As I have written in the previous post, nanotech may be able to revolutionize drinking water provision. Recently at the 2009 TED, an engineer demonstrated a non chemical nano-filtration bottle that could change filthy water into drinking water in a matter of second. The cost of the bottle is still quite high, around 116-170 GBP depending on the volume (filtration of up to 4,000 to 6,000 litres).
However, with better manufacturing, the price of the filter may significantly decrease in the future. If employed in a larger scale, this technology may decentralize water treatment facility and open doors for competition in the water sector.