3.3. Biomass characterization and sludge production
At the end of the experimental period, biomass concentration in
the bed was evaluated on samples taken at three different heights
of the bed to check the possible presence of a stratified distribution
owing to the up-flow functioning of the reactor. Biomass was
instead quite uniformly distributed with a concentration of
23 kgVSS m3
bed.
Quite small granules with diameter around 0.5 mm were
partiallyembedded in the biofilm, but easily visible to the naked eye.
Even if no differences in concentration were observed, the effect
of the up-flow operation impacted the settling ability of the sludge.l