• 한국연소학회:학술대회논문집
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• 한국연소학회 2007년도 제34회 KOSCO SYMPOSIUM 논문집
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• pp.155-160
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• 2007

This study was conducted to find out the chlorine removal characteristics of waste plastic mixture by pyrolysis process with thermogravimetric analysis(TGA) and a lab-scale pyrolyzer. The material used as plastic wastes were PE (Poly-ethylene), PP (Poly-prophylene), and PVC (Poly Vinyl Chloride). Experimental procedure were composed of three steps; 1st step: TGA of PVC, PP and PE, 2nd step: chlorine removal rate of PVC in a lab-scale pyrolyzer, 3rd step: chlorine removal rate of PVC-PE and PVC-PP mixture in a pyrolyzer. Through the results of TGA, we can estimate the basic pyrolysis characteristics of each plastic, and then we can also derive the design parameters and operating conditions of the lab-scale pyrolyzer. The results can be used as primary data for designing a system to produce RPF (Refuse Plastic Fuel), a waste incinerator and a pyrolysis/gasification process.

• Membrane and Water Treatment
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• 제9권3호
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• pp.173-179
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• 2018

Microcystin-LR, one of algal toxins induced by the eutrophication of a reservoir, is known to be harmful to human by adversely affecting our liver and brain. Hypochlorous acid is very efficient to remove Microcystin-LR in a clear well. The previous researches showed that CT, pH and temperature affected removal rate in batch tests. It was noted that hydrodynamic properties of clear well could also influence its removal rate. A mathematical model was built using an axial dispersion reactor model and software was used to simulate the removal rate. The model consisted of the second order differential equations including dispersion, convection, Microcystin-LR reaction with chlorine. Kinetic constants were obtained through batch tests with chlorine. They were $0.430{\times}10^{-3}L/mg/sec$ and $0.143{\times}10^{-3}L/mg/sec$ for pH 7.0 and 8.1, respectively. The axial dispersion reactor model was shown to be useful for the numerical model through conservative tracer tests. The numerical model successfully estimated the removal rate of Microcyctin-LR in a clear well. Numerical simulations showed that a small dispersion number, low pH and long hydraulic retention time were critical for higher removal rate with same chlorine dosage. This model could be used to optimize the operation of a clear well during an eutrophication season.

• 상하수도학회지
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• 제7권2호
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• pp.24-33
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• 1993

The effects of chlorine dioxide on the oxidation of phenol and disinfection were studied in the various test water conditions. With the 0.3mg/l of chlorine dioxide dose, the spiked phenol(initial concentration: 0.1mg/l) was completely oxidized within 10 minute. The removal rate of phenol was much faster in distilled water than in ground water and filtered water. The applied dose of chlorine dioxide concentrations higher than 0.2mg/l was sufficiently enough for the complete oxidation of phenol. However, with 0.1mg/l of dose, chlorine dioxide can oxidize only 20% of the spiked phenol. The reactive substances present in test water may influence the chlorine dioxide demand in water. pH effect of oxidation rate was also investigated. Increasing the pH, the removal rate of phenol was found to be increased. The disinfection test of chlorine and chlorine dioxide were conducted and compared. The lethal effect for the both disinfectants are similarly powerful. The time for 99% inactivation of E. coli was obtained within 120 sec with the 0.2mg/l of each dose.

• 한국환경보건학회지
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• 제33권4호
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• pp.338-343
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• 2007

Chlorine inhibition on the denitrifing activity of activated sludge treating dairy wastewater was investigated in this study. Filamentous bulking was caused artificially by a sudden load of feed and monitored by measuring sludge volume index. In cases of the activated sludge and bulking sludge which were contacted with chlorine as $7.5\;mgCl_2/gVSS/day$ for bulking control, the decreases of specific denitrification of $32.2{\sim}40.4%\;and\;43.5{\sim}46.5%$ were shown in comparison to the control group which was not reacted with chlorine, respectively. In continuous operation, it was observed that the removal efficiency of total nitrogen was more susceptible to chlorine than the removal efficiency of total phosphorus.

• 분석과학
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• 제29권3호
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• pp.126-135
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• 2016

상수원으로 유출될 가능성이 높은 잔류의약물질 대상으로 정수처리공정의 단위 공정별 잔류의 약물질 제어 효율을 평가하였다. 응집 공정에서는 Sulfonamide계 항생제는 22.6~42.1 % 제거 되었으며, Naproxen 28.2 %, Acetaminophen 20 %가 제거되었다. Trimethoprim은 4.4 %, Erythromycin은 2.4 %로 낮은 제거율을 보여 주었으며, Aspirin은 전혀 제거되지 않았다. 염소처리와 응집 혼합 공정을 적용하였을 때, 염소 주입량이 증가할수록 제거율이 증가되었다. 염소주입농도 3 mg/L일 때 Sulfonamide계 항생제, Acetaminophen, Naproxen은 100 %, Trimethoprim은약 98%로높은제거효율을나타내었으며 Erythromycin은 약 55 %, Aspirin은 약 10 %로 낮은 제거율을 보여 주었다. 분말활성탄 흡착 공정을 적용하였을 때, 분말활성탄 주입 농도가 증가할수록 제거율이 증가되었다. Sulfonamide계 항생제의 경우 1 mg/L에서 약 18~50 % 제거율을 보였으며, 25 mg/L에서는 약 80 % 이상으로 제거율이 증가하였다. 정수처리 공정에서 잔류의약물질의 효율적인 처리를 위한 염소처리와 흡착, 응집 공정의 적정 주입농도를 평가한 결과 염소 3 mg/L, 분말활성탄 10 mg/L, 응집제 15 mg/L을 적용했을 때 약 90 % 이상이 제거되었다.

• 한국환경과학회지
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• 제25권7호
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• pp.905-916
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• 2016

The characteristics of phenol removal and $UV_{254}$ matters variance were investigated and compared by the variation of operating factors (NaCl concentration, air flow rate, initial phenol concentration) in electrochemical reaction (ER) and dielectric barrier discharge plasma reaction (DBDPR), respectively. The phenol removal rate was shown as $1^{st}$ order both in ER and DBDPR. Also, the absorbance of $UV_{254}$ matters which means aromatic intermediates was analyzed to investigate the complete phenol degradation process. In ER, the phenol degradation and aromatic intermediates production rates increased by the increase of NaCl concentration. However, in DBDPR, the variation of NaCl concentration had no effect on the degradation of phenol and $UV_{254}$ matters. Air flow rate had a little effect on the removal of phenol and the variation of $UV_{254}$ matters in ER. The phenol removal rate in ER was a little higher than that in DBDPR. The produced $H_2O_2$ and $O_3$ amounts in ER were 2 times and 10 times higher than those in DBDPR. The chlorine intermediates ($ClO_2$ and free chlorine) were produced in ER, however, they were not produced in DBDPR.

• 한국환경보건학회지
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• 제30권1호
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• pp.59-64
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• 2004

This study was carried out to investigate influencing factors of bisphenol A(BPA) removal characteristic in conventional water treatment systems to be connected with coagulation, sedimentation, filtration and disinfection. The result are summarized as follows; In BPA removal, optimal doses of PAC, alum, ferric chloride were 7.5 mg Al/L, 10.0 mg AI/L, 15.0 mg Fek. PAC was most effective coagulant to remove BPA. In coagulation process, BPA removal efficiency were increased about 2％ by adjusting pH of raw water as 6. At temperature rise 1$0^{\circ}C$, BPA removal efficiency were increased 0.94％. but BPA removal efficiency in sand filtration process were under 1 ％ie, so that BPA was almost not removed. At free chlorine dose 1, 2 mg/L, the reaction rate constant k in the BPA removal have been calculated to be 0.397, 0.953 min$^{-1}$ . At free chlorine dose 1, 2 mg/1-, degradation reaction of BPA was completed during 10 min and BFA removal efficiencies were 97.66, 99.99％ at this time.

• 한국식품영양과학회지
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• 제38권5호
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• pp.601-604
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• 2009

본 연구는 이산화염소수 처리가 식품에서의 잔류농약 제거에 효과가 있는지 조사하기 위해서 수행되었다. 10, 50, 100 ppm 이산화염소수로 채소류에 흔히 쓰이는 농약인chlrpyrifos, diazinon, metalaxyl을 처리하여 GC를 이용하여 농약의 분해율을 측정하였다. 상기 세 가지 농약 성분은 이산화염소수 처리 농도뿐만 아니라 처리시간에 비례하여 분해되었으며 특히 100 ppm 이산화염소수 처리가 가장 효과적이었다. 또한, 인위적으로 농약을 오염시킨 상추를 증류수, 100 ppm 이산화염소수에 각각 침지하여 농약의 제거율을 비교해 보았을 때, 100 ppm 이산화염소수에 10분 동안 침지하였을 때가 가장 효과가 좋았다. 본 연구 결과, 이산화염소수 처리는 신선농산물에서의 잔류농약을 제거하기 위한 세척수로 이용될 수 있을 것으로 판단된다.

• 한국환경보건학회지
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• 제32권1호
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• pp.96-101
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• 2006

Chlorination inhibition on the organic removal activity of activated sludge microorganism was investigated in this study. It is well known that chlorination improves the settleability of filamentous bulking sludge through the selective impediment of filamentous microorganisms. However, it is based on the declination of effluent water quality after actual chlorination in dairy wastewater treatment plant. In case of the activated sludge which was exposed in the suggested concentration of chlorine $7.5\;mgCl_2/gVSS/day$ for the filamentous bulking control, decrease of organic uptake rate of $4.9\~24.0\%$, and dentrification rate of $24.8\~30.3\%$ ware shown in comparison to the control group which was not reacted with chlorine. As a result of comparing floc size of activated sludge microorganism, the average of floc diameter in the chlorine exposed group was $150\;{\mu}m$, which displays $25\%$ decrease compared with the control group.

• 상하수도학회지
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• 제9권4호
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• pp.107-114
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• 1995

The raw drinking water quality is getting worse because of the winter drought and the conventional treatment system is'nt suitable to obtain the satisfied quality of water. So, the advanced water system, BAC(Biological Activated Carbon) process is said to be effective to remove dissolved organics and ammonia nitrogen. In our study, the BAC pilot plant using Nak-dong river water is tested in low temperature. Following results are found from the study. The ammonia nitrogen removal rate of BAC system using wood-based carbon (PICABIOL) was 99% in $6^{\circ}C$ temperature. Chlorine dosage in wood-based BAC effluent was reduced to 67% of that in sand filtered wate. It resulted from the removal of ammonia nitrogen. Also, THM formed by chlorine addition in wood-based BAC effluent was decreased to 65% of that in sand filtered water. In the case of dual-filter, the removal efficiency of ammonia nitrogen was increased 30% more than in conventional sand filter. According to this result, the ammonia nitrogen load to BAC system could be lessened by the use of dual-filter.