Wow, small world. I worked peripherally with the installation of one of these cookers during the construction of two schools.
The process is surprising simple. Oil recycled from cars and water is dripped on a steel plate super heated inside a furnace that creates the combustion process and fans the flames. Refuse is sorted so no combustibles go into the furnace, compostable materials are separated for composting, and other objects are laid out to dry before they are burned.
It requires a lot of cooperation but these things are earning awards and getting funded all over the continent.