Use of Thiobacillus ferrooxidans in a coupled microbiological-electrochemical system for wastewater detoxification

We have developed a mixed system, etectrochemical-microbiological, that can be used for detoxifying organic compounds present in wastewater. In this s ystem, organic matter oxidation takes place at the anode of an electrochemi cal reactor while ferric iron reduction takes place at the cathode. We have used a growing culture of Thiobacillus ferrooxidans to regenerate the ferr ic ions consumed. The culture is used as the catholyte (solution in the cat hode compartment) of the system and is therefore permanently subjected to a n electric field. We have verified that, under our working conditions, the culture is able to oxidize ferrous ions for long periods of; time (up to 15 days) depending on the intensity of the applied current. We have checked t he performance of this system in methanol oxidation. Our results show that it decreases the energy cost by 35% when compared with the pure electrochem ical system traditionally used. (C) 1999 John Wiley & Sons, Inc.