These are not your typical loos. One uses microwave energy to transform human waste into electricity, another captures urine and uses it for flushing and still another turns excrement into charcoal.
They are part of a Bill & Melinda Gates Foundation competition to reinvent the toilet for the 2.5 billion people around the world who do not have access to modern sanitation.
Scientists from around the world, including a team from London, have taken up the challenge, and the foundation announced some projects that will be getting more money to take their ideas from the lab to cities. There, local entrepreneurs will use the new technology to turn pollution into cash.