• Optimum COD removal of 59.51 % at 12.60 V, 1 h electrolysis, and 26.60 g/L electrolyte. • Operating cost was 3.66 USD/g-COD with a cumulative uncertainty recorded at 1.20 %. • EC was employed for COD satisfaction level of 74.42% at the compromise solution. • Total operating costs decreased by 63.9%, from 10.14 USD/g-COD to 3.66 USD/g-COD. Palm oil mill effluent (POME) is an organic-rich wastewater produced during palm oil production, characterized by high levels of suspended solids, oil, grease, and biodegradable compounds. Conventional POME treatment technologies such as ponding systems, microbial fuel cells, and supercritical water gasification are commonly associated with long retention times, substantial energy demands, and process complexity, respectively. Electrocoagulation (EC) has emerged as a sustainable alternative by combining electrochemical and physical processes without chemical additives. Previous studies have optimized EC focusing on efficiency without addressing costs. This gap reduces the relevance of existing results for potential scale-up applications. The present study applied fuzzy multi-objective optimization to identify EC conditions that maximize chemical oxygen demand (COD) removal while minimizing cost. Operating conditions varied for voltage (10 V to 20 V), electrolysis (1 h to 3 h), and electrolyte concentration (13.30 g/L to 26.60 g/L). The ε-constraint method was utilized to generate Pareto front from response surface methodology (RSM) equations. The fuzzy optimal result achieved 59.51 % efficiency at 3.66 USD/g-COD removed, and a total cost reduction of 63.9 % under optimum conditions of 12.60 V, 1 h electrolysis, and 26.60 g/L electrolyte. The satisfaction levels for COD and cost were 0.7442, with cumulative uncertainty of 1.39 %. These findings demonstrate the value of integrating economic and technical performance in EC optimization, enhancing its viability for POME treatment. Future research should focus on scaling EC systems to pilot and full-scale applications and integrate EC with other advanced treatment technologies to further improve cost-effectiveness and efficiency.
Cabrera et al. (Tue,) studied this question.