London, August 25 (ANI): Researchers have developed a new microbial desalination system that can remove 90 per cent of the salt from a seawater-like solution.
Microbial desalination could offer big advantages over the methods currently used to purify seawater, which require enormous pressure to operate, and gobble up huge amounts of energy.
According to a report in New Scientist, Bruce Logan, an electrical engineer at Pennsylvania State University in University Park, and colleagues at Tsinghua University in Beijing, China, adapted one of these techniques, electrodialysis, in which electricity draws ions from salt water through semipermeable membranes into two chambers.
The negatively charged chlorine ions are drawn in one chamber and positively charged sodium ions into another - leaving the water salt-free.
Logan's team replaced an external source of electricity with a microbial fuel cell, which transforms bacteria into batteries.
When the bacteria metabolise nutrients - acetate in this case - they generate protons and electrons.
The researchers then used these positive and negative charges to drive desalination by electrodialysis.
The device removed between 88 and 94 per cent of the salt from various salt-water solutions, including one that approximated sea water.
This water might still leave you thirsty, but Logan thinks that efficiency can be improved.
Furthermore, even with its performance so far, microbial desalination could produce drinking water from brackish waters that contain much less salt than seawater.
"We just wanted to show that it was possible," said Logan. "We hope that there will be more research going into this and it could lead to a commercial technology," he added.
"You could also consider this to be a pre-treatment technology for seawater," he said.
Using microbial fuel cells to draw most of the salt out of seawater first could make conventional desalination techniques, such as reverse osmosis, more economical.
The team is now working on microbial fuel cells that subsist on waste water.
According to Lars Angenent, a microbial fuel cell researcher at Cornell University in Ithaca, New York, advances in electrode and membrane materials will be key to commercializing microbial desalination and other microbial fuel cell technologies. (ANI)