In biofiltration
the transformation of the organic material present
in the waste water is carried out by populations
of bacteria that stick to the granulated support
and they colonise it. So, the filtering
medium fills gradually owing to two factors,
the generation of a biological film on the surface
of the support and the retention of the suspended
solids. The excess biomass must be eliminated periodically
from the system so that the treatment capacity is
maintained. This operation is carried out with an
air and water wash.
Therefore the high level of treatment obtained using
biofiltration technology demands, a high concentration
of active biomass in the reactor and an optimisation
of the washing cycles to regularly eliminate the
excess biomass.
Below we have prepared a flow chart of the biofilters
in the treatment phase and in washing phase.
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