Of course this is via Micah, via Green Diary. Check out this robot plant from Plantas Nomadas that  can walk about the contaminated rivers to nourish its microbial fuel cells. As it sips from the polluted water source, the elements of the contaminated water serve as nutrients for its microbes and they disintegrate to create energy during the process.

You can see Plantas Nomadas, designed by Mexican artist Gilberto Esparza, at Laboral, Gijón, Spain through June, 7, 2010.