THE INFLUENCE OF LANDFILL FEATURES AND SIDE SLOPES ON METHANE EMISSION RATES

Sanitary landfills for Municipal Solid Waste (MSW) disposal have been identified as one of the most important sources of methane (CH4) emissions; indeed, MSW contains a certain amount of biodegradable organic matter which undergoes anaerobic degradation resulting in the production of the so called landfill gas (LFG), which main component is typically represented by CH4. In general, LFG will escape through any faults in the landfill capping or in the LFG collection system. If the capping is not damaged, low quantities of LFG will be emitted through the permeable material that covers the disposed waste. On the other hand, some zones of the capping are often more permeable than others (e.g. side slopes), mainly when a temporary capped zone is used. Such zones, which can be characterized by abnormal emission, are usually defined as “features”: in particular, a feature is a small, discrete area or an installation where CH4 emissions differ from the surrounding zone. In the present study, the influence that specific features have on CH4 uncontrolled emissions has been investigated, based on direct measurements carried out by means of a flux accumulation chamber (static, non-stationary), coupled with a Flame Ionization Detector (FID) device; such method was applied to the case study of Palermo (IT) landfill (Bellolampo). Further, through the use of a geostatistic methodology, the direct measurements of CH4 fluxes from the landfill surface have been used to obtain the total amount of methane emitted from the investigated area as well as the methane flux maps.