Michael Wilson, a professor in the UK, watched the way that a sultana expands as it absorbs water through tiny pores in its skin. Inspired by this, he decided to invent a method of purifying water by osmosis using a cellulose membrane. He soon realised that by combining the technologies of cellulose, osmotics and dehydrated foods, he could design a product that would save millions of lives in disaster areas.
A company called UCB based in Switzerland set about developing the product. It put together a team of specialists in cellulose membranes and coating and production engineering, along with advisers from nutrition networks, humanitarian organisations, supplier and distribution groups, and government aid organisations. They decided that the best solution would be to develop a sachet that, when put in contaminated water, absorbed only clean water and left all impurities outside.
A prototype sachet was sent to the International Centre for Diarrhoeal Disease in Bangladesh, one of the best-regarded hospitals for waterborne diseases in the world. They tested the product and recommended it for field trials.