<p>Wastewater treatment plays a vital role in the tannery industry due to the large number and variety of pollutants produced, as well as the significant amount of water required for industrial activities. Consequently, there is a growing interest and concern in advancing more efficient wastewater treatment technologies. Emerging electrochemical methods, particularly electrocoagulation (EC), electrooxidation (EO), and a hybrid of both, have recently garnered attention as potential wastewater treatment solutions due to their broad applicability and environmental compatibility. In this study, synthetic tannery wastewater (STWW) was treated by combining EC-EO using mixed metal oxide electrode (TiRuO₂/IrO₂). After conducting preliminary testing and determining the suitable range of variables affecting both processes, experiments were structured using Box<b>–</b>Behnken design (BBD). The main aim was to lower Chemical Oxygen Demand (COD) and identifying the variables affecting the efficiency of both processes. The study examined the effects of different factors, such as pH, current, and time. EC process achieved a COD removal efficiency of 69.78% under optimal conditions—current of 0.80A, pH 6.9, and a treatment time of 65&#xa0;min. However, this level of treatment was insufficient for effluent treatment. To address this, further treatment is required. To determine the optimum operating conditions, multiple responses optimization based on Central composite design (CCD) with desirability function was used in hybrid process (EC-EO). In contrast, the hybrid process demonstrated a higher COD removal efficiency of 79.04% under its optimal conditions: a current of 0.702A and a treatment time of 110&#xa0;min.</p>