Re-use waste energy. A third of our food is wasted each day so they can be put to use as compost piles. You would be surprised to find out how much energy is provided by a compost pile. Heating water would be much more efficient economically and also better for the environment.
A friend and I are trying to create a project where compost energy can be used for desalination. We are looking for other's insight into this. Please feel free to comment!
http://www.scienceforums.net/topic/85119-desalination-powered-by-compost-energy/
