In rural and suburban contexts handling manure and converting it to fertilizer is a solved problem: Eisenia foetida (& co.) https://en.wikipedia.org/wiki/Vermi

In rural and suburban contexts handling manure and converting it to fertilizer is a solved problem: Eisenia foetida (& co.) https://en.wikipedia.org/wiki/Vermicomposting https://en.wikipedia.org/wiki/Vermicomposting and Vermicomposting Flush Toilets: > A simple, proven, low tech and open source approach for ecofriendly human waste disposal http://www.vermicompostingtoilets.net/ http://www.vermicompostingtoilets.net/