Three different material, pine shaving, grass hay and wheat straw, have been used as substrate for swine manure composting. Substrate – manure mixes at 40, 32 and 28% dry matter were passively (ducts installed under the compost pile) and actively (2 ml of air/s per kg of original dry matter) aerated in duplicate during 21 days. The temperature measured in both aeration regimes gave similar values and reaches damaging temperatures (above 65 C) where the microbial activity stops. However more drying of the compost material was observed with the active aeration. The convective air flux seemed to be related to microbial activity and heat generation rather than the temperature differential between the compost and the ambient air. Further work is needed to better understand the phenomena that acting on the temperature.
Composting is a way to stabilize manure and to reduce odour emissions also. However in order to obtain a good quality compost, the temperature have to stay in a certain range between 55 to 65 C. No results show the compost composition after the 21 days but composting process is known to result in ammonia and nitrous oxide emissions which are detrimental to the environment.