考虑生物降解情况下填埋场温度的预测

The Prediction of the Temperature Distribution in Landfill Under the Consideration of Biodegradation

为了探究外界温度对填埋场内部垃圾的降解、温度分布、有机物消耗的影响,在两阶段降解模型基础上建立了考虑温度影响的降解模型.通过计算填埋场中发生的主要的几种生物化学反应的焓变,得到垃圾在各个反应阶段的产热量用来分析填埋场内垃圾的产热规律.通过水解酸化和产甲烷两个阶段来描述填埋场的厌氧降解过程,将降解方程和热传导方程结合得到预测填埋场温度变化和降解规律的模型.分析了不同外界环境温度下,填埋场内部温度、VFA浓度、厌氧微生物浓度和有机质含量的变化规律.研究结果表明,外界温度对填埋场内的最高温度以及最高温度出现的时间有较大的影响;同时外界温度对可降解有机物降解完成所需的时间也有较大的影响,当外界温度为5℃时有机物降解完成所需要的时间是外界温度为20℃时所需时间的2.1倍.浅层垃圾受外界温度波动影响较大,垃圾中有机质的降解比中部慢.

In order to study the influence of external temperature on landfill degradation,temperature distribution and organic matter consumption,a two stage degradation model considering the influence of temperature is established. In this paper,the enthalpy change of several biochemical reactions occurring in landfills are analyzed to calculate the heat production of MSW. The anaerobic degradation process of landfill is divided into two stages of hydrolytic acidification stage and methane production stage. Combining the degradation equation with the heat conduction equation,a model for predicting the temperature change and degradation law of MSW is obtained. The temporal and spatial distribution of temperature,VFA concentration,MB concentration and the organic content in landfill are analyzed.It can be obtained that the external temperature has a great influence on the maximum temperature and the time to reach the maximum temperature in the landfill. At the same time,the external temperature has a great influence on the time which is required for the consumable completion of degradable organic materials. When average ambient temperature is 5 ℃,the time requiring for the completion of the organic matter consumption is 2.1 times at 20 ℃.