A saltwater greenhouse refugee camp on the Egypt/Israel border
Evapotrons are devices used at Burning Man to evaporate grey water quickly and efficiently (and they look pretty damn cool!). A tray is filled with grey water and a drum runs over it which is covered by a dark absorbent material. This drum is constantly driven round by the wind. The absorbed water evaporates from the dark material at a much faster rate than if it were just sitting in the trough.
The website explains this process more thoroughly as well as providing information about the history and development of evapotrons over the years.
The drinkpeedrinkpeedrinkpee project by Submersible Design details a novel way to extract the Nitrogen from urine in order to create fertiliser for plants. The process also has the added bonus of not overfeeding the marine environment which is a direct result of flushing urine directly into the sewers.