The use of novel packing material for improving methane oxidation in biofilters

• Published in: Journal of environmental management 2016-11, Vol.182, p.412-420
• Main Authors: Brandt, Emanuel Manfred F., Duarte, Felipe V., Vieira, João Paulo R., Melo, Vinícius M., Souza, Cláudio L., Araújo, Juliana C., Chernicharo, Carlos Augusto L.
• Format: Article
• Language: English
• Subjects: Air Pollutants - metabolism; Aluminum Silicates; Biodegradation, Environmental; Biomass; Blast furnace slag; Diffuse emissions; Expanded vermiculite; Filters; Filtration - methods; Industrial Waste; Methane; Methane - metabolism; Methane biofiltration; Methanotrophs; Oxidation; Oxidation-Reduction; Plant Leaves; Polyethylene; Polyurethanes; Slag; Soil; Sponge
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2016.07.075

The use of biofilters (working bed volume of 7.85 L) for the oxidation of CH4 at low concentrations (from 0.17%v/v to 3.63%v/v, typically in waste gas from anaerobic sewage treatment) was investigated and four empty bed residence times were tested (in min): 42.8, 29.5, 19.6, and 7.4. Mixtures of organic (composted leaves) and three non-organic materials (sponge-based material - SBM, blast furnace slag - BFS, and expanded vermiculite - ExpV) were used as packing media. Along 188 operational days after the steady state was reached (95 days for start-up), the CH4 mineralization decreased while the inlet loads gradually increased from 3.0 ± 0.8 gCH4 m−3 h−1 to 148.8 ± 4.4 gCH4 m−3 h−1. The biofilter packed with ExpV showed the best results, since the CH4 conversions decreased from 95.0 ± 5.0% to 12.7 ± 3.7% as a function of inlet concentration, compared to the other two biofilters (SBM and BFS) which showed CH4 conversions decreasing from 56.0 ± 5.4% to 3.5 ± 1.2% as a function of inlet concentration. The methanotrophic activity of biomass taken from ExpV biofilter was three times higher than the activity of biomass from the other two biofilters. Taken together, these results suggested that ExpV provides an attractive environment for microbial growth, besides the mechanical resistance provided to the whole packing media, showing the potential to its use in biofiltration of diffuse CH4 emissions. •The oxidation of CH4 at low concentrations in three biofilters was investigated.•Mixtures of composted leaves and 3 non-organic materials were used as packing media.•Biofilters achieved theoretical CH4 mole conversion (steady-state) in 95 days.•Non-organic materials improved filter bed mechanical resistance and hydrodynamics.•Expanded vermiculite provides appropriate environment for methanotrophs enrichment.