One thing we have learnt this week – biochar from poop


Reaction vessel where faeces is converted to biochar research in the US.

Biochar was seen as one of the miracle cures for climate change nearly 10 years ago.  Like so many eco solutions greatly exaggerated claims were made about its ability to solve the climate crisis.  George Monbiot who hates all miracle cures (apart from nuclear power) makes a justified critique here.  Nevertheless even he conceded that it may have a niche role.  In Kenya one of the local water companies has found a way of turning poo into a fuel.  I call it biochar since it does contain other plant based products.  If you are eating turn way now.

The local water company collects poop from latrines and septic tanks.  Then it dries it in the sun.  Then it its it to 300°C and adds sawdust.  Finally molasses is added to the product as a binder.

There are 3 big problems this product helps to mitigate.  First, one major problem in the developing world is people cutting down trees to make fuel for cooking (not the only reason of course that trees are felled).  One of the big wins and easy ways of cutting emissions would be to stop deforestation.

Related to this is the use of paraffin or open fires to cook on.  Both create respiratory disease problems due to the release of particulates and paraffin obviously has a oil dependency. This product is being sold at a competitive price with these.

The last problem is that of health due to the spread of faecal bacteria.

One claim made about biochar is that its carbon negative (if you read the Monbiot article above you can see this could vary).  This product cannot be carbon negative since it involves heating to high temperatures and the addition of plant based products.  Nevertheless it seems to me press a number of the right buttons.  Another alternative that is going on all over the developing world is the use of poo to make biogas.



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