Why is the pH rising in my nitrifying bioreactor?
K N and P J Harris
ecoli at cix.compulink.co.uk
Sat Mar 6 07:25:27 EST 1999
I suspect that the problem is air stripping of "excess" carbonate for
the high level of calcium carbonate you report. Nitrifiers always (in my
experience) take a while to get going. The system WILL acidify but only
when the population has built up to a fully functional level.
Try running the medium in a chemostat without organisms and see how the
pH behaves in relation to various air stripping rates.
We had a problem here at Reading many years ago with a cattle slurry
effluent system which was aerated but to which we added the slurry
effluent too quickly. The ammonia raised the pH so quickly (before the
nitrifiers "got going") that we had the classic ammonia toxicity effect
and were producing an effluent with 400 ppm nitrite-N for our local
river ! NOT a good idea.
Dr Peter Harris,
AKA <P.J.Harris at reading.ac.uk>
Department of Soil Science ,
The University of Reading,
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