Efficient degradation of industrial slaughterhouse wastewater by electrooxidation process: impact of DSA anode materials on oxidation and operating costs

This research investigates the effect of the electrooxidation (EO) process on the treatment efficiency, discharge criteria, and water reuse or irrigation standards of industrial slaughterhouse wastewater (ISWW). The study was carried out on different anode materials such as (Ti/Pt-IrO₂, Ti/RuO₂-IrO₂, Ti/RuO₂, and Ti/IrO₂-Ta₂O₅), current densities (50-150 A/m²), and reaction time (0-540 min). COD, TOC, and turbidity removal efficiency under optimum conditions (anode = Ti/Pt-IrO₂, j = 150 A/m², and t = 360 min) were calculated as 99.6, 96.1, and 99.9%, respectively. The energy consumption and total operating cost were calculated as 68.3 kWh/m³ (15.4 and 50.6 kWh/kg COD or TOC) and 2.40 $/m³ (0.62 and 2.02 $/kg COD or TOC), respectively. Furthermore, the results are compared together with existing published/reported discharge criteria for adequate environmental release in different jurisdictions worldwide. Additionally, a relationship has been established between the World Bank Group/United States Environmental Protection Agency (WBG/US EPA) water reuse or irrigation standards. At the end of the study, the biodegradability of ISWW after EO was assessed using the carbon oxidation state (COS) and average oxidation state (AOS) parameters, and kinetic modeling with heterogeneous kinetics was comprehensively evaluated. The findings of the study show that the EO process using the Ti/Pt-IrO₂ anode is an efficient method for the ISWW treatment.