bob day wrote: If you know of other data that shows worms can destroy disease and parasites in human waste the way a hot compost method does, please publish the link.
jacque greenleaf wrote:Warning, large copy pasta.
From the current issue of Worm Farming Secrets
(subscribe here http://www.wormfarmingsecrets.com/ )
"Can worms spread harmful bacteria such as ecoli and salmonella?"
~ Shauna Babcock
That is a really good question!
Worms themselves are not hosts for pathogens, but the materials
they live in and consume CAN contain various disease-causing
organisms. Thus caution is certainly warranted when using
materials such as manure and sewage sludge, which can both
contain high levels of pathogens.
Not only are worms not pathogen-infested organisms, but there is
actually a growing body of evidence to suggest that worms
(specifically composting worms) can actually significantly reduce
populations of pathogens in waste materials.
Eastman et al. (2001) tested the effectiveness of vermicomposting
for pathogen destruction in biosolids (sewage sludge from waste
treatment plant). The researchers "heavily" inoculated two
biosolids windrows with four different pathogens - fecal
coliforms, Salmonella, enteric viruses and helminth ova. Red
worms (Eisenia fetida) were then added to one of the rows at a
ratio 1:1.5 (worm wt:biosolids wt) and left to process the
materials. After 144 hours the row with the worms was found to
contain significantly fewer pathogens than the control row. The
results strongly suggest that vermicomposting could be used to
achieve EPA Class A standards for biosolids.
In a 2006 BioCycle article, Craig and Ankers report on a
promising 'real world' example of a large-scale vermicomposting
system being used successfully to achieve Class A biosolids. A
Pennsylvania wastewater plant has become the first in the U.S. to
be granted a permit to make use of biosolids that have been
processed by worms. The plant utilizes a large-scale
(semi-continuous) flow-through reactor designed by Vermitech
systems (of Australia) to process biosolids 'filter cakes' - a
material that was previously landfilled. According to the
article, the resultant vermi-processed material has been well
received by local vineyards, golf courses and sod producers.
There is some evidence to indicate that worms can reduce
pathogens in manures as well (although this doesn't appear to
have been studied as extensively). Murry and Hinckley (1992)
studied the fate of Salmonella in horse manure processed by
Eisenia fetida. They observed an 8% reduction in the presence of
worms, and only a 2% reduction in treatments without worms. The
horse manure was completely sterilized prior to use in the
experiment, and the ratio of worms to waste was lower than in the
Eastman study - potentially explaining why reductions were not as
dramatic in this study.
Despite the evidence suggesting potential pathogen destruction
during the vermicomposting process it is still best to use
caution when dealing with materials such as manures and sewage.
Part of the problem is that even if the passage through the
earthworms' gut IS destroying these organisms, how can we be sure
that all the material has in fact passed through a worm? Even in
the most efficient systems there will undoubtedly still be at
least some unprocessed materials.
As an extra precautionary measure when using manures/sewage as
worm food, I'd recommend hot composting the materials for at
least a few days prior to feeding it to your worms. This has the
added bonus of speeding up the process and destroying weed seeds
Craig, L. and S. Ankers. 2006. Vermiculture produces EQ Class A
biosolids at wastewater plant. BioCycle 47(2): 42.
Eastman, B.R., Kane, P.N., Edwards, C.A., Trutek, L., Gunadi, B.,
Sterner, A.L. and J.R. Mobley. 2001. The effectiveness of
vermiculture in human pathogen reduction for USEPA biosolids
stabilization. Compost Science & Utilization 9: 38-49.
Murray, A.C. Jr and L.S. Hinckley. 2006. Vermiculture Produces EQ
Class A Biosolids at Wastewater Plant. BioCycle 47(2): p.42.
Paul Barnes wrote:....
Basically my question is does anyone know what would be the minimum size of bin/barrel that we'd need to be able to successfully turn humanure into compost? Note, we're in the UK (Scotland) so a fairly mild climate, and we wouldn't mind leaving the bins for a longer period to compost.