Minimization of Methane and Selected Aromatic Hydrocarbons Emissions from Municipal Landfill in Biofilters - a Field Study

Discussion on counteracting the greenhouse effect focused on the reduction of CO2 emissions mainly from the fossil fuel burning. There is often forgotten that the important role in greenhouse effect play other gases, such as methane, but its production is weakly associated with the combustion of fossil fuels. The global warming potential for methane is approx. 25-fold higher than that of CO2. Methane is located at second place on the list of the substances responsible for rising the temperature of the Earth' atmosphere. Taking into account the global action towards prevention the climate changes, a reduction of methane emissions should be enhanced. It could significantly improve the atmospheric air quality. The aim of the study was to evaluate the efficiency of bio-oxidation of methane and selected aromatic hydrocarbons emitted from municipal solid waste landfills. The research was carried out under field scale for 10 months, from early summer to early spring. An open type biofilter worked at variable loading rate of landfill gas and under different climatic conditions. Due to the low gas pressure inside the waste body, the gas suction was applied to provide a continuous gas flow to the biofilter. This was resulted in landfill gas dilution by atmospheric air migrating through the leakiness in the gas supply system. The study showed that the temperature was limiting factor in the processes of bio-oxidation of methane and monoaromatic hydrocarbons such as BTEXs in field scale biofilter. During winter season the realbed temperature fall below 0 degrees C throughout the whole profile of the biofilter. This led to the freezing of the water contained in the soil pores, which prevented the flow of gas along the biofilter. In other seasons, where the average bed temperature ranged from 5.5 to 42.3 degrees C, biofilter worked reaching the 100% efficiency of BTEXs removal, at average mass loading rate of 26.75 ug BTEXs m(-2) d(-1), and 42% efficiency of methane removal at average mass loading rate of 14.6 g CH4 m(-2) d(-1). High efficiencies of volatile organic compounds (VOCs) removal from landfill gas can be explained by dilution of gas stream entering the biofilter with the atmospheric air. Calculation of elimination capacity of particular VOCs and the evaluation of the impact of VOCs concentration on removal efficiencies was impossible due to their total oxidation in the biofilter.