Start-up and performance of an activated sludge bioanode in microbial electrolysis cells

Microbial electrolysis cells (MECs) are a promising technology for wastewater treatment and simultaneous production of reduced value added compounds. The MEC performance strongly depends on the activity and efficiency of the anode and cathode (bio)catalysts. Here, the use of an activated sludge as inoculum of a MEC bioanode has been investigated. The bioanode was operated both in batch and continuous-flow regime and its performance evaluated in terms of substrate removal efficiency and current generation. The transient response of the bioanode to changes in the applied organic load rate (from 0 (g COD)/Ld to 1.08 (g COD)/Ld) was also assessed. Overall, the activated sludge turned out to be an excellent source of 'electro-active' bacteria and a good inoculum to start-up a MEC bioanode.