• 대한환경공학회지
• /
• 제29권1호
• /
• pp.82-88
• /
• 2007

용존공기부상법과 중력침전법을 이용하여 제지공장의 팽화슬러지를 농축에서 폐 굴패각 분말을 첨가제 사용하였을 때의 효과를 조사하였다. 굴패각의 투입량과 크기분포와 같은 인자가 연구되었다. 혼합 굴패각(크기 범위 : $\sim250{\mu}m$)의 최적 투입량은 0.8 g/L인 것으로 나타났다. 침전공정에서 굴패각 5.0 g/L 첨가시 농축 슬러지 농도는 3.25배 증가하였다. 용존공기부상법에서 5.0 g/L의 굴패각 첨가시 Buckler funnel test 장치를 이용하여 측정한 슬러지의 함수율은 95.5%에서 82.7%로 감소되었다. 혼합 굴패각을 4가지 크기($\sim53{\mu}m$, $53\sim106{\mu}m$, $106\sim150{\mu}m$, $150\sim250{\mu}m$)로 나누었을 때 부상과 탈수공정에서 최적 굴패각 입도 범위는$53\sim106{\mu}m$로 나타났다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2020년도 봄 학술논문 발표대회
• /
• pp.64-65
• /
• 2020

Oyster shells are difficult to grind, while oyster shell powders have coarse and coarse grains, whereas egg shell powder, the same high calcium material, has small and soft particles and has opposing properties. In order to study the change in flexural and compressive strength by designing different mixing ratios using 50% of oyster shell powder and egg shell powder as a filling material. As a result of the experiment, there is almost no difference in the result.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2005년도 춘계 학술발표회 논문집
• /
• pp.553-560
• /
• 2005

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

• 한국환경과학회지
• /
• 제18권2호
• /
• pp.205-213
• /
• 2009

A laboratory experiment was conducted to investigate nitrogen removal from plating wastewater by a soil reactor. A combination of soil, waste oyster shell and activated sludge were used as a loading media in a soil reactor. The addition of 20% waste oyster shell and activated sludge to the soil accelerated nitrification (88.6% ${NH_4}^{+}-N$ removal efficiency) and denitrification (84.3% ${NO_3}^{-}-N$ removal) in the soil reactor, respectively. In continuous removal, the influent ${NH_4}^{+}-N$ was mostly converted to nitrate nitrogen in the nitrification soil reactor and only a small amount of ${NH_4}^{+}-N$ was found in the effluent. When methanol was added as a carbon source to the denitrification soil reactor, the average removal efficiency of ${NO_3}^{-}-N$ significantly increased. The ${NO_3}^{-}-N$ removal by methanol addition in the denitrification soil reactor was mainly due to denitrification. The phosphorus was removed by the waste oyster shell media in the nitrification soil reactor. Moreover, the phosphorus removal in the denitrification soil reactor was achieved by synthesis of bacteria and the denitrification under anaerobic conditions. The approximate number of nitrifiers and denitrifiers was $3.3{\times}10^5\;MPN/g$ soil at a depth of $1{\sim}10\;cm$ and $3.3{\times}10^6\;MPN/g$ soil at a depth of $10{\sim}20\;cm$, respectively, in the soil reactor mixed with a waste oyster shell media and activated sludge.

• 대한환경공학회지
• /
• 제31권12호
• /
• pp.1095-1104
• /
• 2009

본 연구는 오염토양 정화 및 폐자원의 재활용 측면에서 굴껍질 및 달걀껍질을 활용한 비소 오염토양 안정화 기술의 적용 가능성을 평가하고자 수행되었다. 안정화 효율을 평가하고자 5가비소로 오염된 토양에 굴껍질과 달걀껍질을 0%(무처리구)~5% 수준으로 처리한 후 30일간 항온배양 하였으며 이후 1 N HCl, 0.1 N NaOH, 0.5 N $H_2SO_4$의 추출제를 이용하여 토양 중 비소를 추출하였다. 1 N HCl 추출결과 무처리구의 비소 함량은 29.43 mg/kg였고 굴껍질 5% 및 달걀껍질 5% 처리구에서 각각 26.26 mg/kg와 26.74 mg/kg로 나타나 평균 10% 정도로 감소효과를 나타내었다. 이외 0.1 N NaOH 및 0.5 N $H_2SO_4$ 추출결과에서도 비소의 농도는 소폭 감소하였다. 한편 굴껍질 및 달걀껍질 처리 토양의 pH는 7.62~7.94로 무처리구 (pH 6.54)에 비해 pH 1 이상 증가하였고, 토양 내 치환성 칼슘의 함량은 12.77~20.18 cmol(+)/kg로 무처리구(6.87 cmol(+)/kg)보다 약 2배 이상 증가하는 것으로 나타나 굴껍질과 달걀껍질은 토양 비옥도 개선에 효과가있는 것으로 판단되었다. 이상의 결과를 종합해보면 굴껍질과 달걀껍질의 직접적 사용은 토양의 비옥도 향상에는 효과가 있는 것으로 판단되나 토양내 비소의 안정화에 적용하기에는 다소 부적합한 것으로 판단되며 향후 효율성 향상을 위하여 소성과 같은 적절한 가공 공정이 필요한 것으로 판단되었다.

• 한국환경보건학회지
• /
• 제23권4호
• /
• pp.133-138
• /
• 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.

• 시멘트 심포지엄
• /
• 27호
• /
• pp.6-13
• /
• 2000

• 한국지반환경공학회 논문집
• /
• 제8권1호
• /
• pp.27-32
• /
• 2007

연약지반과 관련된 공사에서는 표층을 개량하여 교통성을 확보하여야 한다. 이를 위해 고화재를 이용한 지반개량공법이 이용되고 있으나, 지금까지 사용된 고화재는 시멘트를 개량한 제품을 이용하였다. 그러나 현재 폐기물로 인정되는 굴패각의 재활용 기회를 확대하기 위해 굴패각을 이용한 고화재를 개발하여 사용하고 있다. 본 연구에서는 준설토를 대상으로 굴패각 고화재의 혼입율, 함수비, 양생일에 따른 강도 특성을 분석하여 굴패각 고화재의 역학적 특성이 우수함을 확인하였다.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2001년도 지반환경 및 준설매립에관한 학술세미나
• /
• pp.72-84
• /
• 2001

In order to utilize mass of oyster shells for a partial substitute material for reclamation, we investigate the shear characteristics of dredged sluge mixed with oyster shells. the apparent modulus of elasticity of the this mixture are obtained from the triaxial compression tests and is utilized to characterize the apparent modulus of elastic of the oyster shells by carrying out some numerical analysis based upon the homogenization theory. We got the conclusion by a series of experiment, 1) It is verified that modulus of elasticity of dredged clay is improved by mixing with oyster shells. 2) The homogenization method for deducing apparent modulus of elasticity of oyster shells, which can consider micro-structure of mixed soil, is introduced. The elastic modulus is affected from the skeleton structure of oyster shell. The effect of 49kPa is bigger than that of 98kPa.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제10권S_2호
• /
• pp.79-88
• /
• 2001

Humic acids react with chlorine to produce Trihalomethanes(THMs), known as carcinogens, during disinfection, the last stage in water purification. Currently, the removal of organic humic acids is considered the best approach to solve the problem of THM formation. Accordingly, the current study examined the adsorption of organic compounds of humic acids onto an inorganic carrier prepared from oyster shell waste. The adsorbent used was activated oyster shell powder(HAP) and silver ion-exchanged oyster shell powder(HAP-Ag), with CaCO$_3$ as the control. The adsorbates were phthalic acid, chelidamic acid, catechol, dodecylpyridinium chloride(DP), and 2-ethyl phenol(2-EP). The adsorption experiments were carried out in a batch shaker at $25^{\circ}C$ for 15 hours. The equilibrium concentration of the adsorbate solution was analyzed using a UV spectrophotometer and the data fitted to the Langmuir isotherm model. Since the solution pH values were found to be greater than the pKa values of the organic compounds used as adsorbates, the compounds apparently existed in ionic form. The adsorptive affinities of the organic acid and phenolic compounds varied depending on the interaction of electrostatic forces, ion exchange, and chelation. More carboxylic acids and catechol, rather than DP and 2-EP, were adsorbed onto HAP and HAP-Ag. HAP and HAP-Ag exhibited a greater adsorptive affinity for the organic compounds than CaCO$_3$, used as the control.