A lab and field scale evaluation of reducing landfill greenhouse gas emissions with a methane oxidizing biofilter

Landfills are a significant contributor to global methane emissions, with many sites emitting un-treated landfill gas (LFG) into the atmosphere. A treatment approach is to passively vent landfill gas through a methane oxidizing biofilter, which contains a porous medium that facilitates the growth of methanotrophic bacteria. In a lab-scale experiment, two substrates, yard-waste compost and a sand-compost-perlite mixture were evaluated as potential biofilter mediums. The long-term (218 days) removal rates showed that both mediums were capable of removing 100% of the methane influent flux (134 gCH 4·m-2·d-1). A field-scale trial was undertaken by installing three biofilters at the Leduc and District Regional Landfill (AB). Yard-waste compost was used as the biofilter medium. The results showed that two sites performed well, as low surface emissions (< 15 gCH4·m-2·d-1) were generally observed. The third site showed low calculated methane influent flows (< 5 gCH4·m-2·d-1 ), and therefore observations of performance were limited.