Emissions of malodorous compounds and greenhouse gases from composting swine feces

Emissions of harmful gases, malodorous compounds and greenhouse gases emitted during composting of swine feces under continuous aeration were studied using a laboratory-scale composting apparatus. Concentrations of ammonia and sulfur compounds in the exhaust gas rose remarkably after starting and at every turning, and their changes reflected the odor concentrations calculated from sensory tests. Volatile fatty acids, in high concentrations at the start, were rapidly reduced within several hours from starting and did not rise again. Methane emission was observed within only 1 day from starting. Nitrous oxide repeatedly rose and fell after every turning, as did ammonia. From the viewpoint of nitrogen loss during composting, however, the total amount of nitrous oxide emission seemed quite small compared with that of ammonia.