Re: [compost_tea] Re: Flow rate for air pumps

From: <soilfoodweb_at_aol.com>
Date: Fri, 18 Feb 2005 15:33:23 EST

 
Instead of trying to confuse people, why not put in an explanation of what
you are doing in these examples?

 
Values of dissolved oxygen involve both temperature and air pressure. As
temperature rises, air, or water, cannot hold as much oxygen.
 
As air pressure decreases, air or water cannot hold as much oxygen.
 
At high enough elevation and high enough temperature, aeration rates have to
be rapid and constant in order to maintain aerobic conditions.
 
At a mile high in Denver CO, in the hot temperatures of mid-summer, fish
kill in shallow lakes happens because of the lack of oxygen in the water.
 
People have difficulty breathing when it gets extremely hot, and/or they are
at high elevation.
 
Making compost tea at high elevations in the middle of the summer when
temperatures are above 100 degrees means that with significant growth of the
organisms, the tea drops into reduced oxygen conditions, and starts losing the
beneficial fungi, protozoa and nematodes. A great deal of care is necessary to
maintain aeration, and keep growth of the organisms to a low enough level not
to go over the threshold.
 
There have been people solving this problem, but the systems they have
developed are for them to talk about. They lurk on this list........
 
Elaine
 
-------------------------------------------

---Using the spread sheet available from American Fisheries Society,
http://www.fisheries.org/html/publications/epubs/fhm2e/appendices.shtm
l
Maximum DO mg/liter in Carson Valley Nevada at 75F would be 7.09, at
80F 6.73 mg/liter
How then is DO maintained at a level no lower than 6? Since it
obviously cannot be, does this lower the quality of the ACT?

Using http://water.usgs.gov/owq/FieldManual/Chapter6/table6.2_6.html
tables,
With an atmospheric pressure of 643 mm Hg and 24C 7.2 mg/liter is
saturation.

It would seem any activity would take the DO levels to a level below
the aerobic threshold.











Received on Fri Feb 18 2005 - 16:31:50 EST

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