Seashells: A Natural Solution to Water Quality Problems
- “Water is critical to life, and many people in the developing world suffer because of a lack of fresh clean water.”
It is estimated that 3 in 10 people in the world lack access to safe drinking water services and 6 in 10 people lack access to safe sanitation facilities. Water scarcity is being driven by climate change and increased demand due to a rising population and agriculture.
Although global attention has focused primarily on water quantity, water-use efficiency and allocation, poor wastewater management has created serious water-quality problems in many parts of the world, worsening the water crisis.
Top 3 questions we receive about water purification:
- What are the solutions of water pollution?
- How to reduce water pollution?
- How can we fix water quality?
Seashells can be used to solve a range of water quality problems with little impact on the environment and human health:
Seashells and Conventional Water Purification
Conventional water purification methods include chemical precipitation, coagulation, flocculation, ion exchange, membrane filtration, activated carbon and other high-cost technology (such as the use of carbon nanotubes). One of the most effective methods of tertiary treatment is the photocatalysis of water to remove any final trace contaminants. This process normally uses titanium dioxide, which is expensive and not affordable in many developing country situations. Replacing titanium dioxide with hydroxyapatite from the calcium derived from seashells could significantly reduce the cost of water treatment by reusing a renewable unwanted waste product.
Collecting and treating domestic wastewater is essential to protect human health and the environment. A project in Taiwan has developed a system to treat domestic wastewater using oyster shells. The system uses three horizontal flow tanks. There are three horizontal flow tanks in this system, a horizontal flow and aerated oyster shell tank (HAOS), a horizontal flow oyster shell tank (HOS), and a horizontal flow gravel tank (HG). Domestic wastewater is often contaminated with organic matter and the BOD5 (Biochemical Oxygen Demand) is a standard measure used to assess organic matter content. The study found that It was found that oyster shells were more efficient at reducing BOD5 levels than using gravels.
Biofilters are becoming an increasingly popular treatment device for odours and other volatiles found at wastewater treatment plants. A seashell based biofilter was installed in April 2011 at Lake Wildwood Wastewater Treatment Plant in California and is reported to be successful at removing odorous sulphur compounds to a level of greater than 99%, effectively eliminating any odour.
Farms discharge large quantities of agrochemicals, organic matter, drug residues, sediments, and saline drainage into water bodies. The livestock sector is growing and the associated waste, including manure, has serious implications for water quality.
Seashells can contribute to managing waste from intensive livestock farms. Work in Japan on wastewater from pig farms attempted to develop a phosphorus removal technique using natural calcareous materials whose products can be restored to farmland as phosphate materials with minimal waste, at a low cost and with easy management.
Heavy Metal Contamination
Heavy metals are among the most common pollutants found in wastewater. These metals pose a toxicity threat to human beings and animals even at low concentration. Effective treatments of industrial waste streams and toxic spills containing heavy metals depend on the rapid removal of high concentrations of metal ions, this can be done using minimally processed waste mollusc and crustacean exoskeletons. Seashells can rapidly absorb metal ions. A solution with a lead content of 10,000 mg per litre, for example, can be reduced to less than about 0.5 mg per litre in five minutes using clamshells. At higher initial concentrations, both clam and oyster shells can extract almost twice their weight of lead. The uptake mechanism involves the exchange of Ca for Pb in the inorganic fraction of the shell structure.
A recent study looked at the potential of Moroccan seashells as a natural absorbent and found they were able to absorb 4.05 mg of nickel per gram. Increased temperature can improve the ability of seashells to remove metal contaminants. It has been found that natural aragonite, NA, (in the form of crushed seashells) can remove 22.5% of copper from an aqueous solution at 25°C but this is increased to 83.5% at a temperature of 50°C.
Solution to fix water quality
There is a growing need for affordable and natural solutions to water quality issues around the world and seashells can play a role in providing clean water for human needs and in safeguarding the environment.
Where to buy seashells?
Morgan Agro provide the highest quality seashells from the Caspian Sea. The product is great for use in a range of applications, including the treatment and purification of wastewater from a wide range of sources and industries. Click here to contact us.
- UN, “Goal 6: Ensure Access to Water and Sanitation for All,” UN Sustainable Development Goals, 2021.
- Javier Mateo-Sagasta, Sara Marjani Zadeh, and Hugh Turral, “Water Pollution from Agriculture: A Global Review,” Executive Summary, 2017.
- Maureen Gaines, “Seashells Offer ‘significant Savings’ for Wastewater Treatment,” Water Industry Asset Management, 2013, https://wwtonline.co.uk/news/seashells-offer-significant-savings-for-wastewater-treatment#:~:text=Seashells left over from restaurants,scaled up to industrial level.
- Pollutec, “How Should BOD5 Be Used in Biological Wastewater Treatment?,” 2020, http://blog.pollutec.com/en/how-should-bod5-be-used-in-biological-wastewater-treatment/.
- BOD5 is a measure of organic matter used in municipal waste water management.
- Po Kang Shih and Wen Lian Chang, “The Effect of Water Purification by Oyster Shell Contact Bed,” Ecological Engineering, 2015, https://doi.org/10.1016/j.ecoleng.2015.01.014.
- Samantha Abraham, Scott Joslyn, and I. H.(Mel) Suffet, “Treatment of Odor by a Seashell Biofilter at a Wastewater Treatment Plant,” Jounal of the Air and Waste Management Association, 2015, https://doi.org/10.1080/10962247.2015.1075918.
- Mateo-Sagasta, Zadeh, and Turral, “Water Pollution from Agriculture: A Global Review.”
- Makoto Takeuchi and Michio Komada, ‘Phosphorus Removal from Hoggery Sewage Using Natural Calcium Carbonate’, Japan Agricultural Research Quarterly, 1998.
- Helen E A Tudor, Carl C Gryte, and Colin C Harris, “Seashells: Detoxifying Agents for Metal-Contaminated Waters,” Water, Air, and Soil Pollution 173, no. 1 (2006): 209–42, https://doi.org/10.1007/s11270-005-9060-3.
- Helen E A Tudor, Carl C Gryte, and Colin C Harris, ‘Seashells: Detoxifying Agents for Metal-Contaminated Waters’, Water, Air, and Soil Pollution 173, no. 1 (2006): 209–42, https://doi.org/10.1007/s11270-005-9060-3.
- Mohamed Allaoui et al., “Study of the Adsorption of Nickel Ions on the Sea Shells of Mehdia: Kinetic and Thermodynamic Study and Mathematical Modelling of Experimental Data,” Materials Today: Proceedings, 2021, https://doi.org/https://doi.org/10.1016/j.matpr.2021.02.234.
- Ahmad Baraka et al., “Alkaline Treatment of Seashells and Its Use for the Removal of Cu(II) from Aqueous Solution,” Desalination and Water Treatment, 2010, https://doi.org/10.5004/dwt.2010.1047.