页岩改性粘土作为垃圾填埋场防渗衬垫试验研究

Experimental Study on Shale-modified Clay as Impermeable Liner of Landfill Site

为了研究页岩作为垃圾填埋场粘土防渗衬垫改性材料的可行性,通过页岩颗粒的吸附试验和粉碎页岩改性粘土材料的渗透试验,考察其对渗滤液中主要污染物NH4+、COD的吸附情况和确定满足填埋场衬垫渗透要求的粉碎页岩添加量。实验结果表明,页岩颗粒对垃圾渗滤液中NH4+达到吸附平衡需要24 h,对COD需要48 h。在吸附效果方面,页岩颗粒粒径在0.075mm以上时,对COD具有较强的吸附能力,吸附率在57.57%～61.75%之间,明显高于膨润土等土样;对NH4+吸附能力弱些,吸附率在27.21%～31.21%之间。粉碎页岩添加量在10%范围内时粉碎页岩改性粘土材料的渗透系数能够达到1×10-7cm/s以下,满足填埋场防渗衬垫的渗透要求。

In order to study the feasibility of shale as the modified material of impermeable clay liner of landfill site, the shale particle absorption assay and crushed-shale modified clay material＇s penetration test are made to examine its adsorp- tion performance for major pollutants of NH4^＋and COD in leach liquor, and determine the shale amount that would meet the liner penetration requirements of landfill site. The experimental results show that the adsorption equilibrium for shale to NH4^＋ requires 24 h, and that to COD requires 48 h. In the adsorption effect, when the shale particle size is greater than 0.075 mm, it has strong adsorption capacity to COD, its adsorption rate is between 57.57% and 61.75%, signifi- cantly higher than that of other soil samples; while it is weaker to NH4^＋ in the adsorption capacity, its adsorption rate is 27.21% to 31.21%. When the crushed-shale amount is in the range of 10%, the permeability coefficient of modified clay material is lower than 1 x 10^-7 cm/s, which could meet the penetration requirements of the clay cushion of landfill site.