It's not that I think their AWG isn't good enough, it's that I think a AWG isn't the answer to the problem they're addressing.
If the goal is to provide clean drinking water in emergency situations, then this could definitely help. If the goal is to provide a sustainable source of clean water for a large population, then this is not the solution (there's a pun in there somewhere).
The only downside is that the water table needs to be relatively shallow