城市生活垃圾降解–压缩特性试验研究

Experimental study on biodegradation-compression properties of municipal solid waste

为了研究垃圾土在好氧和厌氧阶段因外部温度场的变化对降解特性的影响,选取重庆市某垃圾场作为研究对象,进行了两种不同温度控制的降解试验,同时对渗滤液中可溶解有机碳含量进行了追踪测试,试验结果表明:1不同有机物含量垃圾土试样,当外部温度场小于22℃或者大于45℃时,温度对有机质降解的影响较小;2当温度在22℃~45℃时,根据垃圾土产气量、渗滤液溢出量以及质量损失率得出此温度区间对垃圾中有机质的降解起明显加速作用,降解反应程度在41℃时最大;3根据温度–质量损失率关系,推导了考虑温度效应的分阶段垃圾土降解率计算模型,并且得出垃圾土的降解率在0~180 d符合自然降解规律,为时间的函数;在180~360 d,降解率为时间和温度的双重函数;模型验证结果表明,计算结果与试验结果能够比较好的吻合。

In order to study the effect of external temperature on the biodegradation properties of municipal solid waste (MSW) at both aerobic and anaerobic phases, two kinds of controlled temperature fields are applied during the biodegradation tests in the laboratory, and the dissolved organic carbon is monitored and recorded using the reconstructed fresh shredded MSW with different organic contents, collected from landfills located in Chongqing. During the experimental process of 0~360 days, the biodegradation tests result show:(1) When the external temperature field is less than 22℃or more than 45℃, the effect of temperature on the biodegradation is proved to be limited and the degradation conforms to the natural process. (2) According to the monitored data of biogas, leahcate production and losses of quality of MSW when the external temperature varies from 22℃to 45℃, the effect of temperature on the biodegradation of MSW is gradually obvious. Moreover, the degradation speed of MSW reaches the maximum value when the temperature reaches 41℃. (3) Based on the experimental results of leachate production and settlement, a divided new mode of degradation rate for MSW is proposed which can better consider the temperature effect. From 0~180 days, the biodegradation rate of the model is time-depended, and the rules of biodegradation are fitting to the natural decomposition of 0~180 days. However, the biodegradation of MSW in later biodegradation tests must consider the temperature effect and the degradation is the function of time and temperature from 180~360 days. In the end, the comparison between the model calculations and test data proves that the proposed divided model can fit the experimental data very well.