SINGAPORE - It weighs no more than 300g, fits easily into a backpack and looks like any other plastic bag.

The bag, called Fieldtrate Lite, filters dirty water, such as river water, through a membrane and turns it into potable water in the same time it would take to run it from the tap.

It is the brainchild of Singapore start-up WateROAM, which designs portable water filtration systems for use in disaster relief operations or rural communities without access to clean water. The social enterprise, set up last August, is run by Mr David Pong, 26; Mr Lim Chong Tee, 24; Mr Vincent Loka, 22; and Mr Pooi Ching Kwek, 27. They were schoolmates at the National University of Singapore (NUS).