Comparative Simulation of Advanced Oxidation Process and Electrocoagulation for Wastewater Treatment: A Two-Dimensional Diffusion–Reaction Study

Abstract

The growing challenge of wastewater pollution from industrial and domestic sources necessitates the adoption of advanced treatment technologies capable of removing recalcitrant pollutants. This study presents a comparative simulation of two promising processes—Advanced Oxidation Process (AOP) and  Electrocoagulation (EC)—in a batch reactor configuration. The AOP simulation models pollutant degradation using UV-induced photocatalytic reactions gov-erned by Langmuir–Hinshelwood kinetics, while the EC model captures electric field gener-ation, Faradaic coagulant production, and its interaction with pollutants. Both systems are implemented in a two-dimensional domain using finite difference methods, simulating pollu-tant and reactant transport via diffusion-reaction equations under no-mixing conditions. Spatial concentration profiles, COD removal trends, and energy usage are evaluated to understand sys-tem performance and limitations. Results show that AOP achieves 33% pollutant removal in 8 hours, primarily near the UV-illuminated surface, consuming approximately 0.4 kWh. In con-trast, EC achieves 23% removal, with degradation localized near the anode, consuming 0.102 kWh. Both processes are shown to be highly diffusion-limited in the absence of stirring, with steep concentration gradients restricting treatment to localized zones. These findings under-score the need for enhanced mass transport—either via mixing or flow—to achieve uniform performance. The study demonstrates the utility of simulation in evaluating spatial and ener-getic behavior of advanced treatment systems and provides a foundation for optimizing design parameters, operational strategies, and energy efficiency in future implementations. The mod-ular simulation framework can be extended to include convection, multi-species interactions, or real reactor geometries for broader application in wastewater engineering.