N ₂O reduction using goat and cow manure-based compost as biofilter medium

Nitrous oxide (N ₂O) is the fourth most prevalent greenhouse gas in the atmosphere after carbon dioxide (CO ₂), methane (CH ₄), and water vapor. This gas contributes most significantly to global warming since it decomposes with great difficulty in the atmosphere, even in low concentrations. Emissions of N ₂O gas are known to have an impact 310 times greater than the impact of CO ₂ on global warming. According to the Intergovernmental Panel on Climate Change, N ₂O concentration in the atmosphere has increased by 46 ppb (17%) since 1750, and continues to increase. A biofilter works by draining the contaminated air flow through a porous medium in which contaminants in the air flow are adsorbed by biofilms; these contaminants are then oxidized to produce biomass, CO ₂, H ₂O, nitrate (NO ₃ ^-), and sulfate (SO ₄ ^2-). In addition, the biofilter supports the growth of microorganisms present in the porous medium. This research was conducted to investigate the performance of two types of a compost-based filter medium in 9 hours N ₂O biofiltration, with N ₂O flow rate variations and variations in water content levels of the filter medium. A biofiltration experiment was conducted to evaluate the effects of selected parameters on N ₂O removal efficiency. The results showed that goat manure-based compost was more effective in reducing N ₂O compared with cow manure-based compost, with the highest efficiency of 70.1%.