In what may turn out to be a boon for developing countries, scientists claim to have created a device which can generate electricity from waste water.
A team at Pennsylvania State University in the US says the technology would simultaneously treat the water and the process could be used to provide clean water and power for homes in developing nations, the 'Science' journal reported.
Researchers in the Netherlands have for some years been exploring the idea of generating renewable power along the country's coastline, where fresh water from rivers meets the salt water of the sea, using reverse electrodialysis.
In this process, fresh water and seawater are placed in intermittent chambers separated by membranes, and an electrochemical charge is created.
The Penn State team says RED technology is problematic because of the large number of membranes required, and because power plants have to be located by the sea.
These use organic matter in solution to create an electric current -- in this instance waste water.
The prototype technology also bypasses the need for salt water by using ammonium bicarbonate solution as a substitute, meaning the system could work in communities far from the sea.
The ammonium bicarbonate solution will be constantly recycled, using waste heat from local industry.
"If we treat waste water in just a microbial fuel cell, we don't create much power and it takes a long time. In our process, we have the MFC part which is treating waste water and creating energy, and we have the RED stack which is just boosting that process, it's making it happen efficiently," team leader Prof Bruce Logan told the 'BBC'.
He says the process could potentially be used anywhere, but could provide both clean water and power to communities in developing countries.
"The main application right now is in waste water treatment where you could effectively treat the water, but also gain some extra energy from waste heat. Instead of having a net drain, we have a net gain," he said.
