Researchers at McGill University have improved the efficiency of a system that converts human urine into clean electricity while simultaneously treating wastewater.
The method uses microbial fuel cells (MFCs), which rely on bacteria to break down organic waste and release electrons, producing electricity. The McGill study provides new insight into how different urine concentrations affect the fuel cells’ performance, pollutant removal and microbial activity.
“While MFCs are known to clean wastewater and generate electricity, the specific effects of different urine concentrations on their electrochemical function, pollutant removal efficiency and microbial community behaviour are still not well understood,” said Vijaya Raghavan, a professor of bioresource engineering at McGill in Montreal, and co-author of the study. “This study addresses that gap by systematically examining how varying urine proportions affect the electrochemical and biological performance of MFCs,” he added.
Raghavan said the technology could help generate clean energy in rural sanitation systems, disaster relief camps and off-grid communities. Because the electrical signals produced by MFCs change in response to organic pollution levels, they may also serve as low-cost biosensors to monitor wastewater quality.
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The researchers constructed four dual-chamber MFCs and fed them mixtures of synthetic wastewater and human urine at concentrations of 20%, 50% and 75%. They monitored electricity production, pollutant removal and microbial behaviour over a two-week period.
“While synthetic wastewater provides a controlled environment for research, real-world applications often involve complex wastewater streams with varying characteristics,” the study states. “Human urine, a readily available and nutrient-rich waste stream, presents a potential substrate for MFCs due to its high organic content and presence of essential elements for microbial growth.”
The study found that higher urine concentrations — between 50% and 75% — produced stronger electrical output.
“Urine contains essential ions and organic compounds that support rapid microbial activity, which improves power generation and pollutant breakdown,” Raghavan said.
Analysis of the microbial communities showed that Sediminibacterium and Comamonas were the dominant bacterial groups in the fuel cells. Sediminibacterium was more prevalent at 50% urine concentration, while Comamonas became dominant at 75%.
Because such microorganisms help break down pollutants and transfer electrons within the fuel cells, changes in which species dominate may influence how efficiently electricity is generated, the researchers said. The findings suggest urine concentration plays a key role in shaping microbial communities and overall system performance.
Raghavan said the research supports the potential of urine-based energy systems as part of more sustainable wastewater treatment and resource recovery.
“Using urine as a resource supports sustainable sanitation and nutrient recovery, reducing pressure on freshwater systems,” he said.
The study, Investigating microbial interactions in dual chamber microbial fuel cells using a hybrid substrate of synthetic wastewater and human urine, was published in the journal Results in Chemistry. Research was supported by the Government of India’s Scheme for Promotion of Academic and Research Collaboration (SPARC).
