<p>Electronic waste has emerged as a critical global concern due to its complex mix of metals and plastics, which poses significant challenges for conventional solid waste management systems. Within this category, waste fan capacitors represent a notable proportion of the discarded waste, yet offer limited potential for by-product recovery through traditional recycling processes. Owing to their metallic and conductive properties, however, they hold promise for reuse in energy-related applications, particularly in Microbial fuel cells (MFCs), where electrode materials play a crucial role in determining performance, power output, and overall system cost. Consequently, the development of electrodes that are cost-effective, stable, and durable becomes vital for enabling their practical and widespread adoption. In this study, the reuse of waste fan capacitors as anode materials was evaluated for application in microbial fuel cells and was compared against commercial carbon electrodes. Two MFCs were operated using real sewage wastewater with an initial chemical oxygen demand (COD) of 2,700 mg L^− 1. The microbial fuel cell equipped with the reused waste fan capacitor demonstrated superior performance, achieving a maximum voltage of 871 mV, a peak power density of 278.9 mWm^− 2, a COD removal efficiency of 87.3%, a decolorization efficiency of 81.6%, and a total dissolved solids (TDS) removal efficiency of 86%. These results indicated the potential of electronic waste-derived materials as sustainable and effective alternatives to conventional electrodes in bioelectrochemical systems.</p> Graphical abstract <p></p>