Researchers improve method to generate clean energy from human urine

Researchers have refined a technique that turns human urine into electricity, advancing a low-cost approach to both wastewater treatment and renewable energy generation.

A team of bioresource engineers at McGill University found that higher concentrations of urine significantly improve the performance of microbial fuel cells (MFC). MFCs are devices that use naturally occurring bacteria to break down organic waste while producing electricity.

The study helps answer a question that has limited progress in the field: How does urine concentration affect power output, pollutant removal and the behaviour of microbes inside the system?

“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 co-author Vijaya Raghavan, professor of bioresource engineering, in a statement. “Our work systematically examines how varying urine proportions affect both the microbes and the energy they produce.”

The research, titled 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. It was supported by the Government of India’s Scheme for Promotion of Academic and Research Collaboration.

Higher concentrations, stronger output

To test the system, researchers operated four dual-chamber microbial fuel cells using mixtures of synthetic wastewater and human urine at concentrations of 20 per cent, 50 per cent and 75 per cent. Over two weeks, they monitored electricity generation, pollutant removal and electrochemical activity.

Fuel cells using 50 per cent to 75 per cent urine produced the highest levels of electricity. According to the researchers, urine provides nutrients and ions that support microbial growth, which in turn improves both waste breakdown and energy production.

The team also observed changes in the microbial communities inside the cells. Sediminibacterium dominated at moderate concentrations, while Comamonas became more prevalent at higher concentrations. This shift may help explain differences in electrical output.

Because these microorganisms release electrons as they metabolise organic waste, the make-up of the microbial community directly influences how efficiently the system generates electricity.

Potential uses beyond the laboratory

The findings could have practical implications, particularly in places where conventional wastewater treatment is expensive or difficult to maintain, including rural sanitation systems, disaster relief settings and off-grid communities.

Researchers note that microbial fuel cells also produce electrical signals that vary with pollution levels. This means they could potentially function as low-cost biosensors, helping monitor wastewater quality without the need for complex laboratory equipment.

The study contributes to broader efforts to develop circular economy solutions that treat human waste as a resource rather than a disposal problem. Converting urine into electricity while recovering nutrients could help ease pressure on freshwater systems and reduce infrastructure costs.