Study On Stabilization Of Refuse In The Makeshift Dumps Of Three Gorges Region

The first water storage of the Three Gorges Project will start in June, 2003, then current rate of the Yangtze River will decelerate, with an ability of self-purification lower than before. But in the drown area there is a large quantity of municipal solid waste heaping along the river which is becoming a threat to ecological environment and water quality of the Reservoir. The solid waste below the drown line of the Reservoir must be validly cleaned before water storage, and only this can ensure the water quality of the Reservoir. Therefore, availably dealing with the refuse in the reservoir area to alleviate its pollution to water environment of the Three Gorges reservoir has become an urgent and important mission of environmental protection.The overall investigation shows that there is rough 3.30 million tons of municipal solid waste (MSW) heaping in the Three Gorges region, more than 140 heaps. The refuse with complicated composition is mostly along the river optionally, and there are all kind of heaps, big and small, long and short in stabilizing time.According to the degradation theory of refuse, leach, refuse gas, the settlement of the heaps and the constitution of solid waste will change with the extension of piling time of heaps. When the organic matter in the MSW is in a comparatively low level, the refuse degradation speed will decline. When there is little organic matter in solid residue, the dumps have stabilized. At the time, the refuse would only influence water environment little.The judgment of stabilization status in the reservoir is important to clean solid waste in the bottom of Three Gorges reservoir. The stabilization status of refuse can be described with the quantified macroscopic or microscopic indexes. The paper adopts both the microscopic indexes and some macroscopic indexes, and the macroscopic indexes include appearance index, maximum gas output, stabilization time, the plastic content in the refuse and the settlement of dumps. The microscopic indexes include organic matter content, some polluting indexes of refuse leach. Among them, because of some special circumstance, and the index of the settlement of dumps is not adopted. There is no correlation between the plastics content and the stabilization character of the refuse in the Three Gorges region. In the paper the index system involves appearance index, maximum gas output, stabilization time, the organic matter content in the refuse, COD content in the leach of refuse dumping in the Three Gorges region. There are 4grades in the stabilization rating system, not stable, basically stabilized, well-stabilized and completely stabilized.After setting up the index system, the refuse in the large typical dumps is sampled, the related indexes are measured, and some kinds of physical and chemical characters are analyzed.Applying index system and dates obtained from the experiment, with fuzzy assessment the stabilization status of the refuse in the dumps below the drown line is evaluated, the conclusion is that 50.78% has already stabilized, 38.2% is already well stabilized, 7.12% basically stabilized, and 2.96% is not stable. The outcome is consistent with the analysis to the appearance index. Finally, several maximum typical dumps are analyzed in particular; this can direct the cleaning of the reservoir bottom in a large extent, in future.