Spatial nitrifications of microbial processes during composting of swine, cow and chicken manure

Abstract

Composting is a widely-used method to recycle the nutrients in livestock manure for agriculture. The spatial stratifications of microbial processes inside the manure particle that determine organic and nitrogen transformation are virtually unclear. Here, we show the evolution of the interior microenvironment of swine, cow and chicken manure by using microelectrodes during forced-aeration composting. Composting has generally been regarded as an aerobic bioprocess, however, the long-existing of a large anoxic zone inside these manures was confirmed during the active phase in this study. The profile of the oxidation–reduction potential dramatically decreased first and then gradually increased. The spatial difference in the ammonia concentration was not significant, but nitrate concentration continuously decreased with depth. The anoxic condition within the manure particle was demonstrated to be a primary cause of the severe ammonia emission and the long composting period. These founding provided a new insight toward “aerobic” composting process and a sound foundation for the development of efficient composting technology.

Diet Supplementation With Pomegranate Peel Extract Altered Odorants Emission From Fresh and Incubated Calves' Feces

“…It was noted by Brinton (2006) that microorganisms producing VFAs under semi-anaerobic conditions are facultative microorganisms and hence, events of oxygen replenishment will not necessarily disturb their presence; moreover, VFAs produced serve as an energy source for consequent aerobic microbial activity, once favorable aerobic conditions return. Depending on aerobic degradation rates (and hence oxygen utilization rate), it was shown that oxygen diffusion is limited to a range of several hundred micrometers around manure particles and thus a substantial portion remains anaerobic even in well aerated systems (Wang et al, 2015). The peak of VFAs shown in the present work is related to the most active degradation phase during which it is most difficult to sufficiently maintain aerobic conditions within aggregates and micro-environments.…”

Efecto de la incorporación de pasto estrella sobre el mejoramiento del proceso y la calidad del producto del compostaje de biorresiduos

“…Conforme la MO fue degradada, se observó un incremento gradual del pH, pasando de ligeramente ácido a alcalino (valores entre 8.0 y 9.5 unidades). Autores como Wang et al, (2015) y Cáceres et al, (2018) atribuyen este comportamiento a la mineralización de compuestos ricos en NT (i.e proteínas, aminoácidos y péptidos) y a nitrógeno amoniacal producido durante el proceso de amonificación. Efecto de la incorporación de pasto estrella sobre el mejoramiento del proceso y la calidad del producto del compostaje de biorresiduos…”

Effects of carbon-based additives and ventilation rate on nitrogen loss and microbial community during chicken manure composting

“…Aerobic composting shows potential for the conversion of the chicken manure into biofertilizers and reduce the potential pollution [3,4]. Whereas the characteristics of poor porosity and low C/N ratio, limit the oxygen consumption and organic matter (OM) degradation, resulting in high nitrogen loss during chicken manure composting [5]. However, the high temperature (>45˚C) reached during the composting process may help to shift the NH 4 to NH 3 [6,7] and inhibit nitrification at the same time, thereby increasing NH 3 volatilization [8].…”