We all know you can treat human waste to make purified water, and the Gates Foundation has a machine that could make contaminated water safe to drink in less than 5 minutes. It is called the Janicki Omniprocessor, and it can convert sewer goo into water, electricity, and some form of fertilizer. It is estimated that at least 2.5 billion people on earth do not have access to clean drinking water, so the humanitarian implications this machine is expected to be huge.
The Gates foundation has made a video demonstrating all the steps showing how the machine works. The demo ends showing Bill Gates himself taking a drink from the machine, knowing that just five minutes earlier that water was sewage.
Source: Gates Foundation (YouTube)