Biodisc
System -
The
biodisc
system
or
rotating
biological
contactor
is
a
more
advanced
type
of
aerobic
film
flow
treatment
system.
Here,
closely
spaced
discs,
usually
made
of
plastic
are
rotated
in
a
trough
containing
the
sewage
effluent.
The
discs
are
partially
submerged
and
become
coated
with
a
microbial
slime
similar
to
that
developing
in
trickling
filters.
Continuous
rotation
of
the
discs
keeps
the
slime
well
aerated
and
in
contact
with
the
sewage.
Microbial
growth
on
the
disc
surfaces
is
sloughed
off
gradually
and
removed
by
subsequent
settling.
