Lifesaving

Using this technology, the entire world can have access to clean drinking water for $20 billion every 3 years (less, presumably, as the technology improves over the years). For $8 billion every 3 years, half of everyone can have clean drinking water, which would at least meet the UN Millennium Development Goals. The UK alone already spends £12 billion in foreign aid every year. Does this sound like a good idea to anyone else?