All gas production data at the different temperatures are
represented as the dry gas production at STP to eliminate
the effects of water vapor pressure (Eq. (2)). The results
from the batch experiments are summarized in Table 2.
The influence of the digestion temperatures and feed loads
on the methane yields is shown in Fig. 2. Regardless of the
digestion temperature, increasing the feed load from 5% to
40% decreased the biogas yield, as would be expected due
to the incomplete degradation for 20 days. In Fig. 2, even
though the methane yields were different according to
tested temperatures, the slope of the graph does not clearly
vary within the range of feed loads from 5 to 20% at all
tested temperatures. Meanwhile, with a 40% feed load,
the methane yields were significantly lower (approximately
54% reduction) than with the lower feed loads regardless of