Biofiltration of methane from cow barns: Effects of climatic conditions and packing bed media acclimatization

Abstract

The performance of biofiltration to mitigate CH4 emissions from cow barns was investigated in the laboratory using two flow-through columns constructed with an acclimatized packed bed media composed of inexpensive materials and readily available in an agricultural context. The biofilters were fed with artificial exhaust gas at a constant rate of 0.036 m 3 h-1 and low inlet CH4 concentration (0.22 g m-3 = 300 ppm). The empty-bed residence time (EBRT) was equal to 0.21 h. Additionally, in order to simulate temperature changes under natural conditions and determine the influence of such cycles on CH4 removal efficiency, the upper part of the biofilters were submitted to temperature oscillations over time. The maximum oxidation rate (1.68 μg CH4 gdw-1 h-1) was obtained with the commercial compost mixed with straw. Accordingly, it was considered as packing bed media for the biofilters. The CH4 removal efficiency was affected by the temperature prevailing within the biofilters, by the way in which the cooling-warming cycles were applied and by the acclimatization process. The shorter the cooling-warming cycles, the more oxidation rates varied. With longer cycles, CH4 removal rates stabilized and CH4 removal efficiencies attained nearly 100% in both biofilters, and remained at this level for more than 100 days, irrespective of the temperature at the top of the biofilter, which was-at times-adverse for microbiological activity. The first order rate constant for CH4 oxidation kinetics of the entire system was estimated at 15 h-1. If such rate could be transposed to real field conditions in Canada, home to nearly 945,000 dairy cows, biofiltration may be applied to efficiently abate between 2 x 10 6 and 3 x 10 6 t yr-1 of CO2 equivalent (depending on how estimates are performed) from bovine enteric fermentation alone.

Greenhouse Gas Emissions From Biofilters for Composting Exhaust Ammonia Removal

“… Lim et al (2012) reported the CH 4 reductions ranged from 0.1% to 1.9% in biofilters with 0.3s–0.6s EBRT. Fedrizzi et al (2018) attained nearly 100% CH 4 100% removal efficiencies with 756s EBRT, so enough EBRT is needed for CH 4 removal. Akdeniz et al (2011) achieved the removal efficiencies of 6.9%–25% for CH 4 by using the pilot-scale biofilters with lava rock media at the high moisture levels and low inlet CH 4 concentrations (90% moisture content and average of 31.0 ppm of inlet CH 4 concentration), while the EBRT was just 5s.…”

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

“…Entretanto, assim como ocorreu com a umidade, essa grande variação de temperatura também não perturbou as eficiências de oxidação de metano (r=0.24; p=0.54 para controle com T1; r=0.25; p=0.50 para melhorada com T1 e r=-0.25; p<0.49 para controle com T2 e r=-0.26 e p=0.49 para melhorada com T2). Muitos trabalhos têm reportado uma forte dependência da eficiência de oxidação de metano com a temperatura do meio (Capanema e Cabral, 2012;Fedrizzi et al, 2018;Lee et al, 2018;Scheutz et al, 2009). A população metanotrófica, de características mesofílicas, preferem ambientes com temperaturas na faixa de 20 a 37°C (Humer e Lechner, 1999), 25 a 35°C (Park et al, 2009;Scheutz et al, 2009) ou 30°C (Spokas e Bogner, 2011).…”

“…As amostras de gás eram coletadas a partir dos pontos superior (gás tratado, no "headspace" do leito) e inferior (biogás bruto) das colunas (Figura 1). Desse modo, foi possível avaliar a performance das colunas melhorada e controle no que se refere à eficiência global de oxidação de metano (Equação 1) (Fedrizzi et al, 2018;Huang et al, 2011): Para a avaliação do perfil vertical de oxidação de metano ao longo dos leitos filtrantes, as amostras foram retiradas de seis pontos de amostragem: superior ("headspace"), inferior (biogás bruto) e mais quatro pontos centrais, em contato direto com os leitos (Figura 1). Neste caso, foram determinadas as concentrações de metano e oxigênio do ponto amostrado.…”

Effect of Cubicle Hood System on Methane Concentrations Around the Lying Area in Cold Climate Dairy Cattle Buildings

“…Likewise, pilot studies indicate biofiltration as a potential low-cost CH 4 abatement technique in the livestock sector (Fedrizzi et al, 2018, Oliver and Schilling, 2016, Melse and Van Der Werf, 2005. This is because, in contrast to catalytic CH 4 treatment, which require complex combustion units with higher operating temperatures (> 400 • C) and inlet CH 4 concentrations (> 5000 ppm) to effectively function (He et al, 2020), biofiltration systems are easier to design and can function at ambient temperature (< 30 • C), atmospheric pressure, and relatively low inlet CH 4 concentrations (Melse and Hol, 2017).…”