Engineers from Murdoch University in Australia hope to build a prototype “bubble greenhouse” that could be used in arid areas as a low-tech way to turn saltwater into fresh water and grow food, says SciDevNet, a website devoted to international development. The engineers estimate that a 150-square-meter greenhouse could produce eight cubic meters of water and up to 30 kilograms of crops daily. “The sealed structure would protect crops from insects and disease, while the technology should be relatively simple to implement and use in isolated areas.”
For desalination, the project would use two water-filled “bubble” columns with a stream of thousands of tiny bubbles moving through heated water to release salt-free water vapor, which would be condensed and used to water plants. A U.S. engineer not associated with the project says bubble columns are less expensive than conventional methods for creating salt-free water vapor, but still too expensive for staple crops.