Evaluation of stability and maturity during forced-aeration composting of chicken manure and sawdust at different C/N ratios.
We examined physicochemical and biological parameters in order to assess their effectiveness as stability and maturity indicators during the forced-aeration composting process of chicken manure mixed with different amounts of sawdust, yielding initial C/N ratios of 12, 18 and 28. The composting mixture with initial C/N ratio of 28 maintained the temperature exceeding 55 degrees C for more than 3d, but the period with temperature above 55 degrees C in the bottom layer of the composting mixtures with initial C/N ratios of 12 and 18 did not meet the requirement of pathogen destruction. The final electrical conductivity in three composting mixtures did not exceed the limit value of 3000microScm(-1) for stable composts. Only the final NH(4)(+)-N of composting mixture with an initial C/N ratio of 28 did not exceed the limit value of 400mgkg(-1) to be considered a stable compost. The NO(3)(-) content in the three composting mixtures increased with the composting time, and a more pronounced increase was found in the composting mixture with an initial C/N ratio of 28. The final specific oxygen uptake rate was 2.38, 2.35, 0.70mgh(-1)g(-1) organic matter for composting mixtures of initial C/N ratio of 12, 18 and 28, respectively, which suggested a higher stability in composting mixture of initial C/N ratio of 28. The final germination index in composting mixture of initial C/N ratio of 28 was 94%; however, the germination indices in the composting mixtures of initial C/N ratio of 12, 18 were never over 80%.
Gao
Mengchun
M
Ocean University of China, Qingdao, PR China. mengchungao@hotmail.com
Liang
Fangyuan
F
Yu
An
A
Li
Bing
B
Yang
Lijuan
L
D000818:Animals; D001420:Bacteria, Aerobic; D001673:Biodegradation, Environmental; D002645:Chickens; D006863:Hydrogen-Ion Concentration; D008372:Manure; D009566:Nitrates / Q000737:chemistry / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature; D014934:Wood
D008372:Manure; D009566:Nitrates; D000644:Quaternary Ammonium Compounds