Quantitative Study On Effect Of Temperature On Anaerobic Degradation Of Organic Solid Waste In Landfill

The degradation of organic waste in anaerobic landfill is essentially a complicated biochemical process, which involves several kinds of bacteria, degradation phases and its reaction velocity is sensitive to temperature change. When the reaction temperature reaches to 50-60℃, several kinds of enzymes almost lost their activities. So temperature is one of the important factors to the degradation of organic waste in anaerobic landfill.In view of a lack of relative study in this field, the standard for judging degradation phase of municipal solid waste (MSW) in anaerobic landfill was established. Then a simulated experimental study was conducted, which mainly involved the effect of temperature on the characteristics of leachate quality and the composition of the landfill gas. Then, the theorital model of the degradation of the organic waste from landfill leachate was established. Further more, based on the experimental study results, by means of SPSS 13.0, the exponential models were established in the different reaction temperatures, also the quantative formula between the attenuation coefficient of COD concentration from leachate and the reaction temperature was established. Finally, the relative thermodynamic theories were employed in this thesis, the effcct of temperature on the eguilibrium constant of the typical reaction in the methane fermentation phase. Also, the quantative formula between the eguilibrium constant and the temperature was established. At the same time, the author primarily discussed the effect mechanism of temperature in landfill.It was shown from the simulated experimental study that: (1)the simulated columns C4 and C5, whose operation temperature values were controlled at 41℃and 45℃, the COD concentration in leachate dropped from 86614 mg/L, 90000mg/L to 5216.5 mg/L, 5413.4mg/L respectively. The corresponding COD concentration decreased 93.98% and 93.99% respectively. At the same time, the ammonia-N concentration still higher-kept at 1000mg/L, this was the problem faced to the anaerobie landfill. (2)In the process of the production of landfill gas, the composition of methane in landfill gas in the simulated column C4, whose operation temperature values were controlled at 41℃, reached to the maximum value. This made for the recycle and reuse of the landfill gas.By means of the results of parameters estimated and model verified by SPSS 13.0, it is proved that the attenuation kinetic model of COD concentration from leachate was reasonable, and it could describe the COD concentration attenuation rule at different temperatures. According to the results of theoretical analysis, it is concluded that the eguilibrium constant increased with the temperature increased for the typical reaction CH₃COOH =CH₄ + CO₂ in the methane fermentation phase. Then, the quantitative equation between the eguilibrium constant and temperature was established. Contrast with the results of experimental study, the effect mechanism of temperature could be attributed to two aspects: the reaction eguilibrium constant increased with the temperature increased, and the reaction velocity increased accordingly; on the other hand, the activity of the enzyme dropped with the temperature increased.It is proved that controlling the reaction temperature had the great advantage to the control of leachate pollution and the recycle and reuse of the landfill gas. This research can enrich and develop the waste degradation theories; on the other hand, it can supply proof to forecast the stabilization time of MSW in landfill in north and south of China.