In 2007 3 students proposed a water carrier that would purify water using mechanical energy from the process of wheeling it along. The reaction on Dragons Den was unprecedented and each of them offered to fund the project splitting it equally between the others. It looks like the implementation has been a great success, including designing the product to be locally manufactured and maintained. I’m sure not the most profitable strategy but certainly the one necessary for such a basic need.
It’s great to watch the original pitch:















