In this study, a two-stage electrostatic precipitator (ESP) was developed using a novel automatic dry cleaning device to reduce the ultrafine particles in subway stations. Collection efficiency was evaluated with a pilot scale ESP (1.2m× 1.2m) and the scale of the test duct was half of the subway air handling unit. The maximum collection efficiency for 0.3 μm particles was 96.9%. In addition, we studied a method of automatic dry cleaning for maintenance of the ESP. The cleaning efficiency was analyzed according to the cleaning flow rate for each particle loading amount to achieve a recovery rate over 90%. In addition, we derived the equation to estimate the reduction in collection efficiency according to the particle loading amount. It was confirmed that the performance of the contaminated ESP was restored to the initial state by the automatic dry cleaning in this study and that the electrical energy consumption was 5 times lower compared to utilizing conventional water cleaning.

A porous photocatalyst concrete filter was successfully produced to remove NOx, by mixing TiO2 photocatalyst with lightweight aerated concrete. Ultra Fine Bubbles were used to form continuous pores inside the porous photocatalytic concrete filter, which was mixed via a bubble generation experiment. The optimal mixing condition was determined to be with 4% of the bubble generation agent B. NO removal specimens were prepared for various photocatalytic loading conditions, and the specimen containing 3% P-25 removed NO at a concentration of 1.03 μmol in 1 h. The NO removal rate of the porous photocatalytic concrete filter prepared in this study was 10.99%. This photocatalytic filter performance was more than 9 times the amount of NO removed by a general photocatalytic filter. The porous photocatalyst concrete filter for removing NOx developed in this study can be applied to various construction sites and the air quality can be solved by reducing NOx contributing to the formation of fine particles.

This experiment evaluated the efficiency of mechanical ventilation, one of the measures to reduce indoor radon concentration in residential spaces. In the most popular ventilation rates of the air conditioning system, the most efficient air conditioning system was confirmed by checking the time when the radon concentration reached the lowest level, the radon reduction rate, and the radon concentration that could be lowered as much as possible. The results showed a reduction rate of up to 80% or more as a result of conducting the experiment by blocking the inflow of outside air. It was confirmed that the time to reach the lowest concentration after starting the mechanical ventilation was about 6 hours to a maximum of 7 hours. Therefore, this study verified that indoor radon concentrations can be efficiently reduced by using a mechanical ventilation system.

PURPOSES : NOx is a particle matter precursor that is harmful to humans. Various methods of removing NOx from the air have been developed. TiO2 and activated carbon are particularly useful materials for removing NOx, and the method is known as particulate matter precursor reduction. The removal of NOx using TiO2 requires sunlight for the photocatalytic reaction, whereas activated carbon absorbs NOx particles into its pores after contact with the atmosphere. The purpose of this study is to evaluate the NOx removal efficiency of TiO2 and activated carbon applied to concrete surfaces using the penetration method. METHODS : Surface penetration agents, such as silane-siloxane and silicate, were used. Photocatalyst TiO2 and adsorbent activated carbons were selected as the materials for NOx removal. TiO2 used in this study was formed by crystal structures of anatase and rutile, and plant-type and coal-type materials were used for the activated carbon. Each surface penetration agent was mixed with each particulate matter sealer at a concentration ratio of 8:2, and the mixtures were sprayed onto the surface. The NOx removal efficiency was evaluated using NOx removal efficiency equipment fabricated in compliance with the ISO 22197-1 standard. RESULTS : Anatase TiO2 showed a maximum NOx removal efficiency of 48% when 500 g/m² was applied. However, 500 g/m² of rutile TiO2 showed a NOx removal efficiency of up to 10%. When 700 g/m² of coal-based activated carbon and plant-based activated carbon was used, NOx removal efficiencies of up to 11% and 14%, respectively, were obtained. CONCLUSIONS : Rutile TiO2, a coal-based activated carbon, and plant-based activated carbon have lower NOx removal efficiencies than anatase TiO2. A lower amount of anatase TiO2 (500 g/m²), compared to the other spraying volumes, yielded the most significant NOx removal efficiency under optimal conditions. Therefore, it is recommended that 500 g/m² of anatase TiO2 should be sprayed onto concrete structures to improve the economic and long-term performance of these structures.

High concentrations of PM2.5 were generated in new apartments before moving in, and PM2.5 reduction efficiencies using air cleaners and ventilation systems were evaluated. The experimental results for different air cleaner capacities showed that the PM2.5 reduction efficiencies for 46.2 m2, 66 m2, and 105.6 m2 areas were 81.7%, 92.9%, and 92.5%, respectively. Thus, the larger the air cleaning application area, the higher the PM2.5 reduction efficiency. However, there was no difference in the efficiency of overcapacity air cleaners above a certain capacity. The efficiencies of air cleaners located at the living room center, interior wall, and edge were 81.7%, 79.2%, and 75.8%, respectively. There was, therefore, no significant difference in the PM2.5 reduction efficiencies of air cleaners in different locations. Furthermore, the PM2.5 reduction efficiencies at distances of 1 m, 2 m, and 3 m were 81.7%, 81.3%, and 81.7%, respectively. Therefore, there was also no significant difference in efficiency with distance. The PM2.5 concentration decreases rapidly during natural ventilation. Therefore, when the indoor PM2.5 is higher than the outdoor PM2.5, the air cleaner should be used after natural ventilation. The efficiency of PM2.5 reduction using an air supply-type ventilation system in apartments was 35%, which is not high. The simultaneous operation of the ventilation system and kitchen range hood was effective, showing a PM2.5 reduction efficiency of 69.1%. However, a water sprayer was not effective, showing a PM2.5 reduction efficiency of 24.3%. The results of this study suggest that PM2.5 reduction performance should be standardized by evaluating the efficiency of different ventilation systems. Effective usage and maintenance standards for ventilation systems need to be disseminated, and ventilation systems and air cleaners should be used effectively.

본 연구는 L-alanine을 적용한 스크러버의 주류공장 내 CO2 제거효율, 모니터링 데이터 분석/ 평가 및 에너지 저감효율을 평가하였다. 스크러버의 평균 제거율은 90.45%로 10,000 ppm이상의 고농도 CO2가 유입됨에도 제거효율이 뛰어난 것을 확인하였다. 스크러버 작동 후 작업장 내 CO2는 2,000ppm 이 하로 유지하여 약 74% 이상의 이산화탄소 저감 효율을 확인하였다. 또한 소비되는 전력량을 측정한 결과 스크러버 작동 후 230 kWh로 약 7.26%의 에너지가 절감되는 것으로 나타났다. 즉, 본 개발제품을 적용한 결과로 작업장 내 이산화탄소 농도를 외기유입 없이 낮은 농도로 유지함에 따라 근무자의 작업환경을 개선 시킬 수 있었으며 에너지 소비량 또한 저감할 수 있었다. 그러므로 식품, 주류공장 내 고농도 CO2 제거 공 정으로써 스크러버가 유용할 것으로 기대된다.

The odor substances generated in a feed manufactory operating for the commercialization of animal-vegetable materials were analyzed and the odor reduction efficiency by a chemical scrubber was evaluated. The major causative substances in the feed manufactory comprised about 45.4% of ketone compounds and about 13.3% of aldehyde compounds. On the other hand, the removal efficiencies of diacetyl and acetoin as ketone compounds were 77.3% and 78.1%, respectively, by a chemical scrubber. Additionally, the removal efficiencies of acetaldehyde, butyraldehyde, valeraldehyde, 2-furancarboxaldehyde, and nonanal were 86.0%, 78.9%, 67.4%, 52.8%, and 71.9%, respectively. These rates were higher than the odor generation substance contribution rate as a result of treating the exhaust gas generated from the feed manufactory by the chemical scrubber using 5% of C3. It was also found that xylene, methylcyclopentane, benzene, ethylbenzene, 1,3,5-trimethylbenzene, and decane were almost not removed.

폐 RHDM(Residue Hydrodemetallation) 촉매상에 침적된 비활성화 성분인 탄소, 황 을 고온배소 처리하여 제거한 후, 과량 침적되어 있는 바나듐은 초음파 교반기에서 5~15wt% 옥살산 수용액을 이용하여 50℃, 5분 조건하에 바나듐 추출량을 조절함으로써 NOx 저감을 위한SCR(Selective Catalytic Reduction) 촉매로의 적용 가능성을 확인하고자 하였다. 폐촉매와 단계별 처리된 RHDM 촉매를 대상으로 상압반응기상에서 NOx 저감 효율을 측정하였고, 촉매의 성분분석은 ICP, C & S analyzer 및 XRF를 이용하여 분석하였다. 10wt% 옥살산 수용액으로 바나듐을 침출한 촉매가 가장 안정적이었으며 높은 NOx 저감 효율을 보였다. 이를 메탈폼 형태의 지지체에 워시코팅한 촉매는 상용 SCR 촉매와 동등 수준의 NOx 저감 효율을 나타내었다. 따라서 폐 RHDM 촉매의 처리 조건 조정에 관한 후속 연구를 통하여 각 적용처에 적합한 SCR 촉매로의 이용 가능성은 충분할 것으로 사료된다.

This study was carried out considering that activated carbon physically adsorbs radon. Among the air cleaners equipped with activated carbon filter, eight air cleaners sold in Korea were selected and the radon reduction rate experiment was conducted. The instrument used an ionization chamber type instrument with a sensitivity of 3 CPM. The experiment was carried out by excluding the natural rate of reduction of radon in order to accurately grasp the radon reduction rate of activated carbon filter. Of the eight air purifiers, only three showed a reduction rate of more than 30%, while the remaining five air purifiers showed a reduction rate of less than 20%. This does not seem to be much different from the natural reduction rate. In addition, since it is not adsorbed by radon alone due to the nature of activated carbon, it is expected that the reduction rate will be lower in a real life environment.

Bloom of small centric diatom Stephanodiscus is quite occasional in winter season in temperate freshwater ecosystems. It often leads to degradation of water quality and affects the quality of supplied drinking water. In a previous study, we have found that naphthoquinone (NQ) 4-6 derivate is an effective tool for efficient mitigation of natural S. hantzschii blooms. In the present research, polylactide (PLA) and agar foam were used as immobilized agent for NQ 4-6 to improve the efficiency of NQ 4-6 compound releasing process for its application under various field conditions. Mesocosm experiments at 10 ton scale suggested that the abundance of S. hantzschii was continuously increased in the control and upon treatment of the mesocosm with immobilized NQ 4-6 from PLA and agar foam. Their algicidal activities were 78.8% and 77.1%, respectively, on S. hantzschii after 10 days. In the mesocosm experiments, the dynamics of biotic (bacteria, HNFs, ciliates, zooplankton) and abiotic (water temperature, dissolved oxygen, pH, conductivity, nutrients) factors remained unaffected. They exhibited similar trends in the control and treatment groups. Therefore, the immobilized NQ 4-6 from PLA and agar foam has potential to be used as an alternative algicidal substance to effectively mitigate natural S. hantzschii blooms under various field conditions. In addition, it not only can be used to control S. hantzschii, but also is an effective technique. The immobilized NQ 4-6 showed stable controlled release in desired system.

고분자막이 가진 수투과능 한계와 비가역적 막오염에 의한 효율 저하는 막기반 수처리공정의 추가적인 경쟁력 확보를 위해 해결해야 하는 문제이다. 본 연구에서는 초고속 물투과 특성과 뛰어난 선택성을 지닌 Graphene oxide (GO)막 에 뛰어난 항균성을 가진 은나노(nAg)가 코팅된 막을 제작, 평가하였다. GO막 은 막오염 저감에 효과적일 수 있는 높은 친수성과 음표면전하와 같은 특성과 막오염에 취약할 수 있는 높은 비표면적과 뛰어난 흡착능력과 같은 특성을 동 시에 가진다. 따라서, 논란의 부분이 있는 GO막의 막오염에 대한 저항성의 확실한 향상을 위해 nAg를 적용하였다.

본 연구에서는 LED 광원에 대하여 재실자의 업무 효율성과 에너지 저감 효과를 알아보기 위한 실험을 실시하 였다. 이를 위해 LED 광원의 특성인 펄 스 폭변조(PWM, pulse width modulation)와 조도(lux)를 제어하여 총 9가 지의 다양한 조명환경을 구성하였다. LED 조명의 펄스변조 비율은 각각 R:G:B=1:1:1, R:G:B=4:1:5, R:G:B=8:7:7 으로 하였으며, 조도는 각각 400 lx, 700 lx, 1000 lx 으로 설정하였다. 또한, 실내환경은 온도 20∼24℃, 습도 50∼ 60%, 착의량 1 clo 로 설정하였다. 각각의 주어진 9개의 조명환경에서 업무 효율성과 에너지 소비에 대해 분석하 였다. 업무 효율성 분석을 위해 오류검색수정 작업을 실시하였으며, 에너지 소비 분석을 위해 각 조명환경에서 누적 소비전력을 측정하였다. 제안한 조명환경을 통해 실험한 결과, 업무 효율성은 400 lx 보다 700 lx 이상에서 정확도 및 소요시간의 효율이 좋았으며, 소요시간의 경우 제안한 펄스변조 R:G:B=8:7:7 에서 가장 좋은 효율을 나타냈다. 또한, 각각의 조도에 대한 소비전력은 펄스변조 R:G:B=8:7:7 > RGB=1:1:1 > R:G:B=4:1:5의 순으로 낮게 나타났다. 따라서, 본 논문에서 제안한 펄스 폭 변조 효과가 업무효율성 및 에너지 저감에 영향을 미치는 것을 확인할 수 있었다.

PURPOSES : The purpose of this study is to assess removal efficiency of non-point pollutants and applicability for non-point pollutant reduction facilities by conducting the demonstration project operation. METHODS : In order to analyze removal efficiency of non-point pollutants for facilities such as a grassed swale, a small constructed wetland, a free water surface wetland, a horizontal sub-surface flow wetland, and a sand filtration, the field data including specifications of facilities, rainfall, inflow and runoff rainfall effluent etc. was acquired after occurring rainfall events, and the acquired data was analyzed for removal efficiency rate to assess road non-point pollutants facilities using event mean concentration (EMC) and summation of load (SOL) methods. RESULTS: The results of analyzing rainfall effluent, non-point pollutant sources showed that total suspended solid (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), chrome (Cr), zinc (Zn), and lead (Pb) can be removed through non-point pollutant reduction facilities by 60.3% ~ 100%. Especially removal efficiency of TSS, COD and BOD is relatively higher than removal efficiency of other non-point pollutant sources in all kind of non-point pollutant facilities. CONCLUSIONS : Based on the result of this study, even though natural type of non-point pollutant reduction facilities for roads occupy small areas comparing with drainage basin areas, most of non-point pollutant sources would be removed through the facilities.

The performance of the new aerobic digestion system combined with inorganic sludge separation unit and sludge solubilization unit, CaviTec II, is evaluated. Anaerobic digester effluent sludge is used for feed sludge of CaviTec II system. By addition of CaviTec II, the amount of cake generated is reduced by 27%, and the soluble nitrogen is reduced by 92%.

The performance of five kind adsorbents, which can reduce nitrogen oxide (NOx) from the diesel engine occupying 85% of the fishing boat, was carried out and the emission reduction filter was manufactured and evaluated in the adsorption efficiency of the emission gas for 240 KW diesel portable generator. As a NOx emission filter made of mordenite which has an excellent cation exchange capacity was manufactured by ball type adsorbents having excellent specific surface area. The adsorption efficiency of mordenite material applying the emission reduction filter began to show up at the operating time 10 minutes in comparison with the activated carbon and zeolite materials, and it was exposed to continue until 100% capability with passing by 20 minutes. So the adsorption efficiency of the NOx reduction filter consistently maintained at the averaged 80%.

본 연구는 고속도로 야생동물 유도울타리 설치효과를 분석하여 적정한 유도울타리 설치 개선 및 관리방안을 제시하고자 중앙고속도로 만종분기점~홍천나들목구간을 대상으로 수행하였다. 고속도로에 설치된 유도울타리는 포유류의 도로침입 방지효과가 있었으며, 방음벽, 낙석방지울타리, 2단 가드레일과 분리방호벽도 로드킬 예방에 효과적인 시설이었다. 유도울타리의 로드킬 저감 효과는 출입문이 설치된 높이 1.5m의 울타리보다 출입문이 설치되지 않은 높이 1.0m 구간이 로드킬 감소효과가 높아 출입문의 유무가 로드킬 저감에 중요한 요인으로 판단되었다. 또한 도로시설물의 연결지점에서 로드킬 저감 효과가 컸으며 출입문이 있더라도 관리가 잘되는 지역도 로드킬 감소효과가 높았다. 유도울타리는 설치연장이 증가함에 따라 로드킬 감소율이 높았다. 유도울타리 끝 부분과 절토부 주변은 로드킬에 취약하여 이에 대한 개선이 요구되었다. 울타리 유지관리용 출입문은 설치간격이 가까울수록 로드킬 발생량이 높아 출입문 관리가 로드킬 저감에 효과가 많은 것으로 판단되었다. 고속도로 유도울타리 설치 개선방안은 암반의 급경사 지역 외에 모두 설치되어야 하고, 도로상의 낙석방지책, 2단 가드레일, 방호벽 등은 적정 시설개선을 통해 유도울타리로 연결 설치되어야 한다. 출입문을 설치할 경우 자동개폐식 또는 중력개폐식으로 설치하여 개방을 방지하고 야생동물 탈출로가 조성이 되어야 한다. 겸용생물이동통로는 토양층 복원이나 식생공간을 조성하여 생물이동통로화 하여야하며 로드킬로 포식자에 의한 2차 로드킬을 막기 위해 사고난 사체는 즉시 도로외부로 처리가 되어야 한다. 울타리는 최소 사고예방 목표지점으로부터 양방향 500m 이상 즉 1,000m 이상 설치되어야 하며 가급적 다음 도로시설인 교량, 통로박스 등까지 연결하여 야생동물을 생물이동통로로 안전하게 유도하여야 한다.

The purpose of this study was to assess the removal efficiency of formaldehyde using carbon nano colloid (CNC) which was produced by comparatively easy and cheap method. In this study, carbon nano colloid based on water was produced by an electro‐chemical method. The particles which have mostly a spherical shape whose diameter was, what is called,‘nano‐size’were produced. Non‐woven fabric filter, which is currently on the market as a medium filter, was used for the removal efficiency test. Known concentration (0.5 ppm) of formaldehyde standard gas was used as a pollutant. The overall results indicate that (1) nanosize carbon colloids which have a stable dispersibility of which diameter is approximately 10 nm or less, (2) filters treated with carbon nano colloids showed higher removal efficiency, 44.47 ㎍ of HCHO removed/g of carbon and 19.28 ㎍ of HCHO removed/g of carbon, compared to the control experiment using a normal carbon filter, 1.45 ㎍ of HCHO removed/g of carbon.

This study aims to reduce the bycatch of young fishes and other species in the octopus(Octopus vulagris, Octopus dolfleini) trap fishery on the East Sea, Korea. We carried out field experiments and tank experiments to verify the fishing efficiency and bycatch with the different 8 types of trap. 4 of them had mesh size 20, 35, 55 respectively and 75mm, 2 of them with escape ring of diameter 30mm and 50mm and 2 of them with escape device. The gap was 20 and 40mm respectively. The mesh sizes of the traps with ring and frame were 20mm. The traps with mesh size 20 and 35mm were not reasonable because it could fish under 300g octopus as bycatch which is not permitted by the Korean fisheries regulations. The catch number of octopus over 300g by traps with escape ring of diameter 30mm was 53. The catch of trap with mesh size 20mm was 54. The catch of trap with mesh size 35mm was 53. There is no significant difference among them. The catch number of octopus over 500g that is fishermen's favorite one was 46 in the trap with escap ring. The diameter of was 30 mm and the catch of trap with mesh size 20mm was more 3 catch and the catch of trap with mesh size 35mm had 6 more catch. Fishermen wanted to catch over 500g octopus because the octopuses had commercial value. The traps with escape ring can be replaceable with he traps with mesh size 20 or 35mm because the trap is suitable to conserve the octopus resources and keep the fishermen's fishing substantiality.