简易生活垃圾填埋场填埋气体横向迁移安全控制范围

Analysis of the safety control range of the landfill gas horizontal delivery on the MSW dumping site

以重庆市兴隆垃圾填埋场为例,在垃圾场东南侧布设17口监测井,对监测井中填埋气进行监测分析。根据填埋气主要组分CH_4和H_2S体积分数的变化,研究相似地质条件下垃圾填埋场填埋气的横向迁移现状及影响区域,确定安全控制范围。结果表明,对填埋气体主要在第四系松散堆积层空隙介质中迁移的简易填埋场,填埋气的横向迁移现主要集中在场界外50 m区域内,监测井中CH_4体积分数最高达66.42%,H_2S最高达10^(-5);填埋场场界50 m以外区域中填埋气的横向迁移非常微弱。因此,在距填埋场场界50 m处采取控制措施可有效控制填埋气的横向迁移。

This paper takes Xinglong dumping site in Chongqing Municipality as its focus to bring about an analysis of the pollution problem caused by the horizontal migration of landfill gas and the safety control range of the MSW dumping sites. As is known, dumping sites are still used as the chief approach to municipal solid wastes （MSW） treatment in China, which has become a severe environmental pollution source. Therefore, it is of imperative nature to reclaim such dumping sites to better control the eco-environmental pellution and remove the hidden environmental hazards as the landfill gas horizontal migration. In the southeast to the dumping site, 17 monitoring bores are regularly laid out to monitor the bulk fraction of the landfill gas from the bores. It is found that CH4 and H2S are characteristic components of the landfill gas, which we have chosen to check the horizontal migration regularity of the gas formulation. The results show that such gas is mainly concentrated in the region with a distance to the MSW dumping site boundary less than 50 m and then migrating into the quaternary loosen soil. Of the two, the bulk fraction of CH4 is found to reach a maximum value of 66.42% while that of H2S gets to 10^-5 in such monitoring bores. In addition, statistical analysis of their horizontal migration indicates that the distance to the dumping site boundary and the depth of the quaternary loosen soil are closely correlated with the bulk fraction of the above said two gases in the bores with the main influential factor being the distance to the dumping site boundary. However, weak horizontal migration of the landfill gas can be found in the regions at a distance over 50 m to the site boundary. And, consequently, it should be taken as the special horizontal migration security control area, where some engineering measures should also be taken to control such horizontal migration.