[USCC] oxygen, reply to Edo McGowan

[John A. Crockett]

I totally agree with Edo on passively aerated windrows having oxygen levels 
crash, far below what will support massive populations of aerobic microbes, 
including fungi.

In January of 1996, I did my first oxygen depletion test, on a pile of horse 
manure & shavings, 8' high, 35' x 35', with a very simple and crude forced 
aeration system.   We monitored the oxygen & CO2 every five minutes, and 
when we turned off the blower, the oxygen level crashed from 19% down to 2% 
within 15 minutes.  Horse manure / shavings is a VERY porous feedstock. 
Instantly I realized that the thousands of hours that I had spent turning 
compost was clearly not providing significant oxygen, and that full time 
forced aeration is essential to responsible composting, so that the microbes 
are not limited by lack of oxygen.

Shortly thereafter I started doing cross section profile oxygen CO2 & 
temperature monitoring of passively aerated windrows, including at other 
sites; and the data consistently confirmed that full time forced aeration is 
essential.   Graphs representing some of that data are on our 
www.magicsoil.com website, and have been there since May of 1998, available 
to all of you. Our hands on research has shown that our oxygen and CO2 
meters don't believe that passive aeration by convection is any where near 
adequate, to provide the microbes with enough oxygen.   And I don't expect 
you to believe me... get your own oxygen & CO2 meters, and do your own cross 
section profile monitoring and find out for yourself, and please let me know 
if your data is much different than what is on our website.  Could you work 
effectively without oxygen?  You and I are forced aeration systems, with our 
diaphragm muscle contracting and expanding our lungs every minutes of our 
lives, and if that system fails, we die.  Sure, there are essential details 
involved in designing efficient systems, we've learned from over ten years 
of hands on experience working with forced aeration, and our knowledge is 
based on real world experience.

More recent research using my compost research silos, some of which are 
configured to enable quantifying the volume of  air being moved through the 
compost, consistently show that in early stage compost we frequently need to 
provide a volume of fresh air over 23 times the volume of the compost, every 
hour.  By using Negative pressure (vacuum) on the newer compost, pulling the 
air through the newer compost, and then pushing that same air through older 
compost, the older compost very effectively serves as a bio-filter, 
capturing the nitrogen from the ammonia, and sulfur, and other nutrients, so 
the are in the finished compost.  Every time we've assayed over 3 billion 
active bacteria, per gram, dry weight, the CO2 level was below 4%, which 
means the oxygen level was 17% or higher.

Working together to Create a Sustainable Environment,

John Crockett, a.k.a. Dr. Mike Robe
Mother Nature's Farms, Inc
jac at magicsoil.com
www.magicsoil.com