Stabilization progress of wastes in a closed non-standard municipal solid waste landfill in southwest China
西南地区某已封场非规范垃圾填埋场垃圾稳定化进程分析

Taking a closed non-standard municipal solid waste (MSW) landfill in Chongqing as an example, the stabilization progress was studied for non-standard MSW landfill sites in southwest China. Based on the specific layout of the site, 4 sampling holes were drilled and solid waste and landfill gas samples were taken at various burying depth. The change trend of the pH value, organic matter content, moisture, biodegradable matter content and leachate of the solid waste samples, and the compositions of landfill gas with the burying depth was analyzed to determine the stabilization status of the solid wastes at different dept. The results show that the wastes in the landfill represents the characteristics of mineralized wastes; the change trend of organic matter contents, BDM (biodegradable matter) contents, COD in the leachate of waste samples and CH4 content in landfill gas with the burying depth follow first order degradation reaction and therefore the critical stabilization depth can be predicted. The critical stabilization depth is determined to be 15 m, which is very much consistent with the results from the practical monitoring data. Therefore, during the utilization of MSW landfill site, the unstable upper MSW layer should be excavated first, and then the new development may be carried out on the deep stable MSW layer following some proper treatment.