Compost Teas: 24 hour, EM, IM, BD & fermented plant extracts

[Steve Diver <steved AT ncat.org>]

Here's an online paper (August 2004) from Chennai, India,
on vermicompost treatment of sewage sludge and pathogen
reduction.....  located in the The Green Pages - The Global
Directory for Environmental Technology.

They make special note of worm-cultured microbial destruction
of pathogenic organisms.

Regards,

Steve Diver
http://www.attra.ncat.org

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Municipal Solid Waste Management through Anaecic Earthworm,
Lampito Mauritti and their Role in Microbial Modification

By Ganesh Kumar Arumugam, Sekaran Ganesan, Ramani
Kandasamy, Ravindran Balasubramani and Prasad Rao Burusa

Department of Environmental Technology - Central Leather
Research Institute, Adyar, in Chennai - India.

August 2004

http://www.eco-web.com/cgi-local/sfc?a=/editorial/index.html&b=/editorial/040831.html

Abstract

A laboratory experiment was carried out for proper management
of sewage sludge generated from municipal wastewater treatment
plant. The experiment dealt with the stabilization, through the
action of anaecic earthworm, Lampito mauritii, of mixtures
containing Sewage sludge, Rice straw and Cow dung.
The vermicomposting of mixtures were carried out for 70 days.
The vermicomposting resulted in significant reduction of total
organic carbon and increase in total kjeldhal nitrogen. The
heterotrophic bacterial population increased throughout the
experiment and enteric bacterial populations like Salmonella,
Shigella and Escherichia species reduced dramatically and
declined to nil on vermicomposting.

There was no reoccurrence of these pathogens on further period.
The mid gut analysis of the worm also proved the changes in
microbial population during vermicomposting.


Discussion excerpts:

Although the earthworms enhance soil microbial activity
by improving the environment favourable for microbes (Syers
et al., 1979) the fate of microorganisms during the gut transit
through earthworms is still controversial (Wolter and Scheu 1999).
The gut analysis and casting analysis proved the removal of
Salmonella, Shigella and faecal coliform, in 35 days. However,
the Pseudomonas, cellulolytic bacillus sp. and heterotrophic
bacterial population were increased at the end of vermicomposting
period, indicating the selective nature of earthworms in the removal
of microorganisms. This corroborates with the findings of the
researchers proving that earthworms include microorganisms in
their substrates as a food source and can digest them selectively
(Edwards, 1988; Edwards and Bohlen, 1996); (Bohlen and
Edwards, 1995).


The microbial population dynamics of whole vermicomposting
process is very complex, so isolation of all bacterial species
in the vermicompost was not completely accomplished. The
most media used in the present investigation are selective
medium and they do not support the growth of many organisms
present in vermicompost.



Conclusion excerpts:

These results presented in this paper indicate the way by which
the biosolids can be composted along with rice straw and cattle
dung. The decomposition process was enhanced by the presence
of earthworm and aerobic heterotrophic population. Moreover the
paper also precisely pinpoints the way by which the earthworm
selectively inhibits the growth of bacterial pathogens present in
domestic sewage sludge.


Survival of pathogenic organism Salmonella, Shigella and Faecal
coliform were observed to reduce to nil concentration after
vermicomposting, proves this pathogens are eliminated as they
enter in food chain of the earthworm. However, Pseudomonas
and Bacillus sp. were considered to be microflora responsible
for the reduction of pathogens and metabolisation of other organics
in sludge and they were not vanished during vermicomposting.


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