It costs WAY WAY too much. He "hopes" to get it below $2000, which means right now it's more than that. And after you read the $/L estimate, add in the cost of fuel and you'll see the device is not cost effective (when compared to other devices that do the same thing).
It would come down in cost with economies of scale, and improved production techniques, and... in 20 years, it would be out of patent.
I think there is a moral dilemma when someone creates something immensely valuable, but wants to be paid for it. But... wouldn't a world in which people didn't get paid quickly become rotten? And is it any different from people needing money for life-saving surgery (because the surgeons, hospitals and suppliers all want to be paid). See also the pied piper.
Factual content: there's a camping device for purifying water with ultraviolet light http://www.steripen.com/ but it just kills things, and won't remove salt or arsenic.
See, that looks cheap to me. DK claims 1000 liters/day for a cost of 0.2 cents/liter; let's be pessimistic and assume 500. (Maintenance would be my biggest worry, but let's keep it simple.)
Now if we take grinding poverty as a per capita income of $1/day and consider a village of 100 people, that means everyone in the village could have 5 liters of pure water a day at a cost of 1 day per week - a 14% 'tax' for 1 year.
That's a big economic hit for a very poor village, but it would not surprise me to find that such a village might lose more than 14% of its productivity to a combination of acquiring cleanish water and lost productivity due to water-borne diseases.
$5200 is not big bucks to us in the developed world. Surely it would not cost too much to buy 5 of them and do a year long comparison of 10 villages where half of them have the system and the other half serve as a control. Even if you add in setup costs the total bill for such an experiment would only be $75k.
I think there is a moral dilemma when someone creates something immensely valuable, but wants to be paid for it. But... wouldn't a world in which people didn't get paid quickly become rotten? And is it any different from people needing money for life-saving surgery (because the surgeons, hospitals and suppliers all want to be paid). See also the pied piper.
Factual content: there's a camping device for purifying water with ultraviolet light http://www.steripen.com/ but it just kills things, and won't remove salt or arsenic.