Electricity production by integration of acidogenic fermentation of fruit juice wastewater and fuel cells

In this work, the potential application of bio-hydrogen in a fuel cell was studied. To do that an activated sludge was acclimatized to an acidogenic culture producing bio-hydrogen. Once reached the steady state, several batch experiments were carried out by feeding a synthetic fruit juice industry wastewater to the acidogenic culture. The bio-hydrogen yield obtained when this synthetic fruit juice industry wastewater was fed was 1403 mol H2/mol hexose and the hydrogen percent in gas phase was 57%. In an average size fruit juice industry, this bio-hydrogen yield corresponds to a bio-hydrogen production of about 6000 mol H2/d. In the subsequent stage, a synthetic bio-hydrogen stream with the same composition of the cleaned bio-hydrogen obtained in the acidogenic fermentation was fed as fuel in a Fuel Cell, obtaining very similar power and polarization curves than that obtained when feeding pure hydrogen, differences lower than 10%. These results showed that the hydrogen stream obtained by the acidogenic fermentation could be used to produce electricity in a high temperature PEMFC. ► The potential use of bio-hydrogen, generated from wastewater, in a fuel cell was studied. ► The main by-products in the liquid phase of the acidogenic fermentations were acetic, lactic and butyric acids. ► In the fuel cell, the bio-hydrogen yielded similar power densities and voltages to that of pure hydrogen. ► Bio-hydrogen can be used as fuel in PEM Fuel Cells without significant energy looses.