• KSBB Journal
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• 제22권3호
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• pp.157-161
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• 2007

본 연구는 수계에서의 생물학적 고찰이 거의 없었던 MEA 단독 물질을 전형적 활성슬러지와 Pseudomonas계 균주를 이용하여 분해특성을 분석한 것이다. 잠정적 결론으로서 첫째, MEA는 수계 유입 시 COD 및 $NH_4^+$ 농도의 상당한 증가를 유발하여 MEA는 $NH_4^+$로 78.1% 이상 전환되었다. 둘째, 공기 공급이 조절된 회분식 반응기에서 MEA 분해속도는 1000 mg/L에서 최대 19.23 mg/L/h, 고농도인 5000 mg/L에서 17.55 mg/L/h로서 미생물 순응이 담보되는 경우 큰 차이를 보이지 않았다. 셋째, 순차적 순응단계를 거쳐 MLVSS가 상대적으로 작은 조건 (최대 820 mg/L)에서도 약 3개월간 안정적 장기 운전이 가능하였고, 최대 분해율은 약 95%였다. 넷째, $COD_{cr}$를 기초로 한 반응속도론 분석에 의하면 MEA 생분해는 1차 반응에 부합하였다. 향후 MEA의 생물학적 공법을 확립하기 위해 활성슬러지 시스템의 미생물 효소분석을 통해 순응단계를 최적화하는 연구를 수행할 계획이다.

• 한국물환경학회지
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• 제18권3호
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• pp.245-251
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• 2002

Reactive dyes waste water, a toxic and refractory pollutant, was treated by an electrochemical method using $Ti/IrO_2$ as anode and Stainless Steel 316 as cathode. In this technique, sodium chloride as an electrolyte was added. A number of experiments were run in a batch system. Artificial samples (reactive blue 19, red 195, yellow 145) were used. Operation parameters, such as supporting electrolyte concentration, current density, pH and sample concentration have been investigated for their influences on COD and color removal efficiencies during electrolysis. After 5 and 90 minites of eletrolysis, color was reduced by 51.5% and 98.9% respectively. Under the condition of current density $10A/dm^2$, NaCl concentration 12mg/l and pH 3, 62.9% of $COD_{Cr}$ was removed after electrolysis for 90 minites. The optimum condition of color removal and COD reduction in this work was found to be the following : pH 3, sodium chloride concentration 20g/l, current density $10A/dm^2$. As a result, we confirmed to be effective to color removal and reduction of refractory organic material.

• 대한기계학회논문집
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• 제8권2호
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• pp.97-103
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• 1984

본 연구에서는 이에 주목하고 잔존하는 잔유응력을 제거한 상태에서 PWHT가 용접 HAZ조직의 파괴인성에 어떠한 영향을 미치고 있느가와 잔유응력이 잔존된 상태에 서의 PWHT 유대시간과 가열속도가 파괴인성에 어떠한 영향을 미치는가를 알아보기 위 하여 공시재에 무응력과 일정응력을 가한 상태에서 유대시간과 가열속도를 변화시켜가 며 PWHT를 실족한 후 소성굽힘에 의한 COD파괴인성 시험 등을 통하여 PWHT의 영향을 검토하였다.

• 디지털융복합연구
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• 제12권8호
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• pp.283-288
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• 2014

석유 제품 지하 저장 공동의 지하수 수질은 공동 인근 매립지 수질의 영향을 받는다. 매립지 주변의 지하수 수질 분석 결과, 시료의 반 정도에서 지하공동 수질에 영향이 미미한 농도의 As, Cu 및 Pb가 검출되었으며, Cd, Hg, $Cr^{6+}$, $CN^-$, TCE, PCE 및 Pheno은 검출되지 않았다. $COD^{Mn}$의 농도는 모든 시료에서 $8.0mg/{\ell}$이하로 유기물질에 의한 지하수 오염은 거의 없는 것으로 분석되었다. 1차, 2차 미생물 분석결과 총박테리아는 각각 $94.84{\times}10^4cells/{\mu}g/m{\ell}$과 $146.26{\times}10^{-4}cells/{\mu}g/m{\ell}$이고 황산환원 박테리아는 $2cells/m{\ell}$이하로 분석되어 지하공동의 수질에 영향이 미미할 것으로 분석되었다. 저장 공동 인근 지역의 지하수 수질 분석은 공동의 수리 지질의 안정성을 향상시키기 위하여 지속적인 조사와 관리가 필요할 것으로 판단된다.

• 상하수도학회지
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• 제18권4호
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• pp.470-479
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• 2004

The experimental conditions and relationships between parameters such as organic matter, aeration volume, aeration time, and precipitation time for the effective treatment of domestic wastewater were investigated. With the batch systems, the adsorption amount of unit microbe was measured with the change of MLSS concentration, precipitation time, and aeration amount. Theoretical adsorption amount of microbes was then numerically formulated by use of a SPSS multiple analysis as follows: $$Y=-0.0106(X_1)+0.07310(X_2)+42.705(X_3)+62.700$$ In this study, the amount of organisms to be removed in the range of MLSS concentration 2,000~4,500 mg/l were examined. In order to investigate the optimal condition of nitrification, the upper water in the biosorption stage was used as the initial experiment water. The results showed that the C/N ratio was 1.5 and the reaction time for the optimal nitrification was 1.5 hr. When the adsorption efficiency for microbe biosorption was 66%, the optimum denitrification efficiency was 83.3%. When the optimum parameters obtained from the batch experiment were applied to the lab-scale operation, the total retention time from the flow-in to flow-out was 10 hours and the removal efficiency was 93.8% for $COD_{cr}$ and 80.9% for TN. For the full-scale operation, the total retention time was 9.0 hours and the removal efficiency was 94.4% for BOD, 89.6% for $COD_{cr}$, 88.0% for TN, and 86.2% for TP.

• 한국환경과학회지
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• 제24권12호
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• pp.1609-1616
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• 2015

The objective of this study was to make a SBR+MBR complex process to evaluate the possible use of the advanced water treatment system for ships (SBR+MBR complex process) in accordance with the amendments MAPOL 73/78 that went into effect. The conditions 1 and 2 did not show the quick reduction in anaerobic condition while in the precipitation and stirring stages of the SBR treatment which was determined to be ineffective denitrification, same as with the ORP. Removal of organic matters such as $BOD_5$ and $COD_{Cr}$ in the SBR treatment was observed to happen smoothly and going through the MBR treatment as well would provide a stable water quality. However, the results were not satisfactory in accordance with $BOD_5$ 25 mg/L and $COD_{Cr}$ 125 mg/L. Thus, the operating conditions improvement is deemed necessary. Likewise for the nutrients (T-N and T-P), the nitrification in bioreactor, denitrification and phosphorus absorption in aerobic tank due to phosphorus release in anaerobic tank had not been proceeded effectively. It was concluded that the improved operating conditions and structural changes would provide more effective treatments since the removal rates of T-N and T-P were less than 70% and 80%, respectively, which were standards specified by the MEPC. 227(64).

• 한국환경과학회지
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• 제15권3호
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• pp.193-201
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• 2006

Advanced oxidation processes involving $O_3/H_2O_2$ and $O_3/catalyst$ were used to compare the degradability and the effect of pH on the oxidation of 1,4-dioxane, Oxidation processes were carried out in a bubble column reactor under different pH. Initial hydrogen peroxide concentration was 3.52 mM in $O_3/H_2O_2$ process and 115 g/L (0.65 wt.%) of activated carbon impregnated with palladium was packed in $O_3/catalyst$ column. 1,4-dioxane concentration was reduced steadily with reaction time in $O_3/H_2O_2$ oxidation process, however, in case of $O_3/catalyst$ process, about $50{\sim}75%$ of 1,4-dioxane was degraded only in 5 minutes after reaction. Overall reaction efficiency of $O_3/catalyst$ was also higher than that of $O_3/H_2O_2$ process. TOC and $COD_{cr}$ were analyzed in order to examine the oxidation characteristics with $O_3/H_2O_2\;and\;O_3/catalyst$ process. The results of $COD_{cr}$ removal efficiency and ${\Delta}TOC/{\Delta}ThOC$ ratio in $O_3/catalyst$ process gave that this process could more proceed the oxidation reaction than $O_3/H_2O_2$ oxidation process. Therefore, it was considered that $O_3/catalyst$ advanced oxidation process could be used as a effective oxidation process for removing non-degradable toxic organic materials.

• 대한환경공학회지
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• 제27권11호
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• pp.1162-1167
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• 2005

축산폐수는 고농도의 난분해성 유기물질을 많이 함유하고 있기 때문에 처리하기가 매우 어려운 것으로 알려져 있다. 따라서 본 연구에서는 현장에 건설된 오존을 이용한 시스템인 DOF(Dissolved Ozone Flotation)와 PO2(Pressurized Ozone Oxidation)에 의한 축산폐수의 처리특성을 조사하였다. DOF-PO2의 유입수내에 존재하는 SS의 제거율은 94%를 상회하여 약 400 mg/L의 농도를 22 mg/L까지 낮출 수 있었다. $COD_{Mn}$의 제거율도 90%정도로 620 mg/L로 유입되어 63 mg/L로 유출되었다. $SCOD_{Cr}$은 890 mg/L 정도가 유입되었으며 82%가 제거되어 160 mg/L 정도로 유출되었다. UV-254흡광도는 96%제거 되었다. 특히 TP의 제거율은 98%가 넘었고 27 mg/L가 유입되어 0.35 mg/L만이 유출되었다. TN도 SS의 제거와 함께 68%정도 제거되었으나 오존에 의한 제거효과는 없었다. DOF-PO2시스템에 의한 고농도 오존산화공정을 미생물처리공정과 같이 적용할 경우 축산폐수처리공정의 방류수 수질기준을 맞출 수 있었다.

• Environmental Engineering Research
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• 제10권5호
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• pp.247-256
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• 2005

A combination of the submerged membrane activated-sludge bioreactor(SMABR) equipped with non-woven fabric filter and oyster-zeolite (OZ) packed-bed adsorption column was studied to evaluate the advanced tertiary treatment of nitrogen and phosphorous. The non-woven filter module was submerged in the MBR and aeration was operated intermittently for an optimal wastewater treatment performance. Artificial wastewater with $COD_{Cr}$ of 220 mg/L, total nitrogen (T-N) of 45 mg/L, and total phosphorous (T-P) of 6 mg/L was used in this study. MLSS was maintained about $4,000\;{\sim}\;5,000\;mg/L$ throughout the experiments. The experiments were performed for 100-day with periodic non-woven filter washing. The results showed that $COD_{Cr}$ could be effectively removed in SMABR alone with over 94% removal efficiency. However, T-N and T-P removal efficiency was slightly lower than expected with SMABR alone. The permeate from SMABR was then passed through the OZ column for tertiary nutrients removal. The final effluent analysis confirmed that nutrients could be additionally removed resulting in over 87% and 46% removal efficiencies for T-N and T-P, respectively. The results of this study suggest that the waste oyster-shell can be effectively reclaimed as an adsorbent in advanced tertiary wastewater treatment processes in combination with SMABR equipped with non-woven fabric filter.

• 한국환경보건학회지
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• 제31권1호
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• pp.15-22
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• 2005

This study was conducted to evaluate air injection mode on stabilization of solid waste in lysimeter. For three lysimeters, one was maintained under anaerobic condition as control, and air was injected into two lysimeters in continuous mode (atmospheric pressure) and intermittent mode (high pressure of 2 bar). Distilled water was sprayed over solid waste in 1.4 l/$m^3$(solid waste)/day, supposing rainfall intensity of 1,200 mm/yr and 30% infiltration. Oxygen in landfill gas was not detected in control lysimeter during operational days. After 30 day-aeration, oxygen concentrations of continuous and intermittent modes were maintained in 14% and 6%, respectively. $COD_{Cr}$ removal efficiencies of continuous and intermittent modes were about 70% and 50%, and BOD5 removal efficiencies were about 80% and 20%, respectively. In view of oxygen supply, and $COD_{Cr}$ and $BOD_5$ removal, continuous air injection mode of atmospheric pressure was more effective than intermittent mode of 2 bar. Settling degree of solid waste in case of two air injection modes was 3 times higher than that of anaerobic condition as control. Considering the above results, it was thought that air injection (especially continuous atmospheric pressure) could improve degradation of solid waste and induce preliminary stabilization in landfill site.