基于CALMIM程序的典型填埋场甲烷释放规律分析

Analysis of methane emission of typical landfills based on CALMIM model

运用CALMIM程序对我国3个典型填埋场的甲烷释放量进行了模拟,分析了气候因素、覆盖层表面植被覆盖率以及甲烷氧化对填埋场甲烷释放的影响.结果表明,江村沟填埋场甲烷释放量明显高于老港填埋场和天子岭填埋场,且上海老港填埋场甲烷释放量高于杭州天子岭填埋场;季节因素(如温度、降水)对填埋场甲烷释放影响非常明显,在不考虑氧化情况下,江村沟填埋场最大甲烷释放量出现在8月份,为94 kg/m3,最低甲烷释放量出现在11月份,为65 kg/m3,而天子岭填埋场最大甲烷释放量出现在1月份,为14 kg/m3,最小甲烷释放量出现在9月,为6kg/m3;覆盖层表面植被的存在可以减小甲烷的释放,但甲烷减小的趋势并不是很明显;当覆盖层中最大甲烷氧化速率为50μg CH4gsoil-1d^(-1)时,不考虑甲烷氧化情况下甲烷释放量为考虑甲烷氧化情况下甲烷释放量的6.36倍,当最大甲烷氧化速率大于100μg CH4gsoil-1d^(-1)时,甲烷释放量接近于零.

By using the program CALMIM （California landfill methane inventory model）, the methane emission in three typical landfills of China （ Shanghai Laogang landfill, Hangzhou Tianziling landfill and Xi＇ an Jiangcungou landfill） were numerically simulated, and the influences of climate, vege- tation coverage and methane oxidation rates on emission of methane in landfills were analyzed. The resuits show that methane emission amount in Jiangcungou landfill is obviously higher than that of Laogang landfill and Tianziling landfill, and methane emission amount of Laogang landfill in Shanghai is higher than that of Tianziling landfill in Hangzhou. Two seasonal factors are considered, including temperature and precipitation, without considering methane oxidation, the largest and smallest quantifies of methane emission amount of Jiangcungou landfill are in August and November, which are 94 kg/m3 and 65 kg/m3 respectively. But the largest and smallest quantities of methane emission of Tianziling landfill are in January and September, which are 14 kg/m3 and 6 kg/m3 respectively. The vegetation coverage can reduce the methane emission amount, but this tendency is not obvious. When the maximum methane oxidation rate equals to 50 μgCH4gsoil^-1d^-1, methane emission amount without considering oxidation is 6.36 times that of considering oxidation, and emission amount of methane is close to zero when the oxidation rate of methane is greater than 100μgCH4gsoil^-1d^-1.