• 한국환경과학회지
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• 제21권12호
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• pp.1523-1528
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• 2012

This study was carried out to develop pilot plant Net3FM(Net Fit Fiber Filter Module) system and to suggest optimum operating condition for municipal wastewater reuse. SS concentration of biologically treated sewage effluent was reduced from 1.5~5.4mg/L to 0.4~1.0mg/L without coagulant injection in Net3FM system, and the SS removal efficiency was average 84.7%. And also, the removal efficiencies of COD and T-P were decreased slightly due to the SS removal by filtration. Coagulation-Filtration test was conducted to enhance the removal efficiencies of SS and T-P. The optimum dosage of coagulant was injected automatically by auto-controlling system, which is controlled by detecting value of turbidity of secondary sewage effluent. SS, COD and T-P concentrations in filtrated effluent were 0.21~0.57, 1.6~6.2 and 0.137~0.392mg/L with coagulant injection by in-line mixer in Net3FM system, respectively. The removal efficiencies of SS and T-P were highly increased to 92.8% and 89.8%, respectively. It was due to the combined the processes of coagulation and filtration. Net3FM system was evaluated that the removal efficiency of pollutants in secondary sewage effluent and the utilization potential as reclaimed water technology were very high.

• 대한안전경영과학회지
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• 제13권2호
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• pp.259-266
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• 2011

Project owner, asbestos removal specialist, experts on asbestos removal work, as counter parts to be defined in the study to make out research goals have been asked with questionnaire survey and replied with 65, 275, 32 cases, respectively. And additionally, direct interview 73 sheets have been collected to find out current status of required engineers and equipments assigned and provided to the field, from them, three(3) concerned parties. Questionnaire subjects are composed of common items, reasonable unit cost, need of separate contract-awarding system, status of performing standard contract, status of providing legal engineers and equipments. Concentrated review of two~three questions by subject has been made to find out and compare idea results between three(3) concerned parties. First, legal and practical work status survey have been made to determine reasonability of introducing separate contract-awarding system, as a part of ensuring reasonable unit work cost. And then, two different status have been compared and there is introduction possibility of separate contract-awarding system, it is found out. The possibility of separate contract also has been confirmed by comparison of domestic legal grounds. Justificating grounds to introduce separate contract-awarding system have been shown. Standard contract status between asbestos removal specialists has been compared using two cases of providing removal work contract and receiving it. It is shown that case of 50 percent or less contains 38.5% when they receive contract, but only 10 percent reduction of original contract amount has been made when they provide it. It means that asbestos removal specialists do not keep occupational safety and health regulations.

• 에너지공학
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• 제10권4호
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• pp.342-348
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• 2001

A new design concept for a decay heat removal system in a liquid metal reactor is proposed. The new design utilizes a thermosyphon to enhance the heat removal capacity and its heat transfer characteristics are analyzed against the current PSDRS (Passive Safety Decay heat Removal System) in the KAL IMER (Korea Advanced LIquid MEtal Reactor) design. The preliminary analysis results show that the new design with a thermosyphon yields substantial increase of 20∼40% in the decay heat removal capacity compared to the current design that do not have the thermosyphon. The new design reduces the temperature rise in the cooling air of the system and helps the surrounding structure in maintaining its mechanical integrity for long term operation at an accident. Also the analysis revealed the characteristics of the interactions among various heat transfer modes in the new design.

• 환경위생공학
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• 제10권2호
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• pp.23-29
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• 1995

In this research effect of SRT, feeding pattern and reactor configuration on intermittently aerated activated sludge system was evaluated by using computer simulation model. T- N removal was affected to the SRT. SRT for the effective T- N removal was 156ay or longer. Feeding pattern in intermittently aerated activated sludge system was affect to the T- N removal. Feeding pattern which 100% loading to the first reactor was most effective for T- N removal. When multi- stage of 2- stage or more was operated, COD and T- N in effluent removal was nearly the same.

• 환경위생공학
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• 제12권2호
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• pp.65-74
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• 1997

The purpose of this study was to investigate the removal effect and variation of contaminated water by various water treatment processes using sediment filter, activated carbon, photocatalysis, reverse osmosis, ultra violet sterilizer and ultra filtration. The removal effect of chloride and trace metal was low by activated carbon and ultra filter but high in reverse osmosis. The removal effect of bacteria and E. coli was low by activated carbon and membrane filter system using activated carbon but high in impregnated activated carbon. The removal effect of TCE was low in sand and ultra filter system as compared with activated carbon. Ultra filtration process was effective for purify agricultural water without E.coli. Reverse osmosis was effective to remove heavy metal and activated carbon was effective to remove halogenated organic chemical compound. The flux and the removal effect of COD in spiral wound ultrafilter were higher than the hollow fiber ultrafilter.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.803-807
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• 2010

Schorl modified by $H_2SO_4$ has been successfully developed to enhance schorl-catalyzed Fenton-like reaction for removal of phenol in an aqueous solution. The phenol removal percentage can be increased from 4% to 100% by the system of modified schorl and $H_2O_2$. Batch experiments indicate that the percent increases in removal of phenol by increasing the dosage of catalyst, temperature and initial concentration of $H_2O_2$. The results of XRD, FT-IR and SEM suggest that no new phases are formed after removal of phenol by modified schorl. ICP-AES results reveal that more dissolution of iron results in higher catalytic oxidant activity in the system of modified schorl and $H_2O_2$. Besides minor adsorption, mineral-catalyzed Fenton-like reaction governs the process.

• 한국지반환경공학회 논문집
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• 제11권6호
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• pp.31-37
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• 2010

본 연구에서는 multi-bed 플레이트로 폐열재생 부분과 촉매반응 부분으로 구성되어 있는 복합열산화 시스템(Hybrid Thermal Oxidation System)을 이용하여 저온에서 주입 밸브 교체 시간간격과 유입유량을 변화시켜 VOCs(MEK와 Toluene) 제거를 평가하고자 하였다. $350^{\circ}C$의 연소온도 조건에서 VOCs는 완전히 전환되었으며 당량비에 따른 전환율 또한 100%에 근접하였고, HTO 시스템의 연소실은 좌우측의 온도가 균형을 이루며 열효율이 매우 높아 폐열회수 및 재생이 효율적이었다. 주입 밸브 교체 시간간격과 유입 유량 변화에 따른 HTO시스템에서의 VOCs 제거 효율은, MEK와 Toluene 모두 안정적으로 높은 91.1~97.4%의 효율을 나타내었으며, 보조연료량 증가보다는 밸브교대시간을 길게 하였을때 제거 효율이 증가하는 경향을 보여 보조연료량 증가보다 밸브교대시간을 증가시키는 것이 제거 효율을 높이는데 효율적으로 판단된다. 이와 같은 연구결과를 고려할 때 HTO시스템은 저농에서도 VOCs 제거, 특히 MEK과 Toluene 제거에 매우 안정적이며 콤팩트한 시스템으로 판단되며, 적은 설치 부지로 중소기업이 요구하는 새로운 VOCs 제거 시스템으로 적용 가능하리라 판단된다.

• 한국농공학회논문집
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• 제51권6호
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• pp.91-96
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• 2009

This study describes a zero discharge and reuse system developed for rural areas. The purpose of the system is decontamination of used irrigation water for down-stream usage and reuse of wastewater in rural villages for preventing water shortage problem expected to happen in near future. The system consists of anoxic, FES (Ferrous Electricity System), Oxic, Cralifier processes. The main feature of the system is to remove phosphorous by using Fe-ionizing module. Indoor experiments were undertaken with a trial product of the system to test its performance. The removal capacities of T-P, T-N, and BOD were examined. Also the proper time for the replacement of iron plate module was tested as well as the efficiency of T-P removal rate based on the usage of an automatic washing system for the iron plate. As results, the system showed very good water purification performances through obtaining the results of over 90% removal rates from T-P, BOD, and 67% from T-N. The proper time period for replacement of iron plate was maximum 2 years, and also efficiency of T-P removal rate found to be greatly influenced by the usage of an automatic washing system from the test.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2007년도 춘계학술발표논문집
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• pp.112-115
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• 2007

Currently an increase in domestic sewage and industrial wastewater causes serious water pollution in Korea. To solve water pollution problems, conventional activated sludge (CAS) system is generally used in wastewater treatment plant but this process is so ineffective in nitrogen and phosphorus. Even if CAS system is the major process, it must be improved instantly so as to remove nitrogen and phosphorus. Otherwise, the serious water pollution problems can't be resolved with CAS system. Therefore this study focused on the comparison of the treatment characteristics between ASA system and CAS system. And also the mass balance of each process of ASA system. The results from operating advanced step aeration (ASA) system indicated that the removal efficiency of BOD, COD, and SS was 89.9%, 74.5%, and 89.0% respectively. In comparison, the removal efficiency of BOD, COD, and SS for CAS system was 89.5%, 71.8%, and 89.5% respectively. In addition to the results, the TN removal efficiency of ASA system was 76.5% comparing to 32.7% of CAS system. It was concluded that the TN removal efficiency of ASA system was 44% higher than CAS system. And the TP removal efficiency was 81.4% in ASA system comparing to 25.2% in CAS system. It also means that over 56% of TP was removed in ASA system comparing to CAS system.

• 상하수도학회지
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• 제26권2호
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• pp.219-228
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• 2012

Problems due to the taste and odor in drinking water are common in treatment facilities around the world. Taste and odor are perceived by the public as the primary indicators of the safely and acceptability of drinking water, and are mainly caused by the presence of two semi-volatile compounds-2-methylisoborneol(2-MIB) and geosmin. Conventional treatment processes in water treatment plants, such as coagulation, sedimentation and chlorination have been found to be ineffective for the removal of 2-MIB and geosmin. Pulse UV system is a new UV irradiation system that is a non-mercury lamp-based alternative to currently used continuous wave systems for water disinfection. This study shows pulse UV system to be effective in treatment of these two compounds. Geosmin removal efficiency of UV process alone achieved approximately 70% at 10sec contact time. 2-MIB removal efficiency of UV only process achieved approximately 60% at 10sec contact time. The addition of $H_{2}O_{2}$ 7mg/L increased geosmin and 2-MIB removal efficiency upto approximately 94% and 91%, respectively.