Retardation Characteristic Of Solidified Sludge Utilizated As Liner Material In Waste Landfill

There are many enviornmental engineering questions need to be solved in municipal solide waste sanitary landfills, in which to prevent seepage of leachate from landfill into environment is one of the most important problems. At the same time, resourceful disposal of urban sludge is now the resources and the environmental research important topic. Accrodding to the anti-seepage request and the characteristic of landfills, the mechanism of sludge solidification body to retardance leachate used as landfill liner was studied by theoretical analysis, laboratory experiment and microscopic structure test. The results are provided the rationale and the technical support for comprehensive utilization of urban sludge and for new liner material development design in landfill. The main research contents and results in this paper are summarized as following:(1)The research status of urban sludge and its disposal were summarized. The physical composition, chemical composition, and disposal methods were analyzed in detail. Then, the sludge solidification processing and the physics, chemistry and mechanics characteristic of sludge solidification body was systematic studied.(2) The strength characteristic of solidification body was studied by experiment. The influence of mixture ratio of sludge solidification on the strength of sludge solidification body was researched, the results indicate that the strength of sludge solidification body increase along with the component quantity increase, and the suitable mixture ratio of sludge solidification body for the following permeability and adsorption test was selected.(3) Permeability of sludge solidification body to leachate was researched. The influences of contaminant concentration, temperature of leachate, and other factors on permeability are studied by laboratory experiment, and the anti-seepage effects and characteristics of sludge solidification body to contaminant such as heavy metals solution, organic material solution, and distilled water were studied.(4) Adsorption mechanism and property of sludge solidification body to contaminant were studied. In the study, adsorption was firstly described as a function of sludge solidification body, the factors of adsorption were discussed, the adsorption characteristics of heavy metals and organic matter on sludge solidification body were studied with equilibrium experiment. The evidence shows that the adsorption mechanism of sludge solidification body conforms to Freundlich Model to heavy metals and Linear Model to organic matter, respectively.(5) The scanning electron microscopy(SEM), mercury intrusion porosimeter(MIP) and fractal theory were used to test and analyze the surface quality and microstructure characteristics of the sludge solidification body.