AvaliaÃÃo da retenÃÃo de gases em camadas de cobertura de aterros de resÃduos sÃlidos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Municipal solid waste landfills final covers work as a seal interface between the wastese and the external environment. This sealing layer is also responsible to avoid the infiltration of water into the waste mass and the emission of gases to the atmosphere. These interventions show by they own how important are both project and execution of the top cover as element of the landfill. This project aims at evaluations the relation between soil behavior and gases retention on the final cover of the Municipal Solid Waste Landfill of Aguazinha-PE. It evaluates geotechnical characteristics of the soil (soil classification, fines percentage, air permeability, compaction degree, saturation degree and water content), as well as the thickness of the layer and gas pressure in the interface soil-garbage. Nineteen static fluxbox tests were undertaken as well as measurements of pressure and gases concentration on the interface soil-garbage, measurement of the soil layer thickness and classification in each point, water and air permeability of the soil from each point that the flux-box test was taken. Gases emission were also evaluated on the Landfill drains and compared to emissions through the top cover. Field tests were undertaken between March 2006 and November 2007. A total of 315 tests were taken on field and laboratory. The soil used on the top cover of the cell was clayey sand and sandy clay, the thickness varied from 0.2 to 0.7m and the compaction degree of the soil varied between 76 and 104%. It points that during the top layer execution there was no topographic neither compaction control. The soil saturation degree varied from 8 to 74%. Air permeability tests showed that a saturation degree over 65% influences the gasses flux through the top cover. Results showed that CH4 emissions to the atmosphere are hugely influenced by the compaction degree and pressures on the soil-garbage interface. The thickness of the top layer didnât represent any direct relation to the decrease of emissions. It becomes a secondary factor when compared to the compaction degree of the soil, to the interface pressures and to soils degree of saturation. The final cover was responsible for about 22% of total CH4 emissions to the atmosphere. It represents environmental damages besides economical losses

ASSUNTO(S)

camadas de cobertura fluxo de gases gases flux gases retention caracterÃsticas e parÃmetros geotÃcnicos aterro de resÃduos sÃlidos urbanos retenÃÃo de gases geotechnical characteristics and parameters field and laboratory tests engenharia civil ensaios de campo e laboratÃrio municipal solid waste landfill top cover

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