Evaluation of a new electrochemical concept for vacuum toilet wastewater treatment – Comparison with ozonation and peroxone processes

New electrochemical advanced oxidation processes (EAOPs) are becoming increasingly attractive for use in wastewater treatment. A reactor with a boron-doped diamond anode and a gas diffusion cathode seems to be a promising approach for water purification, because of the in situ generation of highly reactive species such as anodic •OH radicals and cathodic H2O2. To evaluate the application potential of this EAOP concept, the treatment efficiency and energy efficiency were compared with those of well-established AOPs such as ozonation and peroxone processes (O3 + H2O2). In this study, the innovative electrochemical batch treatment of artificial toilet wastewater showed a COD degradation efficiency of 38.1%, which is higher than that obtained using ozonation (17.0%) or the peroxone process (25.7%). Additionally, the specific energy demand is lower for EAOP (93.6 kWh/kg mCOD) than for ozonation (125.4 kWh/kg mCOD) or the peroxone process (134.5 kWh/kg mCOD). •Simultaneous generation of two strong oxidants•No H2 generation at the cathode → no oxyhydrogen reaction → minimizes chance of explosions.•In comparable experiments, the best COD degradation was achieved with electrochemical reactor.•Lowest specific energy demand achieved with electrochemical reactor.•Electrochemical reactor has low space requirements (good for use in trains).