• Journal of Soil and Groundwater Environment
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• v.9 no.1
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• pp.87-94
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• 2004

The effects of pretreatment of GAC and dissolved oxygen (DO) on the sorption capacity for ο-cresol were investigated using pretreated GAC under oxic and anoxic conditions. Virgin GAC was used with pretreated GACs by $O_2$, acid and base as sorbents. Sorption capacity of GAC was dependent on the oxygen conditions according to the pretreatment methods. Virgin GAC showed increased sorption capacity when DO was present in the solution, while $O_2$-pretreated GAC did not show any considerable capacity change. Acid- and base-pretreated GACs were relatively more influenced by presence of DO as compared with virgin GAC. Both acid and base-pretreated GACs showed a rapid sorption rate at the initial stage, but as contact time became longer the sorption was slower. Sorbed ο-cresol was extracted with micro-Soxhlet extraction apparatus using the GAC separated from the rate experiments. Within 1 hour both acid and base-pretreated GACs showed the decrease in extraction efficiencies under both oxic and anoxic conditions. After 1 hour such a trend (the increase as contact time was longer) was not observed and showed relatively constant efficiencies of 35∼50%. According to the results of this study $O_2$contacted with GAC before sorption as well as DO present in the solution during sorption could influence the GAC sorption capacity.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.554-563
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• 2013

The purpose of this study is to evaluate the possibility of nutrient release at up and downstream of Kangchun weir, upstream of Yuju and Ipo weir in Namhan River. For this survey, we measured basic characteristics of the sediments (water content, ignition loss, TOC, TP, SRP, TN, phosphorus fractionation) and conducted nutrients release experiments under both aerobic and anaerobic condition. The overlying water from the sediment-water column was analyzed for nutrients (i.e. TP, $PO_4$-P, TN, $NO_3$-N, $NH_3$-N) everyday for 18days. Result of soil texture experiment showed that sediments are Sand. SRP concentration before the release experiment was different with the value after the release experiment. According to this result, we can find that there were more activated release processes in anaerobic condition. $PO_4$-P increased from 1 to 8 days and remained at the maximum value (7~8 days) afterward. The rapidly increase of $PO_4$-P was observed from 1 to 2~3 days whereas the TP continuously increase from 1 to 18 days. The $PO_4$-P release rate calculated by up to 7~8 days data highly correlated with initial SRP concentration with $R^2$=0.8502. $NO_3$-N release rate appears constantly decreasing trend as -5.7~-3.08 $mg/m^2{\cdot}day$, otherwise the $NH_3$-N release rate, by-product of a organic matter decomposition using nitrate as electron acceptor, was 0.57~2.41 $mg/m^2{\cdot}day$. Substantial portion in TN can be induced by organic nitrogen which originated from the tributary passing through non-point pollutant source. Compared with other similar researches, phosphorus and nitrogen release rates obtained in this study can be considered as relatively low values. Since this study targeted the sediments accumulated by one time of flooding season, there are limitation to generalize theses results. Therefore, it is necessary to consistently monitor and investigate the accumulation of nutrients in the sediment for understanding the effect of weir construction on the overlying water quality.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.75-84
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• 2005

The aim of this study is to evaluate the leaching characteristics of lead, copper, cadmium, and mercury from steel making slag by seawater. To demonstrate the leaching characteristics of heavy metals from steel making slag by seawater, it was carried to various leaching tests such as regular leaching tests, liquid/sold(LS) leaching test and pH static test. From the leachability of $Pb^{+2},\;Cu^{+2},\;and\;Cd^{+2}$ from steel making slag in pH static test, it is distinguished between distilled water and seawater. With distilled water, it is very low between pH 7-8 and pH 11-12. On the other hands, with the seawater, its leaching is higher than that of distilled water. In particular, concentration of $Hg^{+2}$ leached from slag by seawater is lower than that of distilled water. Meanwhile, we found that the heavy metals from steel making slag would be dissolved and precipitated using geochemcial equilibrium program such as visual minteq. Lead and copper leached from steel making slag with seawater were dissolved nearly in the range of pH 11-12, but in the range of pH 7-10 those were precipitated about 90%. And cadmium leached from steel making slag with seawater were dissolved completely. On pH static test with distilled water, lead leached from steel making slag seemed to be similar to pH static test with seawater. However, copper and cadmium leached from steel making slag were dissolved. In general, the species of lead leached from steel making slag were formed mainly of $PbCl^+,\;PbSO_4$, the species of copper were formed mainly of $CuSO_4,\;CuCO_3$, the species of cadmium were formed mainly of $CdCl^+,\;CdSO_4$ due to being sorbed with the anions($Cl^-,\;CO_3^{-2},\;SO_4^{-2}$) of the seawater. Both pH static test with seawater and distilled water, it is not in the case of the mercury. Most of mercury leached from steel making slag was precipitated(SI=0). Because the decreasing of $Hg^{+2}$ concentrations depends ferociously on the variation of chloride($Cl^-$) existed in the seawater. $Hg^{+2}$ leached from steel making slag could be sorbed strongly with chloride($Cl^-$) compared of carbonate($CO_3^{-2}$) and sulfate($SO_4^{-2}$) in the seawater. On the basis of that result, we found that the species of mercury was formed of calomel($Hg_2Cl_2$) as one of finite solid. Due to forming a calomel($Hg_2Cl_2$) in the seawater, the stability of mercury species by steel making slag should be higher than those of lead, copper, and cadmium species. Regarding the results stated above, we postulated that the steel making slag could be recycled to sea aggregates due to being distinguishing leachability of heavy metals($Pb^{+2},\;Cu^{+2},\;Cd^{+2},\;and\;Hg^{+2}$) between leaching tests by distilled water and seawater.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.304-310
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• 2003

This study was conducted to estimate the internal dissolved organic carbon (DOC) loading from sediment in eutrophic shallow Lake Kasumigaura. Contents of water and organic carbon were about 80% and 6.3% with depth in the sediment, respectively. The highest DOC concentration in porewater (104 mg C/l) was observed in September suggesting that the porewater could play an important role as an internal loading of DOC. Results of DOC release experiments showed that the labile-DOC (L-DOC) release was not detected in the oxic condition, while refractory-DOC(R-DOC) release was detected. The L-DOC and R-DOC release rates in the anoxic codition ranged from 14.5${\sim}$ 48.6, 14.4 ${\sim}$27.3 mgC $m^{-2}$ $d^{-2}$, respectively. The current study showed that L-DOC released in the oxic condition was rapidly utilized by aerobic bacteria, in contrast, L-DOC and R-DOC released in anoxic codition were slowly utilized by anaerobic bacteria. These results suggested that L-DOC and R-DOC were closely related to sediment release and most of the R-DOC released could be an important source of DOC in eutrophic lakes during summer. Therefore, R-DOC pool should be added as one of the important energy source for microbial-based aquatic food webs in eutrophic lakes.

• Korean Journal of Food Science and Technology
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• v.19 no.6
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• pp.492-498
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• 1987

Dried soybeans (varieties: Saeal, Kwanggyo, Tanyob) took up water rapidly for first 3hr followed by a slower rate of uptake. The beans took up an equal weight of water (100% hydration)after approximately 3.5hr at $50^{\circ}C$, 5hr at $30^{\circ}C$ and 7.5hr at $20^{\circ}C$ respectively. pH of the soaking solutions decreased during the soaking period. This was undoubtedly caused by the ionization of the cellular components resulting in increased levels of hydrogen ions in the liquor. Soluble solids were leached out of the beans at fairly steady rate throughout the hydration and the amount was greater with higher temperature. This amounted to 0.4-0.7g at $20^{\circ}C$ and 10.2-15.0g at $50^{\circ}C$ per 100g soybeans. Temperature was the most important factor in determining the rate of water absorption and of solid losses. Of the total solids lost, 12-25% was protein. The proportion of protein loss increased as the soaking time and temperature increase. Amount of protein loss was 80-200mg at $20^{\circ}C$ and 440-480mg at $50^{\circ}C$ after 24hr soaking per 100g soybeans. About 5% of soluble sugars, including fructose, sucrose, raffinose, and stachyose, was removed from the beans after 24hr soaking at $20^{\circ}C$.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.572-574
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• 2003

현대사회의 소비자는 극도의 편리성을 추구하는 경향이 있다. 식품업계에서는 이를 충족시키기 위하여 다양한 형태의 인스턴트 식품을 개발하고 있으며, 이에 따라 식품의 포장용기도 매우 다양해지고, 일회용 식품포장용기의 사용도 급증하고 있다. 일회용 식품포장용기는 그 재질에 따라서 유해물질이 용출되거나 갖가지 형태로 소비자의 건강을 위협하고 있다.(중략)

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.361-367
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• 2010

The use of antifouling(AF) paints is the effective method for the protection of underwater structures from the development of marine fouling organisms. The ban on harmful substances in antifouling paints requires the development of new antifouling strategies although Tributyitin (TBT) compound had been used extensively as an active ingredient Alternatives should be as effective as conventional paints but have lower toxicity. In the present study, a TBT-free self-polishing (Cu SPC) AF paint containing $Cu_2O$, a Cu free SPC AF paint, and a Foul-release silicone AF paint, which were commercially available, were examined to investigate environmental erects of leakage waters employing Sebastes shlegeli and Artemia. Survival rates were inversely proportional to the concentration of leakage waters from AF paints and the acute toxicity of SPC AF paints was relatively higher than that of foul release AF paints.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.05a
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• pp.227-231
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• 2003

제주항을 대상으로 오염부하의 정량적인 관리를 위하여 물질순환모델을 이용하여 해수유동특성과 COD, DIN 그리고 DIP의 농도분포를 시뮬레이션 하였고, 이 결과를 통해 해역의 수질개선대책으로 하천오염부하 감소와 저질개선을 통한 용출부하 감소에 따른 COD, DIN 그리고 DIP의 농도를 정량적으로 평가한 결과는 다음과 같다. 외부부하인 하천유입 부하량의 감소에 의한 제주항 내 오염물질 농도의 저감효과는 만 중앙부에서 만 외로 갈수록 그 영향범위가 미비하나 하천 유입부에 한정되어 큰 효과를 나타내고 있어 제주항 내로 오염부하의 유입을 방지함으로서 제주항의 하천 유입부 수질개선에 큰 영향을 줄 수 있다. 내부부하인 저질 영양염 용출부하를 감소했을 경우의 제주항 내 영영염 농도의 저감 효과는 하천유입 부하량의 저감시와 상대적으로 비교하여 제주항의 하천 유입부보다는 만 중앙부나 만 유입부의 수질개선에 효율적인 영향을 보이는 것으로 사료되며 특히, DIP의 경우 그 양상이 잘 나타났다. 하천과 저질의 총 부하량을 100% 감소했을 경우, COD의 농도분포는 하천유입부인 정점 St. 1에서 약 44%정도의 저감효과를 나타내어 하천유입 부하량만을 감소했을 때보다는 저감효과가 증가하였다. DIN의 경우는 하천유입부하와 저질 용출부하를 각각 따로 저감했을 경우에 비해 전체적으로 저감효율이 상승하고 있으며, 만 중앙부에서 만 유입부로 갈수록 그 경향이 잘 나타나고 있으며 총 부하를 저감시켰을 때 제주항내의 DIN 농도는 정점 St. 3 다음 지점부터 해역수질기준 II등급을 유지되는 수질개선 효과를 나타내었다. DIP의 경우는 DIN과 유사한 경향을 보였으며 정점 St. 4 이후로 해역수질기준 II등급 이하로 유지되는 수질개선 효과를 나타내었다. 이상의 결과로 볼 때, 현재 해역수질기준 III등급인 제주항 내에서 수질을 향상시키기 위해서는 하천유입부하량의 저감뿐만 아니라 항내 저질개선 등을 통하면 전체적으로 II등급 이하를 유지할 수 있을 것으로 예상된다.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.49-53
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• 1996

Acid-modified starch was prepared by treating a warm aqueous starch suspension with dilute mineral acid$(0.2\;N\;HCl,\;45^{\circ}C,\;20\;mim{\sim}1\;h)$. The swelling power and solubility of acid-modified red bean starches increased and the changes occurred at tower temperature. According to gel chromatography of starches, the amylose and amylopectin moieties of red bean starches were not affected very much by hydrolysis conditions used. The elution profiles of soluble carbohydrate showed that the larger molecules were leached as the heating temperature increased. Total amounts of soluble carbohydrate were increased by acid-modification. The gel strength of acid-modified starches at each temperature increased, whereas cohesiveness decreased in acid-modified starch gels except at $85^{\circ}C$.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.182-185
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• 2005

울산광산 내 지표수와 토양 중의 공극수에 함유되어 있는 비소의 오염현황을 파악하고, pH와 산화-환원 전위 값의 변화에 따른 자연저감 능력을 평가하였다. 유비철석을 비롯한 비소함유 광물은 높은 산화-환원 전위 값과 낮은 pH 조건에서 해리되며, 이후 지하수의 진화과정에서 pH가 상승함에 따라 주로 5가의 비소형태로 존재하게 된다. 울산광산지역 지하수의 비소농도는 Eh가 높은 비포화대와 포화대 지하수의 경계부에서 높은 경향을 나타내며, 포화대의 상부에서는 Eh가 비교적 일정하나 비소 농도는 다양한 분포양상을 보인다. 포화대 하부에서 비소의 함량은 매우 낮으며, Eh 감소에 따라 비소 함량이 비례적으로 감소한다. 반응경로 과정에서 비소농도는 Eh<-0.1(V)인 지하수 포화대에서 가장 낮으며, pH가 상대적으로 낮고 산화-환원 전위값이 높은 비포화대에서 증가되는 경향을 보인다. 풍화 반응 정도가 높은 광미와 토양에서 비소농도 높으나, 용출실험에서 비소가 기준치 이하로 용출되는 것은 풍화반응과 토양에 의한 비소의 자연저감이 진행되고 있음을 반영한다. RMB를 이용한 중금속 제거능력 평가 실내실험에서, 산성과 알칼리 조건 모두에서 제거율이 높은 것으로 나타났다. 인회석과 철산화물질로 구성된 RMB는 친환경적이고 2차 오염문제를 극복할 수 있는 물질로서, 비소의 자연저감 능력을 향상시킬 수 있는 정화처리제로 활용이 가능할 것으로 판단된다.