Study On Alternative Liner For Landfill

The essence of landfill is to control the spread of pollutants in a particular region and acceptable level with encapsulation methods of Civil Engineering. In this sense, the low permeability coefficient and the obvious obstructing effect of pollutants is extremely important for the landfill liner. Therefore, clay or other synthetic materials are preferred for material of liner. The China's "Municipal Solid Waste Sanitary Landfill technical standards" have been issued in 2007. This standard requirement that the landfill liner could use all possible soil materials if the permeability coefficient no more than 1×10^-7cm/s.So this standard provide the possible for designing the appropriate liner.Considering the pollution control, the implementation of the design of encapsulation is not only. In other words, different designs can achieve the same effect of pollution control.Therefore, the scientific landfill design should emphasize particularly on pollution control standards, allow to adopt "alternative" liner as long as meeting pollution control standards.In this paper, we firstly consider the alternative meteral of liner. Select the loess that distribute broadly in the northwest of china to test the mixed soil (loess- bentonite, loess-cement, loess-lime, loess-fly ash) hydraulic conductivity. The results show that bentonite can effectively reduce the hydraulic conductivity of loess. The other three modifiers can enhance the strength of loess, but it can not reduce the permeability of loess. Then, we use the convection - dispersion equation of soil to calculate pollutant taking into the adsorption of Zn²⁺,Cd²⁺ for loess. The results show that the accumulation of pollutants of thicker loess liner equal to the clay liner, and the attenuation of pollutants is 80%～90%. This result shows that the alternative liner can achieved the same blocking effect for pollution through increasing the thickness of liner.