/sci/ - Science & Math

20 years.

http://cen.acs.org/articles/90/web/2012/02/Battery-Desalinates-Seawater.html

>For the first time, researchers have designed an electrochemical cell that can desalinate seawater. They think that its cost and efficiency eventually could improve on standard techniques of purifying seawater.

The existing method is reverse osmosis. The downsides are power use; A sufficient model can be had for between $1,000 and $5,000 depending on the output you need and they can run from a 12 volt source. Even so, this new method promises to be cheaper, solid state, without any filters that need replacing/cleaning, with comparable space usage.

http://www.gizmag.com/edible-nontoxic-carbon-filter/19955/

>Not only can the filters be emptied of CO2 and reused, but they also have a way of letting people know when they can't hold any more. Each crystal has an indicator molecule placed inside of it, which changes color according to the surrounding pH. When the whole sponge changes from yellow to red, that means that it has reached capacity. After being emptied, its color returns to yellow.

One of the biggest expenses of ongoing habitat operations is sodasorb. It's a nontoxic chemical CO2 absorbant that isn't reusable, so when it fills up completely with CO2, it has to be disposed of and replaced. The advent of reusable CO2 absorbant is a big deal, as it eliminates one of the main overhead expenses of operating an underwater living structure.