Utilization of stabilized wastes for reducing methane emission from municipal solid waste disposal

• Stabilized wastes could be utilized for reducing methane emission from landfill.
• Maximum methane oxidation rate of 34.1 g/m3 d was obtained over 180 d.
• Methanotrophic activities of plastic and fine waste fraction were at same level.
• Plastic wastes facilitated oxygen supply for methane oxidation in the waste layer.
• Methanotroph type I was found predominant over the entire depth of waste layer.

Stabilized solid wastes were utilized to mitigate methane emission from the landfill. Loose texture of plastic wastes encouraged air diffusion from the soil surface whereas fine organic fraction has good water holding capacity and nutrients to stimulate methane oxidation reaction. Biological methane oxidation capacity in stabilized waste layer was found to be up to 34.1 g/m3 d. Microbial activity test revealed methanotrophic activities of plastic and degraded organic wastes were in the same order. The mixture of plastic and fine degraded organic waste matrix provided sufficient porosity for oxygen transfer and supported the growth of methanotrophs throughout 0.8 m depth of waste layer. Fluorescent in situ hybridization (FISH) analysis confirmed the presence of methanotrophs and their population was found varied along waste depth.