It occurs to me that it may be possible for these countries to do this:

Build a system in which water is removed from sewage via direct sunlight transmission and captured.

1) sewage flows as usual to it's final destination.
2) Insert a large lens at ground level that has it's focus on the sewage flow below.
3) As water evaporates it will rise as steam towards the lens.
4) Insert a transparent 'collection cone' near the lens.
5) Insert a transparent 'collection bowel' below the 'collection cone'.
6) The bowel is connected to a pipe at the bottom.
7) Collected water can be further treated at the other end if desired via simple filters.

As far as I know a system like this is not in practice anywhere, but I could be wrong. The most expensive component would be the lenses but if protectvie covers are provided they should last for a very long time. Note that the transparent covers would require constant cleaning and a direct, unobstructed line of sight to the sun. The "cone" and "bowel" should not need direct cleaning, as it is in constant bombardment by steam and is not in contact with walls. Steam should not obstruct power of light beam very much.

If anyone would like to develop this idea further just give me a shout.

-Tommy Charles
7-28-09