Electrocoagulation Applied to Domestic Wastewater Treatment: Statistical Optimization and Validation in Different Real Matrices

The increasing demand for sustainable water management has prompted the search for efficient domestic wastewater treatment technologies. Electrocoagulation (EC) has emerged as a promising alternative owing to its simplicity, efficiency, and potential for decentralized applications. This study investigated EC for treating domestic wastewater, focusing on optimizing operational parameters via the design of experiments (DoE). Initially, raw wastewater was characterized, followed by a fractional factorial design to screen for significant variables: operating time, current density, initial pH, and NaCl dosage. Results revealed that current density and pH were the most influential parameters on Chemical Oxygen Demand (COD) removal. Subsequently, a Central Composite Rotational Design (CCRD) optimized these key parameters. Optimal conditions were a current density of 85 A/m² and pH of 5.5, achieving COD removal efficiencies up to 78.2%. A cost analysis indicated the economic feasibility of EC for smaller effluent volumes, with an estimated operational cost of US$1.23 per cubic meter treated. Applying this methodology to real sewage matrices (Federal University of Sergipe WWTP and a residential condominium) showed variations in Biochemical Oxygen Demand (BOD), COD, and turbidity removal. These findings confirm EC's potential as a sustainable solution for domestic wastewater treatment in isolated communities.