The NASA process starts with algae being placed in sewage-filled plastic bags called OMEGA which stands for ‘offshore membrane enclosures for growing algae’. The OMEGA bags are semi permeable membranes which NASA developed to recycle astronauts' wastewater on long space missions. When used with sewage, the membranes let freshwater exit but prevent saltwater from entering.
 

Jonathan Trent, lead researcher and scientist on the project at NASA's Ames Research Centre in California, said: “Firstly it is possible to produce sustainable quantities of biofuels that can replace the use of fossil fuels without competing for resources and land needed for food production. Secondly these valued products are produced, while at the same time they help cleanse municipal wastewater and remediate dead zones such as those in the Baltic Sea and thirdly it is possible to produce products, clean the oceans, and at the same time remove the greenhouse gas, carbon dioxide, from the atmosphere.”