RESEARCH ARTICLE


Approximate Estimation of Landfill Emissions Considering Methane Oxidation



João Manoel Losada Moreira*, 1, Elissando Rocha da Silva1, Giovano Candiani2
1 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
2 Essencis Soluções Ambientais SA, Rodovia dos Bandeirantes, km 33, Caixa postal 543, 07803-970 Franco da Rocha, SP, Brazil


© 2015 Moreira et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the 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; Tel: +551149960115; E-mail: joao.moreira@ufabc.edu.br


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.