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How sea shells could be a source of sustainable biomaterials

A new study is shedding light on the economic value of mollusc shells. The seafood industry dumps over 7 million tons of the shells in landfills or in the sea every year. Researchers are developing plans that will put these biomaterials to good use.

Dr. James Morris and a team of CACHE researchers from the Royal Belgian Institute of Natural Sciences are exploring  environmentally and economically sustainable options for mollusc shells.

“Mollusc shells are viewed by the aquaculture and seafood industries as ‘nuisance waste’ and largely disposed of in landfills”, said Dr. Morris. “Not only is this an expensive and ecologically harmful practice, it is a colossal waste of potentially useful biomaterials”.

Dr. Morris and his team are proposing the use of discarded shells to redevelop damaged oyster reefs and cultivate the growth of new oysters. Oyster reef restoration is not expensive or difficult, and it provides invaluable ecological benefits.

“Healthy shellfish populations can have many benefits to the environment: cleaning the water, providing a complex structure for other organisms to call home, and also acting as a coastal protection structure,” explained Dr Morris.

Mollusc shells are over 95 percent calcium carbonate, and have many useful applications. Calcium carbonate can be used to develop cement mix and treat wastewater. It can also be fed to hens as a calcium supplement and used by farmers to control soil acidity.

Limestone mining is the world’s main source of calcium carbonate, and it is not an environmentally friendly or sustainable practice. Dr. Morris and his team hope to reduce limestone mining by recycling mollusc shells as a secondary source of calcium carbonate.

“Reusing shell waste is a perfect example of a circular economy, particularly as shells are a valuable biomaterial, not only does it improve the sustainability of the aquaculture industry moving forwards, but it can also provide secondary economic benefits to shellfish growers and processors as well,” said Dr. Morris.

Dr. Morris believes eliminating tons of mollusc shell waste every year will be advantageous in many ways.

“The proper disposal procedure for shell waste is in landfill, which costs a lot of money and can be a big burden for shellfish farmers and seafood producers,” said Dr Morris.”Simply finding a use for shells to avoid taking them to a landfill already has economic value!”

By Chrissy Sexton, Staff Writer

Source: Royal Belgian Institute of Natural Sciences

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