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

Wang K, Li W, Li X, Ren N - Sci Rep (2015)

Bottom Line: 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.These founding provided a new insight toward "aerobic" composting process and a sound foundation for the development of efficient composting technology.

View Article: PubMed Central - PubMed

Affiliation: School of Municipal and Environmental Engineering, State Key Laboratory of Urban Water Resource and Environment (SKLUWER), Harbin Institute of Technology, 73 Huanghe road, Harbin, Heilongjiang 150090, China.

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.

No MeSH data available.


Related in: MedlinePlus

The microprofiles of DO, ORP,  and and the aerobic-anoxic dual structure in the chicken manure during active composting.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4595641&req=5

f6: The microprofiles of DO, ORP, and and the aerobic-anoxic dual structure in the chicken manure during active composting.

Mentions: It is commonly known that organic mineralization rate under the aerobic condition is essentially faster than that under anoxic condition. The aerobic metabolism in the surface layer released more respiration heat, which increased the temperature of the composting system and substantially improved organic hydrolysis rate and anoxic metabolism efficiency in the internal zone. A portion of soluble substrate hydrolyzed in the anaerobic core possible diffused and was oxidized in the surface aerobic layer38. As a result, oxygen penetration was limited to the surface layer of the manure particles due to microbial oxygen utilization during the active stage. Oxygen diffusion efficiency in the manures cannot be directly improved though increasing aeration rate. Hence, the aerobic-anoxic dual structure has a long duration inside the manure particles during the active stage even under a high aeration rate (Fig. 6). The low DO level limits the organic mineralization rate in the anoxic zone. Therefore, the high ratio of anoxic zone in the manure particle could be one of the major reasons leading to the long treatment period required for active composting.


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

Wang K, Li W, Li X, Ren N - Sci Rep (2015)

The microprofiles of DO, ORP,  and and the aerobic-anoxic dual structure in the chicken manure during active composting.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595641&req=5

f6: The microprofiles of DO, ORP, and and the aerobic-anoxic dual structure in the chicken manure during active composting.
Mentions: It is commonly known that organic mineralization rate under the aerobic condition is essentially faster than that under anoxic condition. The aerobic metabolism in the surface layer released more respiration heat, which increased the temperature of the composting system and substantially improved organic hydrolysis rate and anoxic metabolism efficiency in the internal zone. A portion of soluble substrate hydrolyzed in the anaerobic core possible diffused and was oxidized in the surface aerobic layer38. As a result, oxygen penetration was limited to the surface layer of the manure particles due to microbial oxygen utilization during the active stage. Oxygen diffusion efficiency in the manures cannot be directly improved though increasing aeration rate. Hence, the aerobic-anoxic dual structure has a long duration inside the manure particles during the active stage even under a high aeration rate (Fig. 6). The low DO level limits the organic mineralization rate in the anoxic zone. Therefore, the high ratio of anoxic zone in the manure particle could be one of the major reasons leading to the long treatment period required for active composting.

Bottom Line: 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.These founding provided a new insight toward "aerobic" composting process and a sound foundation for the development of efficient composting technology.

View Article: PubMed Central - PubMed

Affiliation: School of Municipal and Environmental Engineering, State Key Laboratory of Urban Water Resource and Environment (SKLUWER), Harbin Institute of Technology, 73 Huanghe road, Harbin, Heilongjiang 150090, China.

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.

No MeSH data available.


Related in: MedlinePlus