Fugitive Methane Emissions From Two Experimental Biocovers Constructed With Tropical Residual Soils: Field Study Using a Large Flux Chamber

Abstract

This study aimed at assessing the response of two experimental passive methane oxidation biocovers (PMOB) installed in a Brazilian landfill located in Guarapuava, State of Paraná. The PMOBs covered an area of 18 m² each, and were 0.70-m-thick. The first PMOB (control subarea) was constructed using the same soil used to cover closed landfill cells, i.e. a typical residual soil. The second PMOB (enriched subarea) was constructed with a mixture of the residual soil and mature compost, with a resulting organic matter content equal to 4.5%. CH 4 and CO 2 surface fluxes were measured in a relatively large (4.5 m²) static chamber. CH 4 , CO 2 and O 2 concentrations were also measured at different depths (0.10, 0.20, 0.25 and 0.30 m) within PMOBs. The concentrations from the raw biogas were also measured. Methane oxidation efficiencies (Eff ox) were estimated based on the CO 2 /CH 4 ratio. The average CH 4 and CO 2 concentrations in the raw biogas (42% and 32%, respectively) for the 16 campaigns corroborated those typically found in Brazilian landfills. Lower CH 4 fluxes were obtained within the enriched subarea (average of 20 g.m-2 .d-1), while the fluxes in the control subarea averaged 34 g.m-2 .d-1. Eff ox values averaged 42% for the control subarea and 80% for the enriched one. The results indicate that there is a great potential to reduce landfill gas (LFG) emissions by using passive methane oxidation biosystems composed of enriched substrates (with a higher content of organic matter).

Methane oxidation biosystem in landfill fugitive emissions using conventional cover soil and compost as alternative substrate—a field study

“…The average raw biogas composition was 37.7% (±5.5) methane and 26.9% (±1.7) carbon dioxide. Similar results were obtained by Franqueto et al (2019) in a 4-year-old cell in the same land ll (Guarapuava, Brazil).…”

“…Lee et al (2018) employed the pilot-scale biocover with land ll cover soil, perlite, earthworm cast, and MSW compost, at a 6:2:1:1 ratio, respectively, and obtained a 35-43% methane removal e ciency during the winter; while in the summer, this e ciency increased to 86-96%. Franqueto et al (2019) evaluated two experimental passive methane oxidation biosystems (PMOB's): an enriched subarea (using compost to obtain an organic matter content equal to 4.5% at the top of the cover layer) and a control subarea (using original land ll cover soil, with an organic matter content equal to 0.4%). They observed a higher methane oxidation e ciency in the enriched surface subarea (80%) when compared to the control (42%).…”

“…It seems relevant to highlight that great part of the eld studies employing biosystems to methane reduction in cover layers are performed in temperate climate countries and, therefore, in ambient conditions completely different than those observed in warm climate countries like Brazil. In addition, the implementation of biotic-systems in land lls without any type of biogas collection becomes a great challenge, since fugitive emissions by the cover layer tend to become even greater when compared to land lls that have some biogas collection system (Franqueto et al 2019).…”

Biofiltração De Metano Em Biogás De Aterro Sanitário: Um Estudo De Campo

“…Aterros sanitários são, reconhecidamente, uma das principais fontes antropogênicas de gases de efeito estufa (GEE) para a atmosfera. Nestas plantas, sistemas de coleta de biogás para aproveitamento energético constituem-se uma importante estratégia de controle de emissões de GEE (Duan et al, 2022;Franqueto et al, 2019;Kaza et al, 2018;Sadasivam e Reddy, 2014). Entretanto, mesmo em aterros de grande porte que possuem algum sistema de extração e aproveitamento energético, boa parte do biogás gerado nas células do aterro escapa pela camada de cobertura na forma de emissões fugitivas.…”

“…A capacidade de oxidação de metano pela população metanotrófica presente na camada de cobertura do aterro tem sido objeto de estudo de diversos trabalhos (Brandt et al, 2016;Cabral et al, 2010;Franqueto et al, 2019;Kjeld, 2013;Lee et al, 2018;Mei et al, 2015;Ndanga et al, 2015;etc.). Nesse contexto, vários parâmetros do processo de bio-oxidação devem ser observados de modo a otimizar a atividade metanotrófica, como temperatura, umidade do meio, etc.…”