Regulating aeration intensity to simultaneously improve humification and mitigate gaseous emissions in food waste digestate composting: Performance and bacterial dynamics

Abstract

This study assessed the impact of aeration intensity on food waste digestate composting to simultaneously govern organic humification and gaseous emissions. Results show that an augment in the aeration intensity from 0.1 to 0.4 L·kg−1 DM·min−1 provided more oxygen to facilitate organic consumption and thus temperature increase, but slightly restrained organic humification (e.g. less humus content and higher E4/E6 ratio) and substrate maturity (i.e. lower germination index). Furthermore, increasing aeration intensity inhibited the proliferation of the genera Tepidimicrobium and Caldicoprobacter to alleviate methane emission and enriched the genus Atopobium to boost hydrogen sulphide production. More importantly, increasing aeration intensity limited the growth of the genus Acinetobacter for nitrite/nitrogen respiration, but strengthened aerodynamics to blow out nitrous oxide and ammonia produced inside piles. Principal component analysis comprehensively indicated that a low aeration intensity of 0.1 L·kg−1DM·min−1 facilitated precursors synthesis toward humus and simultaneously mitigated gaseous emissions to improve food waste digestate composting.