• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.146-147
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• 2013

The oyster shells of about 240,000 tons have been annually produced in south coast of South Korea. However, about 25% of the oyster shells (60,000tons) was recycled as oyster seeding and fertilizer due to the limited amount of consumption for such purposes. The stored amount of oyster shell in the fertilizer manufacturing company is overfilled, and thus cannot accept any more of the waste oyster shells. As a result, landfill and illegal dumping of waste oyster shells have become an increasingly serious issue since 2011. In this research, the problems generated by the oyster shells were investigated through surveying activities. One of the possible alternative solutions that can process large amount of waste economically was found to be the application of oyster shells as a construction materials.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.133-138
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• 1997

The technology of removing phosphorous, considered as one of the most important control nutrients causing eutrophication in various water bodies, have been investigated by many researchers. Recently, phosphorous crystallization process is emerging as a new technology for phosphorous removal. In this study, waste oyster shells which can be easily obtained from the ocean, were used as a seed crystal, and their effects of several physical/chemical factors on the phosphorous removal efficiencies were examined by batch tests. Ca$^{2+}$ and pH affected phosphorous crystallization process using waste oyster shells. As alkalinity of wastewater increased, phosphorous removal efficiencies gradually decreased. Phosphorous removal efficiencies were increased, as specific area and contact efficiency per unit area of waste oyster shells were increased. In case of high temperature, phosphorous crystallization process was rapidly advanced and phosphorous removal efficiencies were increased. Dependig on X-ray diffraction analysis, it was showed that generation materials extracted from the surface of waste oyster shells with short reaction time were dominated by $CaHPO_4\cdot 2H_2O$, but progressed to $Ca_5(OH)(PO_4)_3$. The SEM observation reveals that the evident variations were hardly seen, but particle sizes of waste oyster shells were relatively bigger and showed forms of smaller plate than before.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.427-436
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• 2010

Much oyster shell is breeding by character and conduct of oyster-industry for a long time among them. An experimental study was carried out to investigate the recycling possibility of waste oyster shells, which induce environmental pollutions by piling up out at the open or the temporary reclamation. The purpose of this study is to develope eco-friendly binder using waste oyster shells, and to reinforce soils fur soft soil improvement. In this paper, a series of laboratory tests including compressive pot tests were performed to evaluate characteristics of soils treated by developed waste oyster shells with different water content of soils. Based on test results, eco-friendly Supporter manufactured from waste oyster shells were estimated as good resource materials for soft soil improvements. We got the conclusion by a series of experiment, It is verified that change of pH of soil is improved by mixing with oyster shells. The homogenization method for deducing apparent of oyster shells, which can consider micro-structure of mixed soil, is introduced. The improvement treatment leaded to enlarge fluctuation of soil moisture content. The effect of calcium concentration was good though improvement treatment of physical property. In addition, the crop yield in amelioration plots increased. It means that the increase of crop yield was caused by improvement of soil physical properties rather than improvement of calcium concentration.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.17-21
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• 2001

The object of this study is to find out the characteristics of waste oyster shells and determine the proper dosage of powdered waster oyster shells as the conditioning agent for water treatment sludge dewatering process. The large amount of waste oyster shells which discharges from the oyster farming, occurs serious environmental hazards. However, oysters shell contain large amount(about 38% by weight) of alkaline minerals, such as calcium and magnesium and so on, this natural material is thought to have the petential ability as a good conditioning agent. The results of this study are as follows. The optimum condition for improvement of the water treatment sludge dewaterability is when 6 g of waste oyster shell powder added to 200$m\ell$ of water treatment sludge. At optimum condition, the solid contents can reach to 31.78% and the specific resistance of conditioned sludge is 0.16$\times$10$^{8}$ sec$^2$/g. However, exceeding the of powdered waste oyster shell is needed to get the effective result. Consequently, the waste oyster shell can be a recyclable material to improve the dewaterability of water treatment sludges.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.208-209
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• 2014

Recently, many environmental problems occur due to the waste shells in South Korea. In case of oyster and cockle, utilizing waste shells to produce fertilizer once also, but due to sluggish consumption, production is no longer difficult. The stored amount of waste shells in the fertilizer manufacturing company is overfilled, and thus cannot accept any more of the waste shells. As a result, landfill and dumping of waste shells have become an increasingly environmental problems. In this research, the basic physical properties and interfacial bonding form of the mortar mixed with waste shells (manila clam, cockle, clam, sea mussel, oyster) were evaluated.

• The Journal of Fisheries Business Administration
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• v.51 no.2
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• pp.71-87
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• 2020

Oysters are the most abundantly harvested type of shellfish in Korea. As export of this marine product increases, oysters have greatly contributed to an increase in fishing income. As the oyster aquaculture industry has rapidly grown since the late 1990s, issues of oyster-shell processing that occur in production processes have re-emerged as important topics in the oyster industry. The amount of oyster shells harvested in 2019 is estimated to be approximately 300,000 tons. With reductions in demand for pyrolytic fertilizer and feed, which are currently the greatest sources of demand, unprocessed shell quantities have doubled compared to 2018, causing them to be an issue once more. Such oyster-shell processing also incurs great costs, and a total of forty-six billion three hundred fifty million Korean won (46,350,000,000 KRW) has been provided from 2009 to 2020 for the use of oyster shells as a resource. According to current Korean laws, oyster shells are considered to be industrial waste if more than 300 kilograms are sent out in a day. Collection and processing must be conducted by a waste-consignment company. Consequently, there are many limitations to the use of oyster shells in Korea as a resource. However, in Japan, only oyster-shell waste is regulated by waste-processing As a result, local governments may apply exceptions when utilized as organic matter. Consequently, in Japan, oyster shells are being used as resources in more diverse fields than in Korea. This study observes the conditions and problems of oyster-shell processing in Korea and attempts to find new domestic oyster-shell resource solutions in light of Japan's recycling practices.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.524-528
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• 2010

In this study, the structure and properties of waste oyster shell and its phosphorus removal efficiency were investigated. Waste oyster shells are troublesome environmental waste in the coastal region where the oysters are produced. Waste oyster shells were pyrolyzed by bench-scale rotary kiln for its activation. It shows maximum 76% of phosphorus removal efficiency for the municipal wastewater and livestock wastewater. We found that the activated oyster shells can be used as a phosphorus removal agent with the consideration of high efficiency, easy processing, and cost effectiveness.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.148-149
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• 2013

Recently, the construction industry in South Korea, has experienced many difficulties in lack of supply with construction materials. Since waste shells can be possibly used as replacement materials of fine aggregate, the successful application can resolve, to some extent at least, the economic problems and environmental problems. In this research, the basic physical properties of the mortar which was used as fine aggregate substitute (clam, cockle, manila clam, oyster) were evaluated. According to the experimental results, the absorption rate and compressive strength of samples with various shells were equivalent to that of plain mortar. The mortar which replaced 25% of oyster shell with sand showed approximately 30% lower compressive strength and twice as much absorption as plain mortar. It was found that waste shells can be used as replacement materials of fine aggregate, but the oyster shell requires further experimental works in order for its successful application.

• Journal of Energy Engineering
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• v.27 no.1
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• pp.59-64
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• 2018

In this paper, we investigated the alternative sources of limestone. Oyster shell waste originated from aquaculture that causes a major disposal landfill problem in coastal sectors in southeast Korea. Their inadequate disposal causes a significant environmental problems araised. Bio mineralization leads to the formation of oyster shells and consists $CaCO_3$ as a major phase with a small amount of organic matter. It is a good alternative material source instead of natural lime stone. The utilization of oyster shell waste for industrial applications instead of natural limestone is major advantage for conservation of natural limestone. The present work describes the limestone and oyster shells hydraulic activity and chemical composition and characteristics are most similar for utilization of oyster shell waste instead of natural limestone.

• Journal of the Korean Geotechnical Society
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• v.21 no.3
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• pp.79-85
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• 2005

An experimental study was carried out to investigate the recycling possibility of waste oyster shells, which induce environmental pollutions by piling up out at the open or the temporary reclamation. The purpose of this study is to develope eco-friendly binder using waste oyster shells, and to reinforce dredged soils fur soft soil improvement. In this paper, a series of laboratory tests including compressive strength tests were performed to evaluate strength characteristics of soils treated by developed binder with different water content of dredged soils, mixing rates of binder, curing days. Based on test results, eco-friendly binders manufactured from waste oyster shells were estimated as good resource materials for soft soil improvements.