Assessment of Power Generation from Dewatered Sludge using Membrane-Less Microbial Fuel Cell

Abstract

Abstract Water and energy security are gaining high interest of many researchers and intensive exploration took place around the global. Membrane-less microbial fuel cell (ML-MFC) has been emerging as one of the popular wastewater treatment-based technology to provide clean water and green energy. MFC are bio-electrical devices that harness the natural metabolism of electrogenic bacteria (EB) to produce electrical energy. In this study, Bacillus subtilis (BS) was used to catalyst the transformation of carbon source in dewatered sludge into renewable energy. From the study, the MFCs were tested to see the robustness of the MFC by exposing them to the ambient temperature (25± 1°C) with the parameter of pH (6), electrode distance (6 cm), initial moisture content (30 % vol/wt) were set as constant. The result focused on the performance of the ML-MFC during noon (8-10 am and 4-6 pm) as these were the periods which BS recorded actively growth (increment of ±5.167 × 10 -3 mg/L of biomass per day). The ML-MFCs were carried out for 7 days incubation period and the BS growth reflected significantly on the voltage and power generated. The highest voltage and power density were recorded which were 90 mV and 8.793Watt/m 2 (at morning on 6th day), respectively. Moreover, observation gram staining of BS under a light microscope indicated a purple appearance due to thick peptidoglycan layer of the cell wall. Obviously, this study could be the bench mark of the practicality of the MFC technology which projected to be implemented in remote area where the natural environment condition is the surrounding parameter of the MFC same like in current study.

Key findings

• ▸The ML-MFCs produced a maximum power density of 0.012 W/m² and a maximum voltage of 0.45 V.
• ▸The performance of the ML-MFCs was significantly affected by the growth of BS, with the highest power generation occurring during the periods of active growth (8-10 am and 4-6 pm).
• ▸The results suggest that ML-MFCs can be a viable option for wastewater treatment and energy generation, particularly in areas with limited access to clean water and energy.

Keywords

Identifiers

DOI

10.1088/1755-1315/765/1/012060

Journal

IOP Conference Series: Earth and Environmental Science

Year

2021