Research On The Law Of Leach-ate And Gas Movement And The Pollution Of Control In The Landfill Of Western Mountain City Of China

With the development of western mountain city of development, and population expand rapidly; the waste quantity increase enormously. These cities need to build a lot of sanitary landfills to disposition garbage. But, due to the economy and science and technology are less dexeloment, there is pollution in the same sanitary landfill. At the same time, there are many simple rubbish dumpings and burials (simple landfills) which built in 80's last century in western mountain city, and these simple rubbish dumpings and burials are serious pollution in environment, and they had didn't adapt current needs. The simple landfill must be close up and renovate. The simple landfill and the sanitary landfill are pollution in environment. Therefore, not only building landfill but also renovating simple landfill, the control pollution must be research. But the pollution is come from the leachate and gas movement. In order of the western mountain city enxironment is beatuful, the leachate and gas movement law and the pollution control must be to research.The studies on landfill pollution control of plain cities are under way, but so far, there is practically no report of studies on that of mountain cities. The research conclusion of plain cities landfills cannot be applied to mountain cities, since landfills of plain and mountain cities differ in topographic and geological conditions, the topography of mountain cities landfills being mostly valley and lithology of stratum in mountain cities being complicated with cranny. Therefore the western mountain city landfill's gas and liquid luck changing law and their contamination control studying is an important urgently problem. In this paper, the author adopts survey and measurement by the scene, theoretical analysis, interior testing and numerical simulation method to study this problem.First, the author analyses the western mountain city garbage and landfill characteristic property, calculate leachate and landfill gas quantity, on this basis, generalize the physics model of leachate seepage, through adjust boundary and parameter reasonably, generalize the fault and rock crack media of the landfill to a porous medium. Then build western landfill mathematic model of leachate seepage, and contrast the values between the density of the leachate,groundwater level which gained by numerical simulation and measured value, then revise this model, and obtain the reasonably mathematical model of leachat movement in mountain city of west china, at same time, the results show that adjust parameters reasonably, it is feasible to adopt porous medium simulate crack medium.Finally, adopt distinguished mathematic model to simulate and analyze leachate seepage and pollution regular pattern of real landfill which the fault had not been renovated, and the remediation landfill which the fault had been renovated. Result indicates that leachate forming a stronger transfusion pollution zone in fault crack, breaks have changed leachate seepage route in structure. In the landfill and on the side of landfill, the COD concentration in the actual landfill which the fault had been not renovated is 800 mg/L and on the side of actual landfill is 2 00 mg/L higher than the landfill with no fault which the fault had been renovated. The leachate concentration in the near the center of landfill is maximal in the real landfill which the fault had not been renovated, but the leachate concentration in south of landfill which the the fault had been renovated.While building western mountain city model and researching on the law of leachate seepage and pollution, establish landfill gas migration model in landfill and outside landfill, solve this model and analyze the situation of landfill gas movement, then contrast the results between simulated value and real measure value, the result is close, explains that the model is accord with objective reality, the gas migration conclusion can provide scientific basis for landfill gas contamination control. The landfill gas movement length is less than or equal to 25 m in the landfill where there is not fault, the length is equal or more than 50 m in landfill where there is fault.By combined reality measures with numerical value simulates method, gets the western mountain city seepage law of landfill leachate and gas, brings forward corresponding landfill environmental pollution measurement, and carries out analysis on controlling the contaminating scheme according to this gas-liquid seepage law. To control leachate and landfill gas penetrate to outside in the fracture structure passing location in western mountain city landfill, we can adopt the method of active periphery exhaust ties with the grout curtain.