In terms of being able to ...

In terms of being able to produce drinking water from any source - saline (ocean water) and contaminated or wastewater water - desalination by reverse osmosis is the most effective and cost efficent technology availalbe at present. It removes all pathogens and toxins from the source water and can process saline water from any water body on the planet. In terms of costs and energy - desalination is certianly costlier than water produciton from fresh sources (rivers, lakes, etc.) - water costs could be up to 5 times higher than these from a simple water well and energy could be up to 10 times higher. Nikolay