• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.09a
• /
• pp.122-124
• /
• 2002

The removal capacity of zero-valent iron for Cr(Ⅵ) was evaluated using batch kinetic tests. The rate constants for zero-valent iron dramatically increased as initial Cr(Ⅵ) concentration decreased. Generally, the reaction rates of Cr(Ⅵ) with zero-valent iron were faster than that of a biotic degradation of Cr(Ⅵ), and furthermore the reaction rates were inversely proportional to the initial Cr(Ⅵ) concentrations. After certain reaction time elapsed. no further decrease of Cr(Ⅵ) was observed, indicating a loss of iron reactivity. The loss of iron reactivity was primarily due to the passivation of iron surfaces with iron-Cr precipitates, but the reactivity of iron was recovered by adding iron-reducing bacteria. Even though the addition of bacteria itself removed Cr(Ⅵ), the combination of iron-reducing bactera and oxidized iron significantly enhanced the reaction rate for Cr(Ⅵ) removal. The results from column tests also confirmed that the innoculation of iron-reducing bacteria to the column containing completely oxidized iron partially enhanced the recovery of the iron reactivity.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2006.04a
• /
• pp.41-44
• /
• 2006

The objective of this study was to evaluate the stabilization of As and heavy metals in tailings from the Samkwang Au-Ag mine with $Ca(OH)_2$. In order to evaluate the stabilization ability of As and heavy metals in the tailings, column test was implemented with various conditions as 1) particle size of $Ca(OH)_2$, 2) mixing method and 3) flow rate of eluents during 60 days. The results showed that addition with 5% of $Ca(OH)_2$ in 1kg of the tailings had the most effective ability of stabilization up to 95%. In addition, stabilization ability of As and heavy metals in tailings was enhanced using a fine powder of $Ca(OH)_2$. Therefore, stabilization technology can be used as a remediation of As and heavy metals in mine wastes including tailings and a nearby soils from abandoned metal mines.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1996.11a
• /
• pp.97-101
• /
• 1996

산림부산물인 수피에 의한 카드뮴 이온의 선택적 흡착 현상을 이용하여 인공폐수로부터 카드뮴이온의 제거를 시도하였다. 카드뮴 이온 선택성이 우수한 소나무와 상수리 나무의 수피를 이용한 효율적인 연속식 대량 수처리 시스템의 개발을 위한 기초 실험으로 카드뮴 이온흡착 등온선을 조사하였고, batch stirred reactor, airlift reactor, packed bed column 등 여러 접촉시스템에서의 카드뮴 이온의 제거 효율을 검토하였다. 카드뮴 흡착등온선은 두 수피 모두 Langmuir 형식으로 나타났으며 소나무 수피의 최대흡착용량은 약 7 mg/g, 상수리나무 수피의 경우에는 약 8 mg/g 정도로 나타났다. Batch stirred reactor를 이용한 시스템에서 초기농도 13 ppm의 카드뮴용액 100 $m\ell$ 을 수피 10 g 과 접촉시킨 결과 30분 이내에 95% 이상 제거되는 효율성을 보여주었다. Airlift reactor를 이용한 시스템에서는 수피 30 g 을 포기농도 10 ppm 카드뮴 용액 1 liter와 접촉시킨 결과 15분 이내에 93 % 이상 제거되었으며 4 cycle 반복 운전에서도 거의 같은 성능을 유지하였고 그 이상의 cycle에서는 점점 성능이 떨어짐을 보여주었다. Packed bed column을 이용한 시스템에서는 20 g의 수피를 충전시켰을 경우 초기농도 20 ppm에서 effluent 2.5 liter 까지는 95% 정도의 제거효율을 보여주었다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.11a
• /
• pp.209-212
• /
• 2000

As a bench-scale study, transformation of nitrate to nitrogen gas under anoxic condition was determined by using autotrophic denitrifiers containing Thiobacillus denitrificans and elemental sulfur as an electron donor. The research objective is to measure the basic kinetic parameters of autotrophic denitrification reaction on the removal efficiency of nitrate. The results showed that nitrate was almost completely transformed to nitrite in the first 4 days of column operation. After 2 days of accumulation of nitrite, its concentration slowly decreased and the compound was detected less than 0.5 mg/L in 14 days. In the experiment, sulfate concentration in the effluent was the 70~90 mg-S/L and the pH was maintained around pH 7.5. When nitrate concentration of bank filtrate in the real field is considered, this sulfate concentration seems to be acceptable. At 17 cm from the bottom of the column, the effluent showed the highest nitrite concentration, and nitrate concentration decreased rapidly to the Point of 33 cm from the bottom. The results suggest that an appropriate thickness of permeable reactive barriers is about 30 cm.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.04a
• /
• pp.20-23
• /
• 2005

The objective of this study is to examine a stabilized efficiency of heavy metals including Cd, Cu, Pb and Zn using slaked lime. Tailings from the Janggun Pb-Zn mine, the second Yeonhwa Pb-Zn mine, the Jisi Au-Ag mine and the Sangdong W mine were sampled and measured heavy metal concentrations contents using AAS as various extraction methods. During 156 hours, column test were undertaken to evaluate the possibility of stabilization by slaked lime. The result shows that $Ca(OH)_2$ has a good efficiency in heavy metal stabilization, especially at the Jisi mine with stabilized efficiencies of 97%(Cd), 99%(Cu), 86%(Pb) and 99%(Zn), respectively.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.04a
• /
• pp.176-179
• /
• 2003

Fuel oxygenates, such as Methyl tertiary Butyl Ether (MTBE) is additive in gasoline used to reduce air pollution. Gasoline components and fuel additives can leak form underground storage tanks. MTBE is far more water soluble than gasoline hydrocarbons like BTEX then it travels at essentially the same velocity as groundwater. MTBE in drinking water causes taste and odor problems. Therefore, the purpose of the this study is to examine the ability of ground rubber to sorb MTBE form water. The study consisted of running both batch and column tests to determine the sorption capacity and the flow through utilization efficiency of ground rubber. The result of Column test indicate that ground tire rubber has on the 36% utilization rate. Finally, it is clear that ground rubber present an attractive and relatively inexpensive sorption medium for a MTBE. The Author thought that to determine the economic costs of ground rubber utilization, the cost to sorb a given mass of contaminant by ground rubber will have to be compared to currently accepted sorption media.

• YAKHAK HOEJI
• /
• v.33 no.3
• /
• pp.175-182
• /
• 1989

To find ${\alpha}-amylase$ inhibitors produced by microorganisms from soil, a strain which had a strong inhibitory activity against bacterial ${\alpha}-amylase$ was isolated from the soil sample collected in Korea. The morphological and physiological characteristics of this strain on several media and its utilization of carbon sources showed that it was one of Streptomyces species according to the International Streptomyces Project method. The amylase inhibitor of this strain was purified by active carbon adsorption, silicagel column chromatography, SP-Sephadex C-25 column chromatography, adsorption on Amberlite XAD-2. The inhibitor was oligosaccharide which was composed of glucose. The inhibitor had inhibitory activity against other amylase such as salivary ${\alpha}-amylase$, pancreatic ${\alpha}-amylase$, fungal ${\alpha}-amylase$ and gluco-amylase.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10b
• /
• pp.603-608
• /
• 1998

This study was performed to examine the effect of time dependent properties on RC columns in subway structures subjected to high filled soil layer. By using Program TCC which is a modified version of CPF for the present purpose, a typical column in subway structure was analyzed. Four different model equations for predicted time dependent concrete properties(ACI, CEB-FIP, Bazant & Panula and Korea Bridge Specification) was employed, and the results were compared. It was found that a relevant creep coefficient is recommended to be 1.0 for designing columns in subway structure, and the sol filling work would be performed at least 3 months later after the concrete casting in order to ensure durability by reducing the negative effect of concrete time dependent properties.

• Journal of Soil and Groundwater Environment
• /
• v.20 no.2
• /
• pp.32-40
• /
• 2015

Laboratory column experiments were conducted to evaluate the feasibility of injectable apatite method for the sequestration of Sr-90 in groundwater. The columns were tested to evaluate the rate of citrate biodegradation, the amounts of apatite formed, and the treatability of strontium by the sediment and apatite. The results showed the decreases in citrate, calcium, and phosphate concentrations and the increases in alkalinity and citrate degradation products (acetate and formate) in the columns, suggesting that the citrate degradation and formation of calcium phosphate are occurring. Although the calcium and phosphate were not completely consumed within the columns, some amounts of apatite were formed and it showed an ability to treat strontium in groundwater. This study provides a fundamental understanding of reaction mechanisms for the injectable apatite sequestration method for Sr-90 removal.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.331.2-331.2
• /
• 2002

Actinomycetes CS0707 has been isolated in soil sample from location in the Jeju province. Korea, and produces thermostable extracellular proteases. Actinomycetes CS0703 showed the highest protease activity at late exponential phase when grown in OSYM medium (oatmeal 2.0%, soybean meal 1 %, dried yeast 1 %, mannitol 1 %) at $48^{\circ}C$. Three forms of protease(Ta-1, TA-2 and Ta-3) were fractionated by Ultrogel AcA 54 column chromatography, and further purified through ammonium sulfate fractionation, ultramembrane filtration, and DEAE-sepharose CL-6B column chromatography. (omitted)