The Open Waste Management Journal

2015, 8 : 12-20
Published online 2015 July 10. DOI: 10.2174/1876400201508010012
Publisher ID: TOWMJ-8-12

Approximate Estimation of Landfill Emissions Considering Methane Oxidation

João Manoel Losada Moreira , Elissando Rocha da Silva and Giovano Candiani
Centro de Engenharia, Modelagem e Ciências Sociais Aplicadas, Universidade Federal do ABC, Av. dos Estados 5001, bloco B, sala 915, 09210-580 Santo André, SP, Brazil.

ABSTRACT

An approximate analytical scheme is presented to estimate landfill methane emissions taking into account the oxidation that occurs in the soil cover. To facilitate the solution of the methane transport equation we introduce a region dependent coefficient to account for the methane oxidation. Expressions for the distribution of methane concentration and methane flux inside the landfill and cover regions are obtained. The approach was applied to the CTVA-Caieiras landfill which was modeled as a vertical one-dimensional landfill with homogenous solid waste and soil cover regions. The methane emission obtained for the landfill was 2x10-5 mol m-2s-1 for a 4 year old deposited waste with a 0.5 m soil cover. The calculation compared well with the median of 11 field measurements conducted at the CTVA-Caieiras. The emission rates were strongly dependent on the oxidation coefficient utilized, which varies with the cover material and microclimate conditions of the site. The oxidation coefficient can be interpreted as the probability per unit of time of methane oxidation in the medium. The scheme provides a qualitative description of the methane transport and oxidation phenomena in landfills.

Keywords:

Biogas, emission, Landfill cover, methane, oxidation, oxidation coefficient.