Reverse Osmosis (Dragon's Den)

[Lorcan]

A few weeks back there was a reverse osmosis water filter on Dragon's Den. Would reverse osmosis render sea water drinkable?

[Clanad]

It's the preferred method of desalination in many locations. It does require a lot energy and the filtration membranes are quite expensive, but for areas such as Saudi Arabia, where cost is not much of an objection, it works very well...

[kwicky]

I also saw that item on Dragons Den which received support from the 5 millionairres one of which brought up the replacement of the membrane every year. The water container looked similar to that used by caravanners when collecting water from a standpipe and rolling it back to the caravan but in this case from a dirty waterhole.

If these filtration membranes are very expensive as sugested by Clanad its difficult seeing this idea take off?