Study On Leachate Controls System In Sanitary Landfill Plants Of Municipal Solid Wastes

The technology of sanitary landfill for municipal solid wastes has been adopted since 1980's in our country. Up to now,more than ten sanitary landfills have been built in china and a great deal of sanitary landfills are building or will be building.《the policy about municipal solid wast processing and the technique of pollution treatment》〔established associatedly by national construction department, national environmental protection bureau and national department of science and technology〕point out definitely that sanitary landfill is the main means to treat municipal solid wasts in china in present stage. Therefore we can anticipate that the technology of sanitary landfill will be applicated more and more extensively in china. Though sanitary have numerous advantages, the leachate is a tougher problem during the filling period and the sealing period. Not only the quantity of landfill leachate is big, the polluting strength and polluting characteristics of leachate vary continuously. Numerous research and practice indicate that leachate is not only difficult but also very expensive to treat.It is easy to pollute groundwater if the leachate control system is in trouble or has faults.Leachate control system is analysed particularly in this paper. The water balanced model of soil layers is used in the humidity variable regulation in a garbage body, laying the foundation for the research of moisture transfer mathematics model.A study on electrolytic oxidation process + Immobilization of microorganisms was made for treatment of landfill leachate. The results show that: (1) Sequential Changes of moisture in a garbage body can be described in smaller dimensions of time and space by Seepageflow mathematic model. Although a lot of parameters are involved in Seepageflow mathematic model,they are all a function that contains the water rate θ.therefore, the variety regulation of the water-holdup(θ) count for much. the water rate θ changes along with rainfall and evaporation.Normally,The inital water-holdup profile is knowen.So,it is easy to obtain the water-holdup profile in a garbage body if the increment of the water-holdup profile is conformed. (2)After artificial rainfall begins, the increment of moisture of each layer reduces gradually from the top of the garbage body to bottom. In regard to some one depth,the increment of moisture is deceided by rainfall and average field capacity and the parameter K value which reflect the even characteristic of garbage body. Actually, the internal structure of garbage body is not uniform and the field capacity is also different in different layers. The density of solid wasts is smaller, the K value is smaller, the seepage ability of garbage body is stronger, the seepage can attain bigger depth into the garbage body.Vice versa.The experiment of artificial rain process indicated that permeating coefficient of precipitation have no obvious regulation in different rainfall conditions. Therefore, it can be concluded that permeating coefficient of precipitation is mainly decided by the section character of garbage body and no relation to rainfall.(3)The force act on seepage-flow by holes in a garbage body mainly involves gravity and capillary pressure.But capillary pressure only act on some of holes in a garbage body,that is to say,there are non-capillary holes among holes in a garbage body. The force act on seepage-flow by non-capillary holes is mainly gravity. Because the capillary pressure is usually far larger than the gravity, seepage is divided into two kinds.One is capillary-flow which seep fast by capillary holes.The other is gravity-flow which seep slowly by non-capillary holes.(4)The electrolytic oxidation process in removal of pollutants is divided into two kinds.one is direct-oxidation process in which the pollutant was directly oxidize or restore in the electrode surface.The other is indirect-oxidation process in which a chemistry occurrence between electric particles and pollutants make the pollutants processed indirectly. The direct-oxidation processing is divi...