The 'Problem Child' of Coastal Areas, Useful After Treatment... Developing Methods to Utilize Oyster Shells, a Headache for Scenery and Water Quality

Development of Coastal Environment Restoration Technology Using Heat-Treated Oyster Shells
Pukyong National University Completes Demonstration Study on Sediment Improvement through Pretreatment Technology

The image shows heat-treated oyster shells being dispersed into the sea.

[Asia Economy Yeongnam Reporting Headquarters Reporter Kim Yong-woo] What to do with oyster shells, a coastal nuisance that damages the scenery and pollutes the water quality?

A research result has attracted attention, showing that the coastal "problem child," the fishery byproduct "oyster shells," can be recycled to restore the coastal environment.

The Yeongnam Sea Grant Center at Pukyong National University (Director Lee Seok-mo) announced on the 1st that it has completed a demonstration experiment to solve the research project "Development of Coastal Ecological Space Restoration Technology Using Oyster Shells" (Principal Professors Lee In-cheol and Kim Kyung-hoe of the Department of Ocean Engineering).

Oysters, mainly farmed in the Gyeongnam region, are actively consumed and exported overseas, but nearly half of the 300,000 tons of shells generated annually remain untreated and are stockpiled along the coast, causing marine water pollution and landscape damage. Tens of billions of won are spent annually on oyster shell disposal.

In this research project, the center developed a technology to fundamentally solve the oyster shell problem by lowering the recycling processing cost and utilizing it for coastal ecological space restoration.

The newly developed technology lowers recycling processing costs by applying a heat treatment method at a relatively low temperature of 700 degrees Celsius instead of chemically treating oyster shells.

Since June, the center has monitored water quality, sediment, and benthic organisms for five months after covering a 100㎡ area near an oyster farm in Tongyeong, Gyeongnam, with a 10 cm thick layer of heat-treated oyster shells over contaminated sediment.

Pukyong National University captured and released photos showing the murky sea before oyster shell spreading (left) and the improved water quality after spreading (right).

The experiment results showed that the concentration of phosphate in seawater (pore water) within the sediment and in the overlying seawater decreased by about 40%. Notably, a decrease in anaerobic microorganisms and a significant increase in benthic organism biomass within the sediment were observed.

Professor Kim Kyung-hoe of the Department of Ocean Engineering said, "Oyster shells can significantly reduce the concentration of phosphate, a substance that greatly influences red tide occurrence, which is expected to help reduce red tide damage, restore benthic ecosystems, and consequently increase fishery resources, thereby improving fishermen's income."

The center has been conducting the research project since 2017 with support from the Korea Institute of Marine Science and Technology Promotion under the Ministry of Oceans and Fisheries, and obtained these research results through this year's demonstration experiment.

This content was produced with the assistance of AI translation services.