“Calcined Eggshell Powder as a Low-Cost Adsorbent for Phosphate Removal from Simulated Urban Runoff” by Maya Patel
- May 14
- 4 min read
Updated: May 18
Article Title: Calcined Eggshell Powder as a Low-Cost Adsorbent for Phosphate Removal from Simulated Urban Runoff
Author: Maya Patel
Date Published: May 13, 2026
Publication: Agora Review
Category: Research Article
Discipline(s): Environmental Chemistry, Sustainability Science
Keywords: phosphate removal, eggshell waste, adsorption, eutrophication, urban runoff, calcium carbonate, water treatment, circular economy
Suggested Citation: Patel, Maya. “Calcined Eggshell Powder as a Low-Cost Adsorbent for Phosphate Removal from Simulated Urban Runoff” Agora Review, May 13, 2026.
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Abstract
Excess phosphorus in freshwater systems is a major contributor to eutrophication, a process that can lead to algal blooms, oxygen depletion, fish mortality, and reduced water quality. Although advanced wastewater treatment systems can remove phosphorus effectively, many low-cost and decentralized treatment options remain limited. This study investigated whether calcined chicken eggshell powder, a calcium-rich food waste material, could remove phosphate from simulated urban runoff under laboratory conditions. Waste eggshells were cleaned, dried, ground, and heated at 800 °C to convert calcium carbonate-rich shells into a more reactive calcium oxide-containing material. Batch adsorption experiments were conducted using potassium dihydrogen phosphate solutions at an initial phosphate concentration of 5.0 mg/L as PO₄³⁻. The effects of adsorbent dosage, contact time, and pH were evaluated using a colorimetric ascorbic acid method measured by visible-light spectrophotometry. Calcined eggshell powder removed phosphate more effectively than uncalcined eggshell powder across all tested conditions. At an adsorbent dose of 2.0 g/L, calcined eggshell powder reduced phosphate concentration from 5.02 ± 0.06 mg/L to 1.14 ± 0.09 mg/L after 120 minutes, corresponding to 77.3% removal. Removal was strongest under near-neutral to slightly alkaline conditions, with lower efficiency observed at pH 5 and pH 10. The results suggest that calcined eggshell powder may provide a simple, low-cost approach for phosphate reduction in small-scale or preliminary water treatment applications. However, the findings should be interpreted cautiously because the study used simulated runoff rather than real stormwater and did not evaluate long-term regeneration, competing ions, or large-scale performance. Overall, this experiment supports the potential value of converting food waste into functional materials for nutrient pollution control.
Author’s Note
This project began with a small observation from daily life: how many eggshells are thrown away every week in ordinary households, bakeries, and cafeterias. At first, I thought of eggshells only as food waste. However, after learning that eggshells are composed mostly of calcium carbonate, I became curious about whether they could be repurposed for environmental applications rather than discarded. Around the same time, I was reading about eutrophication and the way excess nutrients from fertilizers, detergents, wastewater, and runoff can damage lakes and rivers. The connection between these two issues—food waste and water pollution—made me wonder whether one waste problem could help address another.
Phosphate pollution is especially important because it is not always visible at first. Unlike an oil spill or floating plastic, dissolved nutrients may enter a water body quietly, but their effects can become serious once algal blooms develop and oxygen levels decline. This made the topic feel both scientifically interesting and socially relevant. I was particularly drawn to the idea that sustainability does not always require highly advanced or expensive technologies. Sometimes, useful solutions may come from rethinking materials that are already available.
In this study, I wanted to test a simple question in a systematic way: can calcined eggshell powder remove measurable amounts of phosphate from water under controlled conditions? The experiment was not intended to prove that eggshell powder could replace conventional wastewater treatment. Instead, it was meant to explore whether a low-cost waste-derived material could show enough promise to justify further research.
I hope this paper encourages readers to think more creatively about the relationship between waste, chemistry, and environmental design. Materials that appear useless in one context may become valuable in another if their chemical properties are understood and applied carefully. More broadly, I hope the project contributes to discussions about circular economy thinking: the idea that environmental solutions should not only reduce pollution, but also find better uses for materials that would otherwise be discarded.
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