋溶特征.结果表明,Cd淋溶后残留最少(6.1%~11.9%),进入淋溶水最多(4.5%~7.3%);Hg淋溶残留最多(16.0%~22.1%),进入淋溶水最少(<0.1%).Hg、Pb、Ni、Cd、Cu在0~20cm土壤层积累最多(52.0%~78.7%);Cr、Zn、As则在20~40cm层积累最多(42.7%~53.2%).8种元素在土壤中的含量均符合《土壤环境质量农用地土壤污染风险管控标准(试行)》(GB 15618-2018)限值.淋溶水中测得的6种重金属浓度由大至小依次为Zn>As>Cd>Cu>Pb>Cr,受堆肥施用量及降雨量共同影响.淋溶水中Cu、Cr、Ni、Zn、Pb 5种元素的浓度始终在《地下水质量标准》(GB/T 14848-2017)Ⅰ类水质范围内,Cd、As、Hg在Ⅲ类范围内.

In order to explore the influence of applying municipal sludge composting products in Beijing for soil and ground water,the migration and leaching characteristics of eight heavy metals elements(Cu,Cr,Ni,Zn,Pb,Cd,As and Hg)were studied under the conditions of 3,6,12 kg/m^2 composting products added in soil and rain simulating by means of undisturbed soil column experiment.The results showed that Cd remained least(6.1%~11.9%)and leached most(4.5%~7.3%),while Hg remained most(16.0%~22.1%)and leached least(<0.1%).Most Hg,Pb,Ni,Cd and Cu accumulated in the top soil layer(52.0%~78.7%),while most Cr,Zn and As accumulated in the middle layer(42.7%~53.2%).The contents of eight elements in soil all met the national regulation(GB 15618-2018).The concentrations of the six measured elements were in descending order Zn>As>Cd>Cu>Pb>Cr.The relationship among the concentrations and amounts of compost applied and water volume was discussed.According to national regulation(GB/T 14848-2017),the concentrations of Cu,Cr,Ni,Zn and Pb in lechate were always within the range of Class I,while Cd,As and Hg were within the range of Class III.