Data relating to the content of specific groups of organic substances
(Table 5) indicate that the three mixtures were characterised
by different contents of carbohydrates and lipids. In particular
within the group of carbohydrates, the starch content changes
according to the waste composition, while other carbohydrates
as cellulose, hemicellulose, lignin or simple sugars were found to
be almost constant. This effect may be related to the constant content
of the fractions F and V while the changes in BP fraction
affected not only total carbohydrate content, but also particularly
starch content. Protein content was slightly higher in Mix B,
although still similar to the other two fractions. This indicates that
in all three mixtures, the same nutrients were available for biological
degradation, and thus differences in fermentative process are
mainly associated to the type of organics available.
The average cumulative hydrogen and methane productions
obtained from the three mixtures Mix A, Mix B and Mix C under
the tested experimental conditions are reported in Table 6. Eq.
(2) produced the best fitting mathematical model for the experi-