垃圾填埋场生化降解指标测试及液气产量评估

以上海某综合垃圾填埋场作为研究对象，钻取不同龄期的生活垃圾测试固液气生化降解指标，并对全场的渗滤液产量以及填埋气产量进行评估.经过测试和计算，该处区域已开始稳定产甲烷，进入慢速降解阶段.其中，固相垃圾样的C/L（纤维素与木质素的比值）大部分集中在0.72~1.53之间；渗滤液pH值介于7.91~8.92，BOD介于1050~5780mg/L，COD介于2640~15200mg/L，NH₃-N介于2110~4360mg/L.引入固相、液相以及气相归一化指标β₁、β₂、β₃，用于评估填埋场降解阶段.其中，β₁介于0.56~0.83，β₂介于0.65~0.76，β₃介于0.97~1.02.β₁与β₂能够作为判定垃圾场降解阶段的指标，但β₃只能作为判定垃圾场是否处于稳定产甲烷阶段的指标.另外，建立考虑垃圾压缩-渗流耦合作用的渗滤液产量计算方法，垃圾自身渗滤液产率在70%~80%左右；采用垃圾两阶段降解模型计算填埋气产量，随着垃圾停止入场填埋，填埋气可收集量快速降低，至2025a降至峰值的3.88%，至2040a降至峰值的0.08%.

Biochemical degradation index test and liquid-gas production evaluation of waste landfill

Taking a comprehensive waste landfill in Shanghai as the research object, the municipal solid waste samples were drilled for testing of biochemical degradation index. The results showed that the waste in the testing area has begun to produce methane stably, and it entered the slow degradation stage. Among them, the C/L(the ratio of cellulose and lignin) values of solid waste samples range from 0.72 and 1.53; pH values of leachate were between 7.91 to 8.92; BOD values were between 1050 and 5780mg/L, COD values were between 2640 and 15200mg/L, NH₃-N values were between 2110~4360 mg/L. The normalized indexes β₁, β₂, and β₃ for solid, liquid and gas phases were introduced to evaluate the degradation stage of the landfill. Among them, β₁ values were between 0.56 and 0.83; β₂ values were between 0.65 and 0.76; β₃ values were between 0.97 and 1.02. β₁ and β₂ could be used as the indicators determining the degradation stage of landfill, but β₃ could only be used to determine whether it is in the stable methane production stage. In addition, the calculation method of leachate production considering the coupling effect of compression and seepage was established. The leachate production rate from waste was around 70%~80%. The landfill gas production was calculated using the two-stage degradation model. As the waste stops landfilling, the landfill gas production rapidly decreased, and it would drop to 3.88% of the peak value by 2025 and would reduce to 0.08% of the peak value by 2040.