As shown in Table 3, the seven process parameters of all mixtures
studied were quite different. Both the acidification and composting
times covered a wide range. The hydrolysis reaction rates
for all mixtures could be assumed to be of the same magnitude,
since each mixture had the same amount of food waste and the
bulking agents were almost inert. The wide ranges of the composting
and acidification times indicated that physical property
changes caused by the bulking agents significantly affected the oxidation
reaction rates of composting mixtures.
The carbon contents in final products changed a little, but nitrogen
contents reduced significantly resulting in higher C/N ratios.
Same phenomenon was also found in our previous studies using
the same composter. (Chang et al., 2006; Chang and Hsu, 2008).
It was due to sufficient air supply and frequent agitation of the
composter.