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In Vitro Methane Removal by Volcanic Pumice Soil Biofilter Columns over One Year
Author(s) -
Pratt Chris,
Walcroft Adrian S.,
Tate Kevin R.,
Ross Des J.,
Roy Réal,
Reid Melissa Hills,
Veiga Patricia W.
Publication year - 2012
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2011.0179
Subject(s) - topsoil , soil water , environmental chemistry , chemistry , biofilter , moisture , environmental science , soil science , environmental engineering , organic chemistry
Soil methane (CH 4 ) biofilters, containing CH 4 –oxidizing bacteria (methanotrophs), are a promising technology for mitigating greenhouse gas emissions. However, little is known about long‐term biofilter performance. In this study, volcanic pumice topsoils (0–10 cm) and subsoils (10–50 cm) were tested for their ability to oxidize a range of CH 4 fluxes over 1 yr. The soils were sampled from an 8‐yr‐old and a 2‐yr‐old grassed landfill cover and from a nearby undisturbed pasture away from the influence of CH 4 generated by the decomposing refuse. Methane was passed through the soils in laboratory chambers with fluxes ranging from 0.5 g to 24 g CH 4 m −3 h −1 . All topsoils efficiently oxidized CH 4 . The undisturbed pasture topsoil exhibited the highest removal efficiency (24 g CH 4 m −3 h −1 ), indicating rapid activation of the methanotroph population to the high CH 4 fluxes. The subsoils were less efficient at oxidizing CH 4 than the topsoils, achieving a maximum rate oxidation rate of 7 g CH 4 m −3 h −1 . The topsoils exhibited higher porosities; moisture contents; surface areas; and total C, N, and available‐P concentrations than the subsoils, suggesting that these characteristics strongly influence growth and activity of the CH 4 –oxidizing bacteria. Soil pH values and available‐P levels gradually declined during the trial, indicating a need to monitor chemical parameters closely so that adjustments can be made when necessary. However, other key soil physicochemical parameters (moisture, total C, total N) increased over the course of the trial. This study showed that the selected topsoils were capable of continually sustaining high CH 4 removal rates over 1 yr, which is encouraging for the development of biofilters as a low‐maintenance greenhouse gas mitigation technology.