[USCC] Oxy6gen requirements for composting bio-solids

[kuter.agresource@verizon.net]

Basic research on biosolids composting has been peformed by the Beltsville group and  Mel Finstein at Rutgers. Those of us who have been around long enough remember the heated "discussions" when Dr. Finstein had the floor at numerous conferences.  You will note that Finstein advocated higher rates of aeration, not to provide O2, but to maintain temperatures at levels to optimize microbial activity. 
Haug's book on compost engineering provides a good review of this issue and Keeners work at OSU also provides basic engineering principles around aeration. 

  

>From: "John A. Crockett" <jac at magicsoil.com>
>Date: 2007/06/03 Sun PM 02:03:16 CDT
>To: "U.S. Composting Council listserve" <compost at mailman.cloudnet.com>
>Subject: [USCC] Oxy6gen requirements for composting bio-solids

>Join us at the US Composting Council's 16th Annual Conference & Trade Show
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>
>Over the past nine days we've done some preliminary research on composting
>bio-solids.   We blended in a shredder a bulking material other than wood
>shavings, which gave us a nice texture, moisture content of about 53%.
>While I had been told that 500cfh / dry ton, excluding bulking agent was
>enough air, including the material we used to correct the moisture content
>and we believe, provide a readily available source of carbon, the average of
>12 air flow tests has been 2,222cfh, per dry ton of compost; 16.3 times the
>volume of the compost, in fresh air every hour.  That is to yield CO2 in the
>off-gas between 1 - 2%.  Other research that we've done suggests that CO2
>over 4% significantly suppresses the population of active bacteria.
>
>We're generally using vacuum of about 0.25"wc to pull the air through the
>compost.  Daily turning seems to be important when dealing with particle
>size of less than ¼".  As of 7 days ago the moisture content was 53%.
>Samples taken this morning after turning the compost, are in the drying oven
>now and we'll have that data by tomorrow morning. 
>
>We're questioning what affects higher pile depth will have on the aeration
>and will research that in the course of time.
>
>Is our research methodology flawed, or is it possible that the 500cfh / dry
>ton, is flawed, regardless of the source of that belief? Granted, our sample
>size is only 4.18 - 6.4 cubic feet.  
>
>We have no incentive to publish in peer reviewed journals.  When I did a
>Google search a few days ago for "compost research silos" our work came up
>four out of the top four search results.  Doesn't anyone else recognize the
>value of R&D, and the cost of relying on popular beliefs that may not be
>good process technology?
>
>In the meantime, we'd like to network with others who are really interested
>in improving the efficiency of the composting process.  Contact information
>is below.
>
>Working Together to Create a Sustainable Environment,
>John A. Crockett, a.k.a. Dr. Mike Robe
>Mother Nature's Farms, Inc.
>(845) 225-7763
>http://www.magicsoil.com/
>jac at magicsoil.com
>Â 
>
>
>
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