I recently saw a program that detailed a water treatment plant in Cork, Ireland (run by a company called Supercritical fluids which you may look up) that was using this amazing property of water to treat sludge water and generate energy.
Bear with me here. Essentially with sufficient pressures (about 30,000 PSI) and high enough temperatures (about 700 F) water enters a 4th state beyond gas/liquid/solid. That state, of course, is called supercritical. What it does is break down all organic compounds (human waste & pharmaceuticals) giving 99.99% pure water and 99.99% pure phosphorus (+ some CO2) in the output stream. This alone is very important. There is a huge clean water shortage coming in the near future and many places are struggling to remove the massive amount of pharmaceuticals from water now (giving rise to fish born with both sexual organs, for instance).
However, the really exciting thing is they are also powering 500,000 homes with 100% clean energy as well! All these compounds in supercritical water break their chemical bonds (which holds large potential energy). This nets a sizable exothermic reaction (meaning heat is released) in the form of super heated steam, which then functions as power plants normally do. Nuclear and coal plants generate steam to turn turbines which generates electric power.
Very exciting stuff!