Study On Acceleration Of Waste Stabilization In Semi-aerobic Landfill

In the process of waste treatment,no matter what treatment motheod is adopted,the residues(such as incinerator ash or the part that cannot be recycled in the process of resource recovery)will be generated for disposal in the landfill sites.Since most landfill methods are sanitary landfill,the stability of waste needs a long time,so how to accelerate waste decomposition has become an important problem to be solved urgently.In addition,the waste classical has not been carried out worldwide,especially in developing countries,and the kitchen waste is account for more than half.The high water content of kitchen waste will affect the air flow into waste layer from leachate collection pipe in the semi-aerobic landfill.In this experiment,the lab-scale semi-aerobic landfill simulation reactors were established.The waste sample used in landfill reactor included Municipal Solid Waste(MSW).The structure of the landfill reactor and the void fraction of the waste were changed to further research on the influence factors of waste decomposition and the influence of void fraction on waste decomposition.When the influence factors of waste decomposition were investigated,it was found that the void fraction of waste and the structure of the reactor had obvious impact.The results showed that the void fraction of waste in reactor A and C was 29.79% and 30.86% respectively,and that of waste in reactor B 34.96%.Compared with reactor A,reactor B had its temperature increase earlier.In addition,the temperature distribution in vertical gas vent of the reactor A and B is higher than in the leachate collection pipe.The gas flux of vertical gas vent increased with the temperature of gas vent.In reactor C(without vertical gas vent),the temperature inthe reactor was similar to the temperature of indoor air.In the further analysis of the influence of void fraction on the decomposition of waste,lab-scale semi-aerobic landfill simulation reactors were established.The void fraction in reactor A?,reactor B?,reactor C? and reactor D? was 33.76%,39.84%,44.62%,and 41.31%,respectively.The void fraction was increased properly(reactors C? and D?)would made the air flowing into the waste layer,enlarged the formation of aerobic zone and promoted the decomposition of waste rapidly.In addition,the distribution of gas concentration in the pipeline can determine the flow path of gas and the decomposition of organic matter in the device.To sum up,the cvertical gas vent playes an important role in promoting waste decomposition in semi-aerobic landfil.In the other word,the function of the vertical gas vent was not limited to exhausting gas,but also to promoted the formation of an aerobic zone the rapid decomposition of organic matter,ccelerate the process of garbage stabilization.Meanwhile,the void fraction of waste would directly affect the gas flow path.If the void fraction was small,the air was difficult to flow into the waste layer,and the removal efficiency of COD and NH3-N was low.This study would providesome data for the future research of landfill included high organic matters,especially in the developing countries where the waste classification has not been carried out.It would offer a theoretical basis to explore a suitable landfill technology for them.