Effects of ventilation on aerobic composting of swine feces

With the use of corn straw and rice hull as bulking agents, an experiment was conducted to investigate the effects of ventilation on the aerobic composting of swine feces. Three kinds of ventilation(0.5, 0.3 and 0 m3/min) were designed for three treatments, and the time for aeration and alternation was regulated by different temperatures in central piles. The changes of temperature in piles, pH value, water content, content of organic substance, content of total nitrogen and ratio of carbon to nitrogen in composting material were measured. Results indicated that proper ventilation could enhance the temperature of piles and keep the high temperature for longer time, and control the rise of pH value in composting. It was beneficial to the degradation of organic substance and the drop of ratio of carbon to nitrogen in composting material, with the ventilation of 0.3 m3/min better than others. When the initial ratio of carbon to nitrogen in the composting material was 30︰1, and initial water content was 62%, the mixture of corn straw and rice hull was an effective bulking agent, which could improve the aeration status of composting material and reach the level of innocuity.