Development and testing of bioelectrochemical reactors converting wastewater organics into hydrogen peroxide.

In a bioelectrochemical system, the energy content in dissolved organic matter can be used to power the production of hydrogen peroxide (H(2)O(2)), which is a potentially useful chemical at wastewater treatment plants. H(2)O(2) can be produced by the cathodic reduction of oxygen. We investigated four types of gas-diffusion electrodes (GDEs) for this purpose. A GDE made of carbon nanoparticles bound with 30% polytetrafluoroethylene (PTFE) (wt./wt.C) to a carbon fiber paper performed best and catalyzed H(2)O(2) production from oxygen in air with a coulombic efficiency of 95.1%. We coupled the GDE to biological anodes in two bioelectrochemical reactors. When the anodes were fed with synthetic wastewater containing acetate they generated a current of up to ∼0.4 mA/mL total anode compartment volume. H(2)O(2) concentrations of ∼0.2 and ∼0.5% could be produced in 5 mL catholyte in 9 and 21 h, respectively. When the anodes were fed with real wastewater, the generated current was ∼0.1 mA/mL and only 84 mg/L of H(2)O(2) was produced.