In a creative breakthrough addressing both environmental pollution and waste management, Egyptian researchers have discovered that discarded eggshells—a ubiquitous byproduct of household and commercial kitchens—can effectively purify raw water from the Nile River.
The study, recently published in BMC Research Notes, found that processed eggshell waste can remove heavy metals and harmful bacteria from Nile water, Egypt’s main freshwater source.
This innovation comes at a critical moment for the country, which is facing mounting pressure on its already limited water resources due to rapid population growth, climate change, and industrial pollution. With the Nile providing more than 95% of Egypt’s freshwater supply, protecting its quality is essential for public health, food security, and economic resilience.
Led by scientists from the Faculty of Agriculture at Ain Shams University, the study explored the potential of eggshells as a natural filtration material. Researchers tested their ability to reduce concentrations of potentially toxic elements (PTEs)—including lead, cadmium, and iron—as well as microbial contaminants like Escherichia coli (E. coli), a common and dangerous indicator of fecal contamination.
The team collected raw water samples from the Nile near Helwan, an industrial district south of Cairo known for environmental degradation. Eggshells sourced from local bakeries were cleaned, dried, and ground into a fine powder. This eggshell waste (ESW) was then mixed with the water samples in controlled laboratory conditions.
The results were striking. The ESW removed up to 94.4% of lead, 64.7% of cadmium, and 51.4% of iron from the water. Even small amounts of these metals can cause serious health problems, including kidney damage and neurological disorders.
The eggshells also displayed strong antibacterial properties. Within just four hours, the concentration of E. coli was significantly reduced. After 24 hours of incubation at 37°C—the average human body temperature—no microbial contaminants remained in the treated samples.
Using Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX), researchers observed visible changes in the eggshells’ structure after treatment. These confirmed that the eggshells had successfully bound and absorbed the heavy metals and bacteria, highlighting their effectiveness as a low-cost bioadsorbent.
“This is a sustainable, circular solution that uses agricultural waste to address a pressing environmental issue,” the authors stated. “Eggshells are rich in calcium carbonate, which makes them ideal for capturing metals and microbes. The method is not only effective but also affordable and widely accessible.”
The implications are far-reaching, particularly for countries in the Global South where clean water is often scarce and water treatment infrastructure can be costly or unreliable. Egypt alone discards thousands of tons of eggshells each year—most of which end up in landfills. Repurposing this waste could help mitigate environmental degradation while improving access to safe drinking water.
The process requires minimal treatment and no hazardous chemicals, making it especially suitable for rural and low-income communities. The researchers suggest that, with proper collection and handling systems, eggshell-based treatment could be incorporated into both household and municipal filtration units.
Still, the team cautioned that more research is needed before the technique can be implemented on a wide scale. Future studies will need to assess the performance of eggshells in continuous flow systems, their interactions with other contaminants, and whether they can be reused or recycled after treatment. Collaborations with governmental agencies and environmental NGOs could help bring the technology from the lab to real-world applications.
“Our goal is to foster low-cost, community-driven innovations that are both effective and environmentally responsible,” the authors noted, expressing hope that their research will inspire further development in green technologies and waste valorisation.
