Study on ammonia, methane, and odour emissions dynamics from pig slurry systems in an experimental chamber

Abstract

Agriculture is a major source of ammonia, methane, and odorants. Slurry management contributes significantly to their emissions and understanding the release mechanism of these gaseous compounds is essential for developing effective mitigation strategies. To identify key factors governing ammonia, methane, and slurry odorant emissions under controlled conditions, we developed an experimental chamber with partially slatted floor. The study includes simultaneous increases in slurry surface area and volume, increases in volume alone, setting different ventilation rates, and the effects of fouling. Ammonia emissions were significantly influenced by the simultaneous increase in both surface area and volume, by the ventilation rate and by the application of fouling. Methane emissions were significantly affected by the simultaneous increase in both surface area and volume, as well as the increase in volume alone, while ventilation rate or fouling had no significant effect on emissions. The dominant odorants emerging from slurry in terms of odour activity value were 3-methyl-1H-indole, 4-methylphenol, and hydrogen sulphide. Hydrogen sulphide exhibited emission patterns similar to methane, while emission patterns of 4-methylphenol and 3-methyl-1H-indole were more comparable with those of ammonia. Our results indicate that mitigation strategies should focus on controlling the slurry surface area and preventing fouling to reduce ammonia and odour emissions whereas maintaining a low slurry volume limits methane and hydrogen sulphide emissions.