BOD &
O2
Transfer
BOD is Biochemical
Oxygen Demand
and is the
amount of
Dissolved
Oxygen (DO)
consumed by
microorganisms
for the biochemical
oxidation
of organic
and inorganic
matter. This
is a five
day test that's
why it's a
lot of times
shown as BOD5.
Much has been
written about
BOD and by
going to any
wastewater
treatment
site on the
WEB, you can
find information
about BOD.
The BOD test
was developed
to predict
the effect
of wastewater
on receiving
streams and
to determine
their capacity
to assimilate
the organic
matter.
The mass
transfer of
oxygen in
water is a
complex issue
and a number
of researchers
have made
lifetime studies
of this one
theme. Reference
to oxygen
transfer by
bubbles could
be right in
some instances
mainly in
a fermenter
where protein
covers the
bubble surface.
That's why
in fermenters
they use impellers
and air injectors.
There are
formulas like
20 CFM of
air per 1,000
cubic feet
of water will
create a DO
of 1+ mg/L.
We have found
if you use
an air injector
such as a
Mazzei you
will have
excellent
mass transfer
at low horsepower.
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