• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.1 s.20
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• pp.69-73
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• 2004

Control if Sediment is very important in prawn farm due to the eruption of toxic materials such as unionized $H_{2}S,\;NH_{3}\;and\;NO_3$. In this study, column test was conducted with filter media such as activated carbon, zeolite, oyster shell and iron chloride to evaluate the reduction of toxicity from sediment. ammonia-N($NH_3$) was effectively removed by Zeolite and oyster shell. It was indicated that ammonium ion($NH_4^+$) was removed by ion exchange of zeolite. And the ammonia in the column of oyster shell was existed as the form of $NH_4^+$, which is not toxic for prawn because oyster shell was stably kept at $8{\sim}9g$ of pH. Therefore, some of ammonia($NH_4^+$) was removed by oyster shell. Hydrogen sulfide and COD were effectively removed by adsorption of activated carbon and a partial removal of hydrogen sulfide was accomplished by Oyster shell. Phosphorous was removed by activated carbon, oyster shell and iron chloride. In prawn farm, the concentration of ammonia was increased with increase of pH by algae photosynthesis in the column of activated carbon, zeolite and iron chloride, but it was revealed that pH was stably kept in the column of oyster shell.

• Resources Recycling
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• v.11 no.2
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• pp.45-51
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• 2002

This study was performed to investigate removal efficiency of wastewater by the prepared coagulant using waste oyster shell and loess. Waste oyster shell and loess contain respectively high CaO(55.43% by weight), $SiO_2$(45.30% by weight). Waste oyster shell was calcined to improve the purity of CaO at the calcination condition of $900^{\circ}C$ for 2hours, and then crushed 0.074 mm(200mesh) size by ball mill. Also, coagulant was prepared with calcined waste oyster shell and loess powder by hydration reaction. Calcined waste oyster shell and loess powder were combined with mixing ratio of 6 : 4, 7:3, 8:2 and 9:1. Though comparison experiment between prepared coagulant and chemical )$Ca(OH_2$, prepared coagulant was proved as having replaceable possibility of chemical )$Ca(OH_2$in wastewater treatment plant.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.5
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• pp.281-286
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• 2005

The effect of oyster shell meal, which is made of a simple crushing and alkaline calcium materials, on soil microbial properties, microbial biomass C, N and P contents, and enzyme activities were evaluated in silt loam soil. The oyster shell meal fertilizer was added at the rates of 0, 4, 8, 12 and $16Mg\;ha^{-1}$. Microbial biomass C, N and P contents were significantly increased with increasing application of oyster shell meal. Soil enzyme activities, such as urease, ${\beta}$-glucosidase and alkaline phosphomonesterase were increased significantly by shell meal application, due to increased soil pH towards neutral range and increased nutrient availability in soil. In particular, the increased microbial biomass P content and phosphomonoesterase activities were strongly correlated with available P content in soil. Conclusively, oyster shell meal fertilizer could be a good supplement to improve soil microbial activities.

• Clean Technology
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• v.19 no.2
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• pp.90-94
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• 2013

We investigated one-dimensional thermal conduction for gypsum objects incorporating oyster shell powder. We presumed that according to the portion of oyster shell in the hybrid structure conductive characteristics of that would also change as some physicochemical properties such as volatile organic compound (VOC) adsorption were found to be changed considerably. Based on Fourier's 2nd law of heat conduction an analytical analysis in a flat slab (one axis perpendicular to an infinite plane) was performed. We found that composition of oyster shell and conduction-related coefficients and parameters could greatly influence on the thermal profile of that conduction, and some model experiments also served for it in the affirmative.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.30-36
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• 2006

This study was carried out to evaluate the performance of Modified Ludzsck Etinger (MLE) process with waste oyster shell media in aerobic tank. Influent flow was 36 L/d and the order of reactor was anoxic, aerobic and sedimentation tank and unit hydraulic retention time was 2 hr, 6 hr and 4 hr, respectively. Sludge recycling rate in sedimentation tank and internal recycling rate were 100%. Media fill rate in aerobic tank was 5%, 10% and 17% and fluid MLSS concentration in aerobic tank was 3000~4000 mg/L. Average TCOD removal rate was 91~93%, TBOD 92~96%, SS 95~96% and when media fill rate was 10% or more, in organic compound removal it could satisfy with wastewater discharge standard. Average total nitrogen removal rate was 70~76% and average total phosphorous removal rate was 58~65%. With media fill rate increasing, total phosphorous average removal rate also increased. For it was that released calcium ion from waste oyster shell reacted with soluble phosphorous. From these experiment results, the MLE process using waste oyster shell as media is a practical method for advanced sewage treatment in rural area.

• Journal of the Korean GEO-environmental Society
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• v.8 no.1
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• pp.27-32
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• 2007

Trafficability for construction equipments in soft ground should be secured by improving the surface course. For this situation, the ground improvement technique has been used with stiffening agent, but the improvement cement has been mostly used so far. However, oyster shell has been developed and used as the stiffening agent to expand the chance of recycling oyster shell, which is regarded as solid waste. In this research, it was confirmed mechanical characteristics of oyster shell as stiffening agent by analyzing the strength characteristic such as mixing rates, water contents, and curing days of that to the dredging soil.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.6
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• pp.125-134
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• 2010

This study was performed to evaluate the workability, strengths and durability of polymer concrete using oyster shell that are reclaimed at public shore illegally or leaved on the surroundings of shore to prevent the environmental pollution. We investigated the effect of oyster shell powder (OSP) and $CaCO_3$. on the slump, compressive strength, flexural strength, acid sulfuric and freezing and thawing resistance as a filler of polymer concrete. Modified OSP obtained by crushing oyster shell (less than 0.15 mm size) consists of 60.47 wt% of $SiO_2$ and 39.5 wt% of $CaCO_3$. As a result of slump test by OSP and $CaCO_3$. contents, it is found that slump of specimen used OSP is lower than that used $CaCO_3$. and the more OSP contents are, its slump is increased. Compressive and flexural strength of polymer concrete using OSP are similar or slightly lower than that using $CaCO_3$. In acid sulfuric test for 5 % $H_2SO_4$ and freezing thawing test, regardless of kinds of fillers and contents are not found fatal defects in weight change, falling-off in surface and durability factor.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.118-126
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• 2021

The experiments to produce the vaterite type calcium carbonate were conducted for using the waste oyster shell as the recycling resources. Firstly, the oyster shell were calcinated at 800 ℃ for 24 h. Calcinated oyster shell were reacted with the nitric acid solution, and were diluted to 0.1 M Ca(NO3)2 solution. This solution was mixed with 0.1 M Na2CO3 contained 0.1 mol lysine/1 mol CaO at 20 ℃ and 600 rpm mixing condition for 1 h. The reaction products were identified to vaterite type calcium carbonate (84.5% vaterite, 15.5% calcite) by XRD and SEM analysis. Mean particle diameter was 6.87 ㎛, and the lysine content in calcium carbonate was analyzed to 0.1%.

• 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.

• Preventive Nutrition and Food Science
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• v.15 no.1
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• pp.78-82
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• 2010

This study investigated the effects of water-soluble calcium supplements manufactured with eggshells and oyster shells on growing rats. The aim was to review the potential use of food wastes as materials for water-soluble calcium supplements as compared to water-soluble calcium supplements made from imported seaweed powder. When experimental animals were administered three types of water-soluble calcium supplements orally for six weeks, the serum calcium level of the seaweed calcium supplement group were significantly higher than that of eggshell or oyster shell-derived calcium, but blood alkali phosphatase activity, osteocalcin and urine crosslink levels were not different in the three types of calcium supplements. Bone mineral density and bone mineral content in spine, femur and tibia also were not significantly different among the groups. However, when considering body weight of each group, bone mineral density and bone mineral content of the femur were significantly higher in the oyster shell calcium supplement group. These results suggest that at least on a short-term basis, the effect of calcium supplements prepared from eggshell and oyster shell are similar to the effects of seaweed calcium supplements.