Electrode material impact on microbial fuel cell and electro-Fenton systems for enhanced slaughterhouse wastewater treatment: A comparative study of graphite and titanium

The treatment of slaughterhouse wastewater is a complex task demanding careful consideration due to its challenging nature. Therefore, exploring more sustainable treatment methods for this particular type of wastewater is of utmost significance. This research focused on the impact of electrode materials, specifically graphite and titanium, on the efficiency of microbial fuel cells (MFCs) and electro-Fenton systems in treating slaughterhouse wastewater. Both graphite and titanium electrodes displayed increasing current density trends, with titanium outperforming graphite. Titanium showed superior electron transfer and current generation (2.2 to 21.2 mA/m² ), while graphite ranged from 2.4 to 18.9 mA/m² . Titanium consistently exhibited higher power density, indicating better efficiency in converting current to power (0.059 to 22.68 mW/m² ), compared to graphite (0.059 to 12.25 mW/m² ) over the 48-h period. In removal efficiency within the MFC system alone, titanium exhibited superior performance over graphite in key parameters, including zinc (45.5% vs. 37.19%), total hardness (39.32% vs. 29.4%), and nitrates (66.87% vs. 55.8%). For the electro-Fenton system with a graphite electrode, the removal efficiency ranged from 34.1% to 87.5%, with an average efficiency of approximately 56.2%. This variability underscores fluctuations in the efficacy of the graphite electrode across diverse wastewater treatment scenarios. On the other hand, the electro-Fenton system employing a titanium electrode showed removal efficiency values ranging from 26.53% to 89.99%, with an average efficiency of about 68.4%. The titanium electrode exhibits both a comparatively higher and more consistent removal efficiency across the evaluated scenarios. On the other hand, the integrated system achieved more than 90% removal efficiency from most of the parameters. The study underscores the intricate nature of slaughterhouse wastewater treatment, emphasizing the need for sustainable approaches. PRACTITIONER POINTS: Microbial fuel cell (MFC) and electro-Fenton were investigated for slaughterhouse wastewater treatment. The MFC microbial activity started to decrease after 24 h. The integrated system achieved up to 99.8% removal efficiency (RE) for total coliform bacteria. Up to 99.4% of RE was also achieved for total suspended solids (TSS). The integrated system highly improved RE of the pollutants.