Biomass concentration in the reactor was determined at
the end of the experimental campaign, detaching representative
samples of biomass (microbial samples) from three
heights of the microbial bed (top, medium and bottom). The
sampled bed volume was evaluated as the fraction of carrier
elements with respect to 1023, that is the number of carrier
elements per litre of bed. The sludge present on the removed
carriers was collected in a known volume of tap water, and
TSS and VSS were measured