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market-farming - Re: [Market-farming] compost my septic sludge?

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  • From: Leslie Moyer <unschooler AT lrec.org>
  • To: Nan Hildreth <NanHildreth AT riseup.net>
  • Cc: Market Farming <market-farming AT lists.ibiblio.org>
  • Subject: Re: [Market-farming] compost my septic sludge?
  • Date: Fri, 18 Jun 2010 15:02:47 -0500

On 6/18/10 1:29 PM, Nan Hildreth wrote:
20100618184245.AA044C731 AT swift.riseup.net" type="cite">Thanks.

Yes, anaerobic rot, bad rot, in the septic tank confused me.  A host of anaerobic critters.  Are all anaerobes tiny bacteria?  Don't bigger critters like worms require air?
I don't know how big anaerobic critters are--my guess is they come in various sizes. I know there are aquatic worms, but I assume they derive oxygen from the water, but I don't know for sure. 

Once you bring sewage above ground, you expose it to air and, thus aerobic organisms, hence my suggestion to re-compost at sufficient composting temperatures above ground.  In areas with clay soils (& limited soil percolation) they spray septic deposits at night over the top of the ground to aerate them.  It is one of the 3 DEQ (Department of Environmental Quality) approved methods of sewage disposal in my state, for those not connected to a public sewer line.  (The other 2 being anaerobic septic system and "approved constructed wetland").  The lushest (ornamental) garden I ever had was built over a neighbor's poorly-functioning septic leach field. The phosphates (from most soaps) and nitrogen (from urine) present in septic runoff are great nutrients for plants.

Have you considered asking a septic pumping company what they do with wastes that they pump out and haul away?  I would be curious....  It might give you some direction.

My local (nearest city) municipal waste treatment plant sells composted (human) sewage (mixed with lots of wood chips). It is "EPA approved for agricultural use", so the statement that "all 50 states" disallow for food that will be resold seems like it couldn't be accurate.  I don't know much about their composting process, though I've seen the plant.  They have long windrows of raw sewage mixed with woodchips in various stages of composting ("most stinky" to "least stinky"). I know other cities do this, too.

When I think about all of the things that people *do* put on their fields (herbicides, pesticides, chemical fertilizers, etc.), composted septic wastes seem rather innocuous.  Yes, I understand about human pathogens....but most human pathogens are pretty fragile outside of the human body host--it's the reason the human race has existed this long--and if you're a healthy human being and you properly compost the waste, then I don't think there's a reasonable risk. 

William McDonough (Architect & author: Cradle To Cradle: Remaking he Way We Make Things) says that in nature "waste=food".  That is, that nature has a closed nutrient cycle.  Leaves fall to the ground and rot and the organisms in the soil recycle the nutrients in them and turn them back into soil nutrients for the tree.  (A little simplistic, but generally true.)  As humans, we've greatly disrupted that nutrient cycle.  We take, take, take from the land. Even responsible farmers, when we give back to the land, so very often it is still brought in from great distances.  It's not natural....it's not a nutrient cycle anymore.  Human "waste" is a resource that needn't be "wasted". 

I still don't know the answer to your question, Nan.  If it were me, I would certainly consider pulling it out to compost it and monitor the temperatures on it and just *see* what it does.  Then decide about whether to put it on your berries.  You could even send it off to be analyzed--it's cheap and easy to test for things like e-coli and that would be an indicator of other bacteria. (I have a DIY kit here at home that tests for e-coli and other coliform bacteria for $5. I use it for stream quality monitoring that I do for the state water quality organization.) 

--Leslie





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