4. Conclusions
From experimental results here obtained the following conclusions
can be summarized:
The addition of vegetable wastes to semi-continuous anaerobic
digester treating swine manure had a positive effect on methane
production. The high buffer capacity of swine manure coupled
with the high carbon/nitrogen ratio supplied by vegetable
wastes improved process performance.
SEM pictures showed that lignin and cellulose were not completely
degraded at the end of the experimental time. Microbial
composition was found to change from long rod-shaped bacteria
to cocci and rods morphotypes after 120 d of anaerobic
digestion.
The novelty of this research regards SEM characterization of
anaerobic digestion sludges, which permitted us to obtain information
about spatial distribution and population changes of
bacterial morphotypes.