Wastwater Treatment-Total Kjeldahl Nitrogen vs NH4 nitrogen
Michael J. Chambers
nitrogen.
Also, what significance does either have on reducing BOD levels.
Thanks,
Mike
Charles N. Haas
mc...@uhura.cc.rochester.edu (Michael J. Chambers) wrote:
> Can someone describe for me the relationship between TKN and ammonia
> nitrogen.
>
Total Kjeldahl Nitrogen (TKN) includes all amino/amine/amide nitrogens,
such as organic amines, peptides, proteins, as well as inorganic ammonia.
Hence TKN is always >= ammonia nitrogen.
> Also, what significance does either have on reducing BOD levels.
>
The nitrogen groups included in TKN are all reduced (relative to aerobic
environments). Hence, there will be nitrogenous oxygen demand that may be
included in a total bod. However, the usual 5 day BOD (that is used for
regulatory purposes) generally does not include nitrogenous demand, so that
neither ammonia nitrogen nor TKN would be included.
In the environment, most TKN degrades through an intermediate ammonia
nitrogen stage.
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from the keyboard of: Charles N. Haas:LD Betz Professor of
Environmental Engineering
Drexel University:::Philadelphia, PA 19104
Haa...@Dunx1.ocs.drexel.edu
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Ping-Chik Richard Ng
>Can someone describe for me the relationship between TKN
nitrogens using a chemical test. That will include R3N, R2NH, RNH2,
and NH3 (or NH4OH). (There is no such thing as NH4, but NH4+ is
possible in acidic environment.)
>and ammonia nitrogen.
When you do a Ammonia test, you are testing ammonia. This can be done
using a probe and a meter.
>
>Also, what significance does either have on reducing BOD levels.
There are two type of BOD; CBOD (carbonaceous biochemical oxygen
demand) and NBOD (nitrogeous BOD). Usually the nitrification bacteria
are less abonden therefore the NBOD is not significant until the
eighth day of the BOD process, by that time most if the CBOD are
complete. When people mention BOD usually is BOD5, which is the CBNOD
after 5days of bacteria activities. You can calculate the BOD total
using a formula when you know the rate of activities and concentration
of your sample, but this do not include NBOD. The total BOD of the
sample will be the sum of both. Since nitrogen can be easily to
determine using chemical process therefore is not point to do a
complete BOD test (it can take as long as 20 or more days for the NBOD
to complete.).
>Thanks,
>Mike
You can find this information in "McGraw-Hill series in Water
Resources and Environmental Engineering", George Tchobanglous, Metcalf
and Eddy, Inc. Third Edition, 1991.
I hope that helps.
R.Ng