Enhanced disinfection of wastewater by combining wetland treatment with bioelectrochemical H2O2 production

A highly-loaded constructed wetland (up to 44 ± 21 g COD m−2 d−1) was connected to a bioelectrochemical system (BES) to produce hydrogen peroxide for disinfection purposes. The anode delivered a current from the wetland effluent up to 3.5 A m−2 (maximum 62% anodic efficiency) but was limited in the supply of organic carbon. Hydrogen peroxide could be produced in situ in wetland effluent. Production rates were tested at various current densities with a maximum rate of 2.7 g melectrode−2 h−1 (4 h at 10 A m−2, 41% cathodic efficiency). Little difference was observed between production rate in wetland effluent or a 0.3% NaCl solution. The resulting hydrogen peroxide (0.1%) was used to disinfect wetland effluent successfully (<75 CFU ml−1 after 1 h contact time). The combination of wetland water treatment with peroxide production in a BES thus enables generating higher water qualities, including disinfected water, without external input of chemicals.