For most people, having a open stream of sewage running past your backyard is a problem, not an asset. That how Keshav Tavre, who lives in Bhiwandi, India, saw it, until he decided to set up a homemade filtration system. With a series of walls and layers of soil, he was able to filter the sewage until it was clean enough to use to grow crops. Later, he sold water commercially to local dye industries.
For a while, the local authorities were against his use of the resulting water for commercial gain, but since they weren't doing anything with the sewage, Tavre eventually won permission to make the best of what was once a bad situation. It’s a nice example of how you can polish a turd by taking reuse duties into your own hands (eew) when governments fall down on the job.