Researchers from the Universitat Autònoma de Barcelona have reported that they have developed an efficient way to obtain electrical energy and hydrogen in a wastewater treatment process. The system uses bacteria which consume the organic material and generate electricity which is used to produce hydrogen.

Wastewater contains an elevated amount of chemical energy in the form of organic contaminants. To recover this energy, a special type of “exoelectrogenic” bacteria, which is capable of oxidising organic material and generating electricity, is used. With a small added voltage, much less than is used for water electrolysis, hydrogen can be recovered.

The results of tests have been very positive with high hydrogen production and energy intensity being obtained. Dairy wastewater yielded the best results in the tests. The researchers see these results as the basis for potential industrial development of this technology.