• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.4
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• pp.86-96
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• 2012

Hydrogen gas production of anaerobic fermentative process from food waste as a substrate was 3.47 mg $H_2/g$ COD. The hydrogen production was little less than the synthetic wastewater with sucrose as a substrate (7.56 mg $H_2/g$ COD). The B/A ratios of the synthetic wastewater and food waste were 3.73 or 8.01 respectively. Butyric acid was more produced when hydrogen production was higher. Microbial community in the samples was analyzed as Escherichia sp., Klebsiella sp., Clostridium sp., Bacterium sp., and Enterobacter sp. Clostridium sp. was detected both samples but Klebsiella sp. was more active with fermentation process of the food waste. Taxonomic description shows that 60% of the microorganism was ${\gamma}-proteobacteria$ and Firmicute and Bacteria was 20% respectively.

• Journal of the Korean GEO-environmental Society
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• v.9 no.2
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• pp.23-29
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• 2008

It has been mentioned that CSTR (Completely Stirred Tank Reactor) and UASB (Upflow Anaerobic Sludge Blanket) processes, the existing anaerobic processes, have problems in the treatment of highly concentrated particulate organic wastewater (HCPOW). Therefore, this paper discusses the treatment possibility of distillery wastewater which is a typical HCPOW using ADEPT (anaerobic Digestion Elutriated Phased Treatment) process. In the comparison of CSTR and ADEPT, ADEPT produced much higher gas than that of CSTR removing more organic matters and suspended solids in ADEPT process, ADEPT had no effect on the decrease in pH by volatile fatty acids and showed steady pH in spite of relatively short HRT. In the results of removal rate according to recycle ratios between 6Qin and 2Qin in ADEPT, 6Qin showed high removal rate during the operation time. Therefore it appears that ADEPT had an applicability for the treatment of distillery wastewater. ADEPT could be a economical process, due to the short HRT, the energy recovery by the methane production, and the utilization for carbon source of produced organic acid from the ADEPT-acid reactor.

• Explosives and Blasting
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• v.40 no.4
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• pp.27-34
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• 2022

The government is promoting various policies to reduce greenhouse gas emissions for carbon neutrality, one of the key tasks is to revitalize the hydrogen economy. As one of these policies the government has formulated a plan to incorporate hydrogen into existing city gas pipes, and aims to commercialize 20% hydrogen mixing by 2026. In preparation for the commercialization of city gas and hydrogen mixture, this study quantitatively predicts the scale of damage and the range of impact in the event of leakage of these two gas mixtures. The quantitative damage prediction method is to calculate the damage conversion distance through the calculation of the TNT equivalent by setting the leakage amount of the gas mixture in the event of an accident under a virtual scenario.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.365-365
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• 2023

우리나라는 지리, 지형 및 기상특성으로 인해 집중호우와 태풍 등으로 자연재해 피해를 입고 있으며, 재해예방사업의 일환으로 1998년부터 자연재해위험개선지구 정비사업을 통해 자연재해로부터 침수, 유실, 붕괴위험 등 피해예방을 위해 노력하고 있다. 서울특별시는 도시화로 인한 우수침투 가능지역 감소와 유역경사 부족에 따른 충분한 관거 경사확보의 어려움으로 저지대에 노면수가 집중되면서 대규모 침수피해(2010. 09, 2011. 07)가 발생되었으며, 신월·신정지구 및 화곡2지구가 자연재해위험개선지구로 선정(2011. 04), 침수방지를 위한 대책으로 국내 최초의 대규모 터널형 빗물저류배수시설(신월빗물저류배수시설)을 준공(2020. 05)하였다. 본 연구에서는 신월빗물저류배수시설 설치에 따른 상습침수구역의 사업 전·후 침수피해 저감효과 검증을 위해 도시유출모형을 구축하여 서울시 방재성능목표 확보여부를 판단하고자 하였다. 기존 설계 당시 서울시 방재성능목표(30년 빈도, 95mm/hr)는 확보되었으나 이를 초과하는 강우(2010. 09, 98.5mm/hr)가 발생함에 따라 수행된 추가 분석(100mm/hr) 결과, 유역의 침수 완전해소를 위해서는 빗물저류배수시설과 더불어 국부적인 간선관거 개량의 필요성이 제시되었다. 이에 따라 본 연구에서는 도시유출모형 구축 시 최근 개선된 하수관로, 지형특성, 홍수량산정표준침(2019, 환경부)등에 따른 수리·수문특성을 반영하고, 신일펌프장(간이)을 추가적으로 고려하여 현재 기준에서의 침수피해 저감 효과를 면밀이 분석하였으며, 그 결과 서울시 방재성능목표 뿐만 아니라 100mm/hr에도 침수가 완전 해소되는 것으로 나타났다. 신월빗물저류배수터널 설치에 따른 침수피해 저감효과 평가 및 분석결과를 통해 자연재해위험개선지구의 해제가 가능할 것으로 판단되며, 지역안전·환경효과, 주민만족도 등 다양한 항목에 대하여 상습침수구역 내 주민설문조사를 수행한 결과 신월빗물저류배수터널에 대한 만족도가 충분히 제고된 만큼 향후 시설의 기능적, 운영적 측면에서의 유지관리가 잘 이루어진다면 침수로부터 안전한 도시를 구현하는데 큰 역할을 할 것으로 기대된다.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.320-332
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• 2013

The feed air to MSW incinerator influences on the residence time of combustion gas, removal of unburnt ash and exiting gas temperature. Thus the secondary air volume could present sufficient residence time which can maintain the exiting temperature over $850^{\circ}C$. The secondary air also relates directly with the turbulence in the inside of combustion chamber, which finally provide the stable combustion condition. The present study designed a modern incinerator for a field scale, and evaluation of the potential amount of primary air based on the daily combustible quantity. From the evaluated primary air volume, the secondary air flow rate could be estimated, and its dynamic behavior was verified. In addition, the obtained air volume enables to find an optimum operation condition of the combustion. As a result of the CFD simulation, the air ratio 75 : 25 between primary and secondary air amount was optimum ratio than design criteria 72 : 28. And the flow velocity ratio of front-back of secondary air jet nozzle was found excellent at 1 : 3. In addition, the result of applied to the plant, the removal efficiency of NOx and CO generation would concentration of CO.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.7
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• pp.432-440
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• 2015

Biochar, a by-product from pyrolysis of biomass, is a promising option to mitigate climate change by increasing soil carbon sequestration. This material is also considered to have potential to remediate a soil with heavy metal pollution by increasing the soil's adsorptive capacity. This study conducted the assessment of two biochars considering the climate change mitigation potential and heavy metal removal capacity at the same time. Two kinds of biochars (BC_Ch, TW_Ch) were prepared by pyrolyzing the biomass of burcucumber (BC_Bm) and tea waste (TW_Bm). The soils polluted with Pb were mixed with biochars or biomass and incubated for 60 d. During the incubation, $CO_2$, $CH_4$, and $N_2O$ were regularly measured and the soil before and after incubation was analyzed for chemical and biological parameters including the acetate extractable Pb. The results showed that only the BC_Ch treatment significantly reduced the amount of Pb after 60 d incubation. During the incubation, the $CO_2$ and $N_2O$ emissions from the BC_Ch and TW_Ch were decreased by 24% and 34% compared to the BC_Bm and TW_Bm, respectively. The $CH_4$ emissions were not significantly affected by biochar treatments. We calculated the GWP considering the production of amendment materials, application to the soils, removal of Pb, and soil carbon storage. The BC_Ch treatment had the most negative value because it had the higher Pb adsorption and soil carbon sequestration. Our results imply that if we apply biochar made from burcucumber, we could expect the pollution reduction and climate change mitigation at the same time.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.797-806
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• 2000

The objectives were to compare the biodegradable threshold concentrations of phenol with the different composition of the influent carbon source and examine the SMA (Specific Methanogenic Activity)and the possibility of simultaneous removal of high-strength organics and nitrogen compounds in UASB(Upflow Anaerobic Sludge Blanket) - PBR(Packed Bed Reactor) process. The results showed that UASB reactors were efficient to remove phenol and phenol + glucose from synthetic wastewater. At phenol conc, of 600 mg/L and SCOD conc. of 2100 mg/L in UASB reactor(with only phenol as substrate), the removal efficiencies of phenol and SCOD were over 99% and 93% respectively, under MLVSS of 20 g. The activity of microorganism was $0.112g\;phenol/g\;VSS{\cdot}d$, $0.351g\;SCOD/g\;VSS{\cdot}d$. The gas production rate was $0.115L/g\;VSS{\cdot}d$ and $CH_4$ content in gas was about 70%. At phenol conc. of 760 mg/L and SCOD conc. of 4300 mg/L in UASB reactor( with phenol + glucose as substrates), the removal efficiencies of phenol and of SCOD were over 99% and 90% respectively, under MLVSS of 20 g. The activity of microoganism was $0.135g\;phenol/g\;VSS{\cdot}d$, $0.696g\;SCOD/g\;VSS{\cdot}d$. The gas production rate was $0.257L/g\;VSS{\cdot}d$ and $CH_4$ content in gas was about 70%. Serum bottle test showed that the activity of granule was inhibited over 1600 mg/L phenol conc, and denitrification and methanogenesis simultaneously took place in UASB granules under co-substrates conditions. PBR reactor packed with cilium type media, was efficient in nitrification. In condition of $0.038kg\;NH_4-N/m^3-media{\cdot}d$. 10~12 mg/L phenol conc. and 200~500 mg/L SCOD conc., nitrification efficiency was over 90% and phenol removal efficiency was over 98%.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.110-115
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• 2003

The iufluence of abandonment of agricultural fields on soil carbon and nitrogen dynamics is rarely addressed due to lack of appropriately paired sites. In this study, we identified three sites that have native forest and abandoned rice and crop fields at Mt. Kumdan near Seoul. Currently the vegetation of indigenous forest and the abandoned rice field is deciduous hardwood forest, while that of the abandoned crop field is deciduous shrub. We measured soil $CO_2$ evolution and inorganic N availability for the three sites from 25 July 2002 through 24 January 2003. Soil $CO_2$ evolution tracked seasonal soil temperature. Mean soil $CO_2$ evolution (g $CO_2$/$m^2$/hr) for the study period was 0.42 for the rice field to forest, 0.50 for the crop field to shrub, and 0.41 for the indigenous forest, respectively. Soil $CO_2$ evolution and soil temperature were not different among the sites; however, soil water content was significantly different. Soil water content had a very weak influence on soil $CO_2$ evolution. Inorganic resin N availability differed among the three sites and seemed to be related to soil moisture.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.77-90
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• 2022

Despite the decreasing trend of anthropogenic emissions in East Asia in recent years, haze days still frequently occur in spring. Atmospheric blocking, which occurs frequently in the northeastern Pacific, leads to persistent changes in large-scale circulation and blocks westerly flow in the East Asian region. During March 2019, frequent warm and stagnant synoptic meteorological conditions over East Asia were accompanied 6-7 days later by the Alaskan atmospheric blocking. The Alaskan atmospheric blocking over the period of March 18-24, 2019 led to high particulate matter (PM₁₀) severe haze days exceeding a daily average of 50 ㎍ m^-3 over the period of March 25-28, 2019 in South Korea. Although the high-PM₁₀ severe haze days were caused by warm and stagnant meteorological conditions, the regional contribution of anthropogenic emissions in eastern China was calculated to be 30-40% using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem). The major regional contributions of PM₁₀ aerosols in the period of high-PM₁₀ severe haze days were as follows: nitrates, 20-25%; sulphates, 10-15%; ammonium, 5-10%; and other inorganics, 15-20%. Ammonium nitrate generated via gas-to-aerosol conversion in a warm and stagnant atmosphere largely contributed to the regional transport of PM₁₀ aerosols in the high-PM₁₀ severe haze days in South Korea.

• Journal of the Society of Disaster Information
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• v.18 no.2
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• pp.324-332
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• 2022

Purpose: In order to conduct a spontaneous ignition test in which a fire occurs in the absence of an ignition source due to the oil adsorbed on the towel. A phenomenon in which spontaneous ignition occurs when adsorbed to fibers using flaxseed oil, which is drying oil and olive oil, which is non-drying oil, is tested through an experiment. Method: After placing the sample container in the experimental device, observe the change in the central temperature of the sample, and when the central temperature rises above the set temperature and a fire occurs, it is judged as "ignition", and the experiment is stopped after checking the maximum value of the central temperature of the sample,When the central temperature of the sample was maintained similar to the set temperature, it was judged as "non-ignition" and the experiment was stopped. Result: In the towels with adsorbed flaxseed oil, the temperature in the sample container increased rapidly and combustion occurred in sheets 5, 10, and 15. Olive oil is a non-drying oil, does not ignite because it is difficult to dry because carbon is a single bond and it is difficult to bond with oxygen. Conclusion: It was confirmed that the more the amount of towel adsorbed to the drying oil, flaxseed oil, the longer the time to reach the set temperature and the occurrence of ignition.