垃圾填埋场渗滤液灌溉及覆土土质对填埋场氧化亚氮释放的影响

Effects of leachate irrigation and cover soil type on N_2O emission from municipal solid waste landfill

采用静态箱法,现场监测黏土和砂土覆盖层生活垃圾填埋场N2O释放通量的春夏季节及昼夜变化,研究渗滤液灌溉、覆土土质对填埋场N2O释放的影响.结果表明:砂土和黏土覆盖层填埋场N2O夏季的释放通量均值分别为(242±576)和(591±767)μgN2O-N·m-2·h-1,是春季[分别为(74.4±314)和(269±335)μgN2O-N·m-2·h-1]的3.2(P>0.05)和2.2倍(P<0.05).渗滤液灌溉促进了砂土填埋场覆土N2O的释放,填埋场中灌溉区N2O的释放通量为无灌溉区的2倍(P>0.05).渗滤液灌溉的砂土覆盖层填埋场N2O春夏两季释放通量均值[(211±460)μgN2O-N·m-2·h-1]仅为无渗滤液灌溉的黏土覆盖层填埋场[(430±605)μgN2O-N·m-2·h-1]的1/2(P>0.05).无论渗滤液灌溉与否,选择贫瘠的砂性覆盖土均有助于减少生活垃圾填埋场N2O释放.

By the method of static chamber,the seasonal and diurnal variations of N2O fluxes in two full-scale municipal solid waste（MSW）landfills covered with sandy and clay soils were measured to study the effects of leachate irrigation and cover soil type on the landfill N2O emission.The results showed that the N2O flux in the MSW landfill covered with sandy soil was（242±576）μg N2O-N·m^-2·h^-1 in summer,being 3.2 times（P〉0.05）as high as that in spring [（74.4±314）μg N2O-N·m^-2·h^-1],while the N2O flux in the MSW landfill covered with clay soil was（591±767）μg N2O-N·m^-2·h^-1 in summer,being 2.2 times（P〈0.05）as high as that in spring [（269±335）μg N2O-N·m^-2·h^-1].Leachate irrigation promoted the N2O emission from the soil cover of the landfill covered with sandy soil,and the N2O flux in the landfill was 1 time higher than that of the control（P〉0.05）.Under leachate irrigation,the average N2O flux in spring and summer in the landfill covered with sand soil was（211±460）μg N2O-N·m^-2·h^-1,being only 1/2 of that [（430±605）μg N2O-N·m^-2·h^-1] in the landfill covered with clay soil without leachate irrigation（P〉0.05）.Therefore,no matter leachate irrigation was conducted or not,the N2O emission from MSW landfill could be minimized by covering with infertile sandy soil.