A Soil-Filled Floating Microbial Fuel Cell Doubles as a Self-Powered Sensor for Freshwater Pollution
Microbe-packed soil serves as the basis for this low-cost, environmentally-friendly way to monitor freshwater sources for organic pollution.
Researchers from Japan's Ritsumeikan University have developed a way top monitor rivers and other freshwater bodies for pollution, without contributing to the problem themselves — using a low-cost biosensor powered by a microbial fuel cell.
"We developed a self-powered, stand-alone, floating biosensor based on a microbial fuel cell (MFC) for early organic wastewater detection," Kozo Taguchi, a professor in the College of Science and Engineering's Department of Electrical and Electronic Engineering at Ritsumeikan University and leader of the study. "The MFC case was fabricated by a 3D printer and the electrodes were fabricated from low-cost carbon-based materials."
The microbial fuel cell is designed to generate a small electrical current from the activities of the bacteria inside the cell. The trick to the team's work is that the amount of energy you get out of the fuel cell is proportion to the amount of waste available for the bacteria to consume — meaning the power source itself is the sensor.
The team's prototypes are based on low-cost carbon-based materials and are designed to float down a river or on the surface of a lake. As the bacteria-filled soil in the fuel cell becomes soaked, the organic pollutants — including untreated wastewater — feed the bacteria and drive the sensor. The energy is used to flash an LED, which serves as the sensor's readout: when the flashing begins, the contamination in the water exceeds a set threshold level; the faster the flashing, the more contaminants are in the water.
"Because the FMFC [Floating Microbial Fuel Cell] biosensor produces its own electricity, it requires no external power supply," Taguchi adds of the benefits to the team's approach. "Moreover, it can be used in early detection systems that monitor influxes of organic wastewater in freshwater bodies."
The idea of a technology which can turn something negative, like freshwater pollution, into a positive is at the heart of our upcoming Hackster.io Impact Summit, taking place November 14th-15th, 2023 and covering topics including the sustainable development of societies, the modernization of critical infrastructure, and the use of artificial intelligence (AI) to power sustainable cities. The event is virtual and open to all, with registration available now on the official site.
The team's work has been published in the Biochemical Engineering Journal under closed-access terms.