Available from Amazon.com for $14.99  (and from other retailers at a similar price) is this handy device that filters and decontaminates water whenever someone uses it as a straw. Lifestraw removes 99.9999% of waterborne bacteria and 99.9% of waterborne protozoa. Each Lifestraw filters the amount of water that the typical person drinks in the course of a year. Made (I think in Poland) by the Swiss company Vestergaard , Lifestraw – from its conception to the system that allows it to be produced and distributed and sold at a price that’s about 2/3rds of the amount of money that an ordinary American worker earns in a single hour – is a marvelous example of human ingenuity and of the largely unseen and under-appreciated productive power of a globe-spanning market. This product is also yet another example of how the environment is cleaned by capitalism . And since Lifestraw became available, the process of reducing water pollution is a bit less of a public good  than it was before the availability of Lifestraw.
I thank Warren Smith for sending me this article about Lifestraw .