Sewage Sludge and The HEAP Trap
Folke Gunther, April 12, 2008

I was refraining from this, since I don’t think it is an item really belonging to the TP list, but now we are here.

1. Urine and faeces are excellent plant food. The reason we don’t use them directly is mostly cultural for the urine, I guess, but for faeces it is really an adaptive behaviour. Burning or charring cold be a good idea for faeces. The charring might make it sterile, and the non-gaseous nutrients, as phosphorus, would be returned to land, for a future production of new food. A large pat of the faeces is indigestible cellulose, why it could be a good thing to char it. The urine, which normally is sterile at the production site, could enrich charcoal very well.

2. Currently, the westernized wastewater behaviour is base on the MIFSLA (Mix First and Separate Later) philosophy This results in a mixture of high nutrient – high pathogen – high toxic – high water content mixture that is almost impossible to do something sensible with. Commonly, it is thrown away into the nearest lake or sea, where the harm it does is not immediately evident. On the other hand, avoiding the MIFSLA with a source-separating toilet is really easy, if you don’t live on the 21st floor and is forced to use the system, either you want it or not.

3. Living in dense communities (e.g. towns or cities) put another invisible restriction on you: As you use the MIFSLA system, you put the used nutrients on a smaller area than the food production area. It is like filling a glass of beer, when the glass is full, he leakage will equal the import. Normally, you stop the beer-filling process then, but you can not stop eating. It will end up in a steady state, which I call the HEAP trap.
I will add a ppt, trying to explain the HEAP effect and its cultural background.

YS
FG

Folke Günther
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