Experimental investigation of landfill gas emissions in high emission areas or 'hotspots'

Published results indicate that there is significant variation in landfill gas emissions. Researchers have documented the presence of high emission areas, often referred to as hotspots. Hotspots are commonly associated with areas on the soil cover that are barren of vegetation. Although it is generally recognized that emissions are concentrated in these relatively small areas, no significant work has been done to gain a full understanding of the nature of the landfill gas flow regime in these zones.;Column reactors were constructed and exposed to a range of simulated landfill gas flows. Field measurements were made at two different landfills. Dynamic flux chambers were used to measure landfill gas flux rates and innovative sampling stakes were used to measure soil-gas concentrations at depth.;Results obtained from the columns indicate methane oxidation rates ranged from 0.051 to 0.098 L/m2/min. Flux chamber measurements indicate that methane emission rates ranged from 0 to 2.3 L/m2/min. The results indicate that emissions are concentrated at visible soil anomalies like holes or fissures. Two methods were developed to estimate the emission rate through a hole or crack. Results rates ranged from 60 L/m2/min to 30 000 L/m2/min. The work shows that standard chamber techniques are not suitable for very high emission locations. It was determined that standard methods may significantly overestimate flux rates. The sampling stake was used to obtain in-situ soil gas profiles.activity Profiles measured near holes or cracks, exhibiting extremely high emissions, suggest that numerical modeling based on assumptions of homogeneous isotropic media may be inappropriate for these areas.;The information gathered made it possible to design a simple and cost effective remediation technique that has the potential to help mitigate emission at any landfill facility.;The objective of this thesis was to augment the body of knowledge on landfill gas transport in high emission areas. Methane oxidation by soil bacteria in the cover has been recognized as a significant sink. The overall goal was to develop a practical method of providing an environment that would maximize bacterial growth and therefore minimize methane emissions.;Keywords: Landfill Gas, Emissions, Hotspot, Flux Chamber, Soil-Gas Profiles, Methane, Methanotrophs.