Effect of aeration interval on oxygen consumption and GHG emission during pig manure composting.

To verify the optimal aeration interval for oxygen supply and consumption and investigate the effect of aeration interval on GHG emission, reactor-scale composting was conducted with different aeration intervals (0, 10, 30 and 50 min). Although O2 was sufficiently supplied during aeration period, it could be consumed to <10 vol% only when the aeration interval was 50 min, indicating that an aeration interval more than 50 min would be inadvisable. Compared to continuous aeration, reductions of the total CH4 and N2O emissions as well as the total GHG emission equivalent by 22.26-61.36%, 8.24-49.80% and 12.36-53.20%, respectively, was achieved through intermittent aeration. Specifically, both the total CH4 and N2O emissions as well as the total GHG emission equivalent were inversely proportional to the duration of aeration interval (R2 > 0.902), suggesting that lengthening the duration of aeration interval to some extent could effectively reduce GHG emission.