Bio-oxidation of Escape Methane from Landfill Using Leachate-Modified Aged Refuse

A landfill bio-cover material for methane bio-oxidation was explored using aged refuse coupled with leachate. It was found that the aged refuse taken from an 8-year landfill could be used for the bio-oxidation of methane generated from landfill; moreover, the bio-oxidation ability was further enhanced in the presence of leachate. The highest methane oxidation capacity of 390 g CH4/(m(2) day) was obtained for the aged refuse modified with the leachate from aged-refuse bio-filter, close to the performance of compost. Leachate with extremely high organic matter content, however, was unfavorable for the growth of methane bio-oxidation Methanotrophs in aged refuse presumably because of oxygen consumption during organic matter degradation process. Thus, the recommended properties of leachate should be as follows: NH4+-N < 2500 mg/L, NO3--N 700-1800 mg/L, and COD > 500 mg/L. In addition, the organic matter and water contents in aged refuse after modified by leachate need to be controlled at 15.0-18.0 and 31.4-32.1%, respectively, for the purpose of efficient Methanotrophs metabolisms. Practical use of this novel bio-cover in real landfills cannot only control greenhouse gas emission, but promote the recycle and reuse of aged refuse, and simultaneous high-strength leachate treatment.