My only concern with something like this is that it's still ripe for legionella pneumophila contamination (i.e. the bacteria that causes Legionnaires Disease). While the collection method seems safe, the tank is still a stagnant body of water, and I didn't catch how they managed to keep the drinking water safe when I perused the article.
Don't get me wrong, it's fantastic that they've identified a way to harvest water without electricity (which is what I think the title should have been), but you'll still have to boil the water to kill off any sort of issues related to stagnant water.