Researchers at the University of Birmingham have demonstrated that a tertiary wastewater treatment technology based on Daphnia — tiny freshwater organisms commonly known as water fleas — can deliver environmental benefits compared with conventional treatment methods.
In a study published in Water Research, the team found that treating one cubic meter of water with the Daphnia-based system produces just 0.0006 kilograms of CO₂, representing a 99.8% reduction in climate emissions relative to standard tertiary treatment technologies. At the scale of a typical installation processing 100,000 cubic meters of water annually, the approach could avoid more than 30 tons of CO₂-equivalent emissions each year, with proportionally larger savings for higher-capacity systems.
The technology relies on natural biological filtration rather than energy-intensive processes or chemical additives, resulting in minimal land requirements and very low solid waste generation.
Beyond carbon reductions, the researchers conducted a full life cycle assessment to evaluate the system’s broader environmental footprint, including impacts often overlooked in conventional analyses. By explicitly accounting for persistent, mobile and toxic chemicals such as pharmaceuticals, pesticides and industrial compounds, the study shows that the Daphnia-based system significantly reduces chemical pollution associated with long-term risks to ecosystems and human health.
Residual solids generated during treatment are minimal and can be converted into reusable biochar, further reducing waste. The researchers note that by removing excess nutrients, suspended solids and harmful micropollutants, the technology also helps curb eutrophication and protect freshwater biodiversity. The findings suggest that nature-based solutions like Daphnia biofiltration could offer wastewater utilities a scalable, low-cost pathway to meet tightening environmental regulations.