电阻率法在磷石膏渗滤液污染检测的试验研究

Experimental Study on Feasibility and Physical Properties of Leachate Pollution Detection in Phosphogypsum Storage Yard When Using Electrical Resistivity Method

磷石膏作为磷化工废渣之一,当处置不当致使其中的渗滤液析出时,会对周边区域水土造成污染。直流电阻率法虽已开始应用在环境污染调查等领域,但专门针对磷石膏渗滤液电阻率特征及其对土体电阻率影响的研究还鲜有报道。为此,该文首先选用NaCl、NH_(4)H_(2)PO_(4)溶液模拟磷石膏渗滤液并进行了溶液电阻率测定,结果表明,溶液电阻率在低浓度区段变化最为剧烈,该范围内污染物浓度的细微改变即可导致电阻率发生较大变化。从贵州某磷石膏堆场采集的渗滤液测定结果也表明,渗滤液电阻率远低于当地正常地下水的电阻率值。加入不同浓度溶液的土体样本物性试验和场地试验结果都表明,当土体受到一定污染时,由于其孔隙水中离子浓度的升高,都会造成土体整体电阻率的降低。物性实验结果表明,电阻率法对于检测磷石膏渗滤液的污染具有一定的有效性。

Phosphogypsum,as one of the phosphorus chemical waste residues,will pollute the surrounding water and soil when the leachate is precipitated due to improper disposal.Although DC electrical resistivity method has been applied in the field of environmental pollution investigation,there are few reports specially on the resistivity characteristics of phosphogypsum leachate and its influence on soil resistivity.Firstly,NaCl and NH_(4)H_(2)PO_(4)solution are selected to simulate phosphogypsum leachate and their resistivity has been measured.The results show that the resistivity changes most dramatically in the low concentration range,and a small change in the concentration of pollutants in this range can lead to a large change in the resistivity.The measurement results of leachate collected from a phosphogypsum yard in Guiyang City,Guizhou Province also show that the resistivity of leachate is far lower than that of local normal groundwater.Finally,both the physical property experiment results of soil samples with different concentrations of solutions and the field experiment results show that when the soil is polluted,the overall resistivity of the soil will be reduced due to the increase of ion concentration in pore water.The preliminary experiment results show that the resistivity method is effective for detecting the pollution of phosphogypsum leachate.