Analysis of the safety control range of the landfill gas horizontal delivery on the MSW dumping site
HUANG Chuan~1, HU Gang~1, LIU Yuan-yuan~2, JIANG Uang-wei~3(1 College of Resource & Environmental Science, Chongqing University ,Chongqing 400044, China; 2 College of Urban Construction andEnvironmental Engineering, Chongqing University, Chongqing400045, China; 3 Chongqing Environmental Sanitation Bureau,Chongqing 401147, China)
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 pollution 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 CH_4 and H_2S 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 CH_4 is found to reach a maximum value of 66.42% while that of H_2S gets to 10 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.