采用静态箱法监测了2个生活垃圾填埋场春、夏季及昼夜的CH4释放通量,并分析了影响CH4释放的相关因素。结果表明:填埋气体(LFG)主动收集对填埋场CH4释放的影响显著。在填埋龄相近的条件(4.0~4.5年)下,无LFG主动收集的填埋场春、夏季CH4的释放通量(以CH4计)平均值[(541±1005)mg/(m^2·h)]比有LFG主动收集的填埋场提高4.4倍。在有LFG主动收集的填埋场内,填埋龄为1.0~1.5年的非渗滤液灌溉区的CH4释放通量均值[(324±847)mg,(m^2·h)]为灌溉区的10.0倍左右。在有LFG主动收集的填埋场内,CH4释放通量与各环境因子间无显著相关;而在无LFG主动收集的填埋场内,CH4释放通量分别与覆土温度和气温呈显著正相关,与大气压强呈显著负相关。相关性分析结果表明,CH4释放通量与填埋场覆土中含水率,ω(有机碳)和ω(总氮)呈显著正相关。
CH4 emissions from two full-scale sanitary landfills for municipal solid waste (MSW) were investigated by static chamber method hased on the diurnal and seasonal variations in spring and summer. The influencing factors on landfill CH4 emissions were evaluated as well. The results indicated that CH4 emissions could be minimized substantially by landfill gas (LFG) recovery system. Comparing similar landfills with ages of 4.0-4.5 years, the average CH4 flux [(541±1,005) mg/(m^2·h)] from the landfill site without landfill gas recovery was 4.4 times larger than the landfill site with landfill gas recovery. In landfill sites with landfill gas collection, comparing similar landfills with ages of 1.0-1.5 years, the average CH4 flux [(324±847) mg/( m^2·h)] from the test lifts without leachate irrigation was 10.0 times larger than those from the test lifts with leachate irrigation during the spring and summer measurements. In the landfill sites with LFG collection, CH4 fluxes were not significantly correlated with environmental factors during the measurement, while CH4 fluxes were positively correlated with the soil and air temperature, and negatively correlated with the atmospheric pressure in the landfill site without LFG collection. There were positive correlations between CH4 fluxes and soil moisture, organic carbon and total nitrogen contents in cover soils as well.