三种无机改性粘性土防渗衬里性能研究

利用三种无机材料沸石、粉煤灰、石灰对目前常用的粉质粘土+膨润土进行改性,以新鲜垃圾渗滤液作为渗透液,从防渗衬里的渗透系数以及对污染物的衰减能力方面进行了对比实验,对三种无机改性防渗衬里的性能进行了研究。实验结果表明:(1)石灰改性的防渗衬里防渗效果最好,其渗透系数能保持在10-8～10-9cm/s;沸石和粉煤灰改性的防渗衬里渗透系数也能达到10-8cm/s,并且随着实验的进行,渗透系数有所下降;(2)改性后的粘性土防渗衬里对污染质的衰减能力强于改性前:其COD的平均衰减百分比由改性前的68.25%分别升高到72.47%、86.94%和89.64%;对三氮的衰减百分比均有提高;对总铁平均衰减百分比为90%以上,对镉、锌也都表现出良好的去除效果。

Study on the Performance of Three Inorganic Modified Liners

An experiment was done to modify the mixture of silty clay and bentonite respectively with zeolite,fly ash and lime.Experimental results indicated that the permeability coefficient of lime modified liner is the lowest,with 10-8～10-9cm/s,the permeability coefficients of zeolite and fly ash modified liners are also up to 10-8cm/s.As the experiment went on,the permeability of the compound liner decreased gradually.Modified liners have better stability on the attenuation of the pollutants than the mixture of silty clay and bentonite liner,with average attenuation percentage of COD increased from 68.25% to 72.47%,86.94% and 89.64%.Average attenuation percentage of NH4+,NO2-and NO3-are improved too,average attenuation percentage of iron reaches to 90%,and with better removal efficiency on cadmium and zinc.