Removal of contaminants of emerging concern and Escherichia coli from effluent using an optimized electrochemical reactor

Contaminants of emerging concern (CECs) in wastewater are a matter of great importance as they have a huge environmental impact. This work investigated the electrochemical oxidation (EO) technology as an alternative tertiary treatment in wastewater treatment plants (WWTP) aiming to simultaneous remove CECs and Escherichia coli. Platinum titanium (Pt/Ti) and metal mixed oxide (MMO, RuO2-IrO2/Ti) electrode materials with different shapes (bar, mesh and circular mesh) were tested. The results obtained showed that removal rate not only depends on CECs structure and physicochemical characteristics, but electrode material and shape play a key role in the whole treatment process. Overall, the removal efficiency increased (20-50%) for the recalcitrant CECs when using MMO with the electrode characterized by a higher surface area with a circular-mesh as both anode and cathode. Varying the current intensity had a relatively minor effect on the yield of CECs removal. CECs removals were greater than 90% with simultaneous removal of E. coli within 2 h. Overall, EO can be considered an ecofriendly process since no reagents were added and has a low estimated treatment cost of 1.1 euro/m3.