Lots of filter plants use renewable energy sources, any filter plant that has its source above it's filter bed and its customers are below its grade, is using gravity, (also known as hydropower).
That system has been around for centuries. Even the Romans used that trick.
I appreciate your response, but i was more interested I was interested in the potential of using solar pv cells, wind turbines, geothermal, biomass, hydrogen, or fuel cells at water treatment/purification facilities.
illhp
When looking at the choices of energy that you describe, I am hesitant that those sources are very available at prefered treatment plant locations. example
If it is sunny there is not much water
If it is windy the water will have blown debris prevelent
If it is next to a geothermal site, how do you keep the hot water/steam away from the water to be treated. Geothermal sources tend to have high amount of impurities.
If it is near biomass source, who wants a treatment plant next to waste facility.
If there is hydrogen source close, it must be near a petroleum facility.
All of these cases will cause the designer to look elsewhere for the source of water. It is a whole lot easier to treat clean water than dirty water.
but the one source that may be there is hydropower, and designers will go to great lenghts to use this power to drive their systems.
I just joined this site when i saw your thread. water treatment is not my field but I do know that there are people using solar power to treat water. I am not sure whether it is on a commercial basis but I hope this helps. The technology that is being used is called CSP. It is an abbr. for Concentrated Solar Power.