BioDigestX: A Nano-enhanced and IoT-integrated Biosink System for Domestic Kitchen Waste-to-biogas Conversion

The increased volume of domestic kitchen waste and the growing demand for clean cooking energy require efficient decentralised waste-to-energy solutions. Anaerobic digestion is a viable way to convert organic waste to biogas, but there is a tendency to view conventional domestic digesters as low-efficiency, unstable, and producing low-quality gas. In this paper, the proposed system is BioDigestX, a nano-enhanced, biosink-based, and IoT-integrated anaerobic digestion system to convert household kitchen waste into biogas. The system combines waste segregation on the source level with the help of a biosink, anaerobic digestion with the use of iron oxide (Fe3O4) nanoparticles, and real-time monitoring of system parameters, temperature, pH, gas pressure, flow rate, and methane concentration using IoT. To test the performance of the systems, two domestic-scale reactors were operated under mesophilic conditions, with one serving as a standard control and the other as a nano-enhanced reactor. It was found that the nano-enhanced reactor became stable within 7-9 days, compared to 12-14 days for the control reactor. Biogas production was raised by 22-28% to reach 0.42-0.48 m3/day, with an average daily increase of 0.32-0.38 m3/day to 0.42-0.48 m3/day. The methane concentration increased to 62-68% in the nano-enhanced reactor, compared with 52-56% in the control system, and the carbon dioxide level decreased to 28-34%. The concentration of H2S was minimized to 40-50%, dropped to 90-140 ppm. The increased quality of biogas favoured 1.5-2.0 hours of domestic cooking. The findings indicate that the combined application of environmental nanotechnology and IoT can significantly improve the performance of domestic anaerobic digestion. BioDigestX system is a sustainable, scalable, and reliable system used in managing decentralized waste in kitchens and the generation of clean energy that can be used to support the ideas of the circular economy and the low-carbon household energy program.