Carbon-Neutral Abattoirs: Modelling Novel Self-Subsisting Wastewater Microbial Fuel Cells for Bioenergy Generation and Organic Removal

Abstract

Environmental challenges such as climate change, emissions, indiscriminate waste disposal, and energy crisis are the focus of the Sustainable Development Goals (SDGs). There is a nexus between effluents and Bioelectrochemical Systems such as Microbial Fuel Cells (MFCs). In this study, twelve (12) locally fabricated Abattoir Wastewater Microbial Fuel Cells (AWMFCs) were developed, comprising (A, B, C, D – first stage) and (1, 2, 3, 4, 5, 6, 7, and 8 – second stage) from reusable HDPE/Plastic. The Microbial Fuel Cells (MFCs) were developed with different configurations and volumes, then fed with abattoir wastewater. The electrode used was a graphite rod, made from carbon, and was connected to a multimeter. The voltage across the circuit was monitored and recorded at an interval of twenty (20) minutes.

Reactor A and B produce a maximum density of 58.27 mWm^-2 (0.28 Wm^-3, 573.53 mAm^-2) and 64.75 mWm^-2 (0.31 Wm^-3, 604.57 mAm^-2) respectively. The 150 mL reactors (C and D) perform similarly to A and B. The maximum output of Reactor C was 27.42 mWm^-2 (0.22 Wm^-3, 0.04 mA cm^-2, 3.1 A cm^-3), which occurred at 200 minutes, compared to 37.50 mWm^-2 (0.3 Wm^-3, 0.04 mA cm^-2, 3.6 A cm^-3). Chemical Oxygen Demand (COD) removal was highest in Reactor D (32%), while efficiency ranged from 31% to 59%. Post Hoc Analysis of Variance shows a significant difference in power densities and current densities, while volumetric power shows no significant difference at an alpha value of 0.05. Moreover, COD removal in the second stage with eight (8) reactors in a two-cycle process was between 6.70% and 25.14%. The reactors reduced the organic matter of the wastewater and simultaneously generated bioenergy. Power and organic content were inversely proportional until a specific stage, after which this relationship changed.

Keywords: Bioenergy, Biofuel, Energy, Microbial Fuel Cells, Optimization, SDG, Sustainable, Voltage, Wastewater

DOI: 10.7176/CPER/67-01

Publication date: May 30^th 2026