METHANE OXIDATION AND DEGRADATION OF ORGANIC COMPOUNDS IN LANDFILL SOIL COVERS

摘要

High rates of methane oxidation and degradation of the lower halogenated methanes (TCM and DCM) and HCFCs (HCFC-21 and HCFC-22) were found in an investigation of the oxidation of methane and halogenated organic compounds (HOCs) in landfill gas affected soil. The degradation followed zero-order kinetics and occurred in parallel with the oxidation of methane. TeCM, CFC-11, and CFC-12 were not degradable in presence of oxygen and degradation of these compounds in the oxidative zone in landfill top covers is therefore expected to be limited. However these compounds were found degradable in the anaerobic zone in the lower part of soil columns permeated with artificial landfill gas. The lesser-chlorinated compounds were degraded in the upper oxic zone with overlapping gradients of methane and oxygen. Methane oxidation and degradation of HOCs in top-soils may play a very important role in reducing the emission of both methane and trace components into the atmosphere.