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

以重庆某非规范填埋场为例,针对西南地区已封场非规范垃圾填埋场的稳定化进程进行了分析。按照场地布局选取4个采样点,在垃圾体上进行钻孔取样,分析不同深度的垃圾样pH值、有机质、含水率、生物可降解度以及垃圾样浸出液和填埋气组成以及各个指标随着填埋深度的变化规律,确定不同深度垃圾体的稳定化程度。结果表明,场内垃圾已呈现矿化垃圾特征;有机质、BDM、浸出液COD以及填埋气CH4含量等4个指标与填埋深度均较好地符合一级降解反应,可以预测垃圾体稳定化临界填埋深度。根据有机质、BDM、浸出液COD以及填埋气CH4含量等4个指标与填埋深度一级降解反应函数预测临界稳定化深度为15 m,与实测值判定的稳定化填埋深度相一致性。在对非规范垃圾填埋场场地利用过程中,需要先对未稳定的上层垃圾进行清理,并在已稳定的底层垃圾体上充填其他稳定介质后利用该地块。

Stabilization progress of wastes in a closed non-standard municipal solid waste landfill in southwest China

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.