[USCC] FW: Re: Fecal Coliform testing issues

[frank]

Jennifer and composters,

Jennifer Appel wrote:

>Method A believes the following:
>
>Add a high nitrogen starter to the pile and heat it up to kill the
>pathogens.
>
>What this actually does is kill both the pathogens and the beneficial
>species.  (But this method is not looking for beneficial organisms only the
>removal of pathogens.)  When the pile cools the bad guys come back first.
>(About the time you send in the sample for testing.)  
>
>Because there was a synthetic starter used - the aerobic bacteria that eats
>pathogenic organisms WILL NOT start their function because the synthetic
>process is a chemical one and the biological process CAN NOT START until the
>chemical reaction has finished its process.
>
>One way for Method A to achieve an aerobic pathogen free status, is to
>inoculate the pile with the beneficial organisms after the pile cools to a
>temperature and aerobic status that can support your new organisms.
>
>Once this has been achieved, the biology will perform the nutrient cycling
>functions required to KEEP the pile aerobic and pathogen free.
>
>  
>
You make a good point. With windrow composting, as I see it, the hot 
part is killing all while at the same time the microbes in the cooler 
band on the outside are getting established. Then we turn it all over 
and it starts again. I don't think the pathogens (I'm not talking about 
the indicator FC) will get established, as you suggest, because the 
aerobic conditions common in the cooler parts of the pile are not to 
their liking. So I think this is a process of killing the spores of 
pathogens along with the vegetative phase and providing a place where 
the benificials will take over. But your point is well taken when in 
vessel or container composting. That kills off all and then readies the 
material for whatever gets a foothold. Being aerobic I still see it as 
unlikely a pathogen that normally lives in anaerobic conditions will 
take over. FC will along with all the other common microbes surrounding 
the pile, or on equipment that survived the process. All good reasons to 
test after the heat phase.

>Method B: (rarely used in large commercial composting operations)
>It is also possible to NOT USE a synthetic high nitrogen starter.  This is a
>bit more advanced.  This method requires microscope time to assess the
>organisms in the pile, then feed stocks that promote specific aerobic
>organism activity to mitigate pathogenic organisms are added in appropriate
>proportion to promote a fully functioning aerobic compost pile that can
>provide 2-3 tons of Nitrogen supply if all the biology is functioning
>correctly.
>
>The SECOND reason I see for why pathogens reestablish in a pile is because
>far too many compost operations OVER WATER the pile every 3rd day and thus
>de-oxygenate it!  Three steps forward and two steps back is a hard way to
>make a good product.  I understand the intent of the rules, however, most of
>the operations I have visited could make a better product in a shorter
>period of time if they just used LESS WATER in conjunction with negatively
>aerating the piles!!!  
>
>Moisture content and optimum temperature will vary depending on the location
>where the pile is made, type of feed stock, type of pathogen or beneficial
>organisms and the type of aeration method used... Minnesota composting is
>very different from South Texas composting with respect to temperature, time
>and moisture content - and to add to that - the type of raw materials used
>will require a different amount of water depending on the biological species
>requirement in the pile.  (MSW versus food residual vs. cotton burr,
>in-vessel, static, etc.)  
>
>ALL soil has 3 properties: chemical, physical and BIOLOGICAL!  The first two
>have enough science behind them to establish good composting practices and
>it would appear an opportune time to add the third element based on
>scientific data in order to achieve a smoother process.
>  
>
As I see it all this should happen, and will, after the heat phase. 
Because we can -not- count on it happening in the way we want due to so 
many variables (you point out many) and based on no 'lab prove method' 
we should not include this in the pathogen reduction program. As it is 
now we do include this in the program and it is giving us misleading 
results and preventing other stabilization processes from being used - 
like vermistabilization.

Frank.



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-- 
Frank Shields
Soil Control Lab
42 Hangar way
Watsonville, CA  95076
(831) 724-5422 tel
(831) 724-3188 fax
frank at compostlab.com
www.compostlab.com