This is interesting. I’ve built a biochar stove and have used some of the charcoal/biochar in the tree bog at the farm where the stove spent the winter. The stove has a cooking attachment added now that provides a huge cooking surface and a hot and a warm oven. It was used for all the cooking for 20-30 people.
I need to get some good pictures with more detail and so you can see the whole thing together - heres the best I’ve seen so far (on flikr), which is a nice photo, artistically, but you cant really see much detail
The biochar was added to the treebog when we had a lot of visitors and the tree bog can start to smell a bit. It stops any odours.
Tree bogs are a nice simple way to get a toilet that is relatively safe(UK health and safety regulation compliant) as you leave the excreta in situ so there is no health risk in handling. Very easy to build but you need some wire mesh to stop children and animals getting into the poop chamber.
Its easy to make biochar using the pit method. Just need tools to dig a pit, a source of water, a few stones and some wood.
To make the char a good size for reacting with stuff/adding to soil a good/simple method is to put it in between sheets of cardboard and then drive over it with a vehicle.
Char can be very useful in water purification and pollution remediation also.