Sludge Watch ==> UK - Human Waste & Organic Farming - Toxic Combination

[Maureen Reilly]

http://green.onevillage.tv/?p=153

Tue 12 Jun 2007

Human Waste & Organic Farming - a Toxic Combination?
Posted by jefbuder under IF&WMS Animals , IF&WMS Food Production , Areas of 
Concern

In an email to George Chan someone in the UK reports that an alarming new 
threat to organic farming has arisen. He says that the Thames Water Company 
wants to get rid of sewage sludge by having it approved for use on organic 
farms!

The Elm Farm Research Centre Bulletin (No. 82, February) said that the Soil 
Association Annual Conference in the UK allowed Thames Water it major 
sponsor to hold a workshop “to subtly present the case that sewage sludge 
should be allowed in organic farming.”

Delegates were split on the merits of using this material for nutrients and 
organic matter making a clear distinction between true ‘night soil’ — human 
waste mixed with straw etc. and modern sewage sludges which also contain 
detergents and other household and industrial chemicals.

The problem with this is that there are heavy metals present in the sewage 
sludge that have potentially adverse ecologically impacts. This would 
definitely affect the status of the farms that use it at least in terms of 
my understanding of USDA standards and definitely with regards to Third 
Party Organic Certification Standards.

This is hardly a problem limited to the UK. Waste managers are having 
problems persuading even conventional farmers to use sludge (In Germany its 
use is banned on conventional as well as organic farms and one wonders what 
they do with it).  So it is another of conventional groups trying to dump a 
fundamental problem with the design of modern waste systems onto to the laps 
of burgeoning but still tiny sustainability sector in particular organic 
farmers. However it is probably best to see this as huge opportunity to 
figure out how to process toxic laden organic waste flows so that they can 
eventually be introduced into organic farmer because obviously we can 
continue to contaminate the planet’s biomass resources. A stopgap strategy 
has to be development to cleanse these waste-flow until the whole human 
built environment can be completely redesigned.

The ultimate solution is a fundamental redesign of the built environment 
focusing on these three areas:
1.    Decentralized waste processing facilities that can process and also 
monitor waste closer to the source.
2.    Industrial facilities should process all their wastes in a closed 
system process similar to that put forward by ZERI.
3.    Municipal, commercial and residential facilities also need to be 
fundamentally redesigned so that persistent chemicals like chorline and 
others are not dumped into the waste stream.

Is human waste is a suitable material for biogas digestion? George says that 
it would be best to use confined farm animal rather than human waste because 
the amount of water we add by combining grey water with black water in 
conventional centralized systems dilutes the waste stream too much to really 
make it feasible to process it at least as compared to the potential 
benefits of processing confined farm waste.

However several cities in the USA have begun experimentation using the 
biogas from the anaerobic digestion process in their facilities to run fuel 
cell systems producing small amounts of electricity. Fuel Cell Energy has 
been a leader in this. Definitely it is preferable to extract the methane 
from the waste processing/decomposition process at municipal sewage 
treatment plants rather as it is the case that methane gas is 20 times more 
potent than CO2 as greenhouse gas and it is also is potential energy source.

In addition awareness of the potential of using human waste in slums in 
developing countries is growing.