Scale-up modelling and life cycle assessment of electrochemical oxidation in wastewater treatment

Abstract

The need to improve current wastewater treatments to ensure a clean and sustainable water supply is an unquestionable contemporary challenge. It is therefore essential to facilitate knowledge transfer between research institutions and the industry by developing novel technologies to a proof-of-concept stage, demonstrating both treatment efficiency and compliance with environmental criteria. This study has combined process modelling for the design of an electrochemical Advanced Oxidation Process (eAOP) to remove carbamazepine (CBZ) from wastewater with the identification of the environmental impacts associated with its operation. A comprehensive set of scenarios considering several reactor designs and operating conditions provides the assessment framework to identify the influence of different process variables on the environmental profile of the pilot-scale eAOP. The most sustainable treatment corresponds to the operation of a standardised modular reactor in batch mode, especially when the wastewater has a low concentration of scavengers, such as other ions, organics or pollutants. Nevertheless, in all scenarios evaluated, the main environmental hotspot was attributed to the electrical energy consumed by the auxiliary pumps rather than the electrochemical reactor itself. In comparison to other AOPs, our system showed considerably lower impacts in the global warming potential (GWP) category, with a minimum of 7.6 kg CO2eq. per g CBZ removed for the most promising scenario. This demonstrates the implementation potential of eAOPs as well as the importance of data from scaled-up experiments, where optimisation should focus on mitigating the impacts of energy-intensive pieces of equipment.