• 대한환경공학회지
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• 제28권4호
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• pp.453-458
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• 2006

수질의 빠르고 정확한 COD(Chemical Oxygen Demand)의 측정을 위하여 전극표면 연마장치가 부착된 전기화학적 측정 센서시스템을 연구하였다. 수질 내 유기물에 대한 Cu의 산화작용이 COD 측정의 기본원리로 이용되었으며, 3전극계를 적용한 전기화학 셀을 COD 측정시스템에 적용하였다. 장시간의 COD 측정에 대비하여, Cu전극의 내구성과 안정성을 유지시키기 위해 회전되는 연마석을 이용한 자동연마장치를 부착하였다. 유기물을 함유한 인공시료 및 실제 현장시료를 이용하여 COD 변화에 대한 측정가능성을 실험하였고, $COD_{Mn}$ 수치와 COD 측정용 센서를 이용하여 측정한 Coulombic yield와의 사이에 높은 상관관계($r^2=0.93$)를 가지며 이 측정값을 EOD(electrochemical oxygen demand)로 표현할 수 있다는 것을 확인하였다. 이러한 측정 결과를 토대로 이 시스템이 폐수처리장 및 하수에 연속 COD 측정 장치로 적용할 수 있는 가능성이 있을 것으로 확인하였다.

• Safety and Health at Work
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• 제2권3호
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• pp.210-217
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• 2011

Objectives: The purpose of this study was to measure the concentration of volatile organic compound (VOC)s originated from the chemicals used and/or derived from the original parental chemicals in the photolithography processes of semiconductor manufacturing factories. Methods: A total of four photolithography processes in 4 Fabs at three different semiconductor manufacturing factories in Korea were selected for this study. This study investigated the types of chemicals used and generated during the photolithography process of each Fab, and the concentration levels of VOCs for each Fab. Results: A variety of organic compounds such as ketone, alcohol, and acetate compounds as well as aromatic compounds were used as solvents and developing agents in the processes. Also, the generation of by-products, such as toluene and phenol, was identified through a thermal decomposition experiment performed on a photoresist. The VOC concentration levels in the processes were lower than 5% of the threshold limit value (TLV)s. However, the air contaminated with chemical substances generated during the processes was re-circulated through the ventilation system, thereby affecting the airborne VOC concentrations in the photolithography processes. Conclusion: Tens of organic compounds were being used in the photolithography processes, though the types of chemical used varied with the factory. Also, by-products, such as aromatic compounds, could be generated during photoresist patterning by exposure to light. Although the airborne VOC concentrations resulting from the processes were lower than 5% of the TLVs, employees still could be exposed directly or indirectly to various types of VOCs.

• 생물환경조절학회지
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• 제30권1호
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• pp.37-45
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• 2021

본 연구는 식물공장에서 고흡수성 합성고분자(Super absorbent polymer; SAP)를 수경재배에서 배지로서의 활용가능성을 구명하고자 홍화 및 아마란스 새싹의 생육특성과 페놀함량 및 항산화도를 평가하였다. 대조구는 새싹 재배기(19 × 14 × 9cm, W × D × L)에 거즈를 깔고, 처리구에는 거즈 위에 SAP를 추가하여 비교 분석하였다. 홍화 새싹 종자를 30℃의 증류수에 5시간 동안침지한 뒤, 새싹 재배기에 파종 후 식물생장상에서 재배하였다. 식물생장상의 내부 온도는 25 ± 1℃, 습도는 70 ± 4%로 유지되었고 광조건은 35 ± 6μmol·m-2·s-1(광주기 12h)로 설정하였다. 아마란스 새싹은 새싹 재배기에 파종 후 식물생장상 내부 온도 25 ± 2℃, 습도는 70 ± 5%, 광조건은 188 ± 10μmol·m-2·s-1(광주기 16h)로 설정하였다. SAP의 기본적인 특성으로 물리/화학적 분석과 홍화 및 아마란스의 발아율과 생육특성 및 기능성 물질을 분석하였다. 홍화는 발아율, 생육 및 기능성 물질에서 처리구와 대조구간 차이가 없었으나, 아마란스는 생육 측면에서는 대조구와 차이가 없었으나 발아율, 건물중, 페놀함량 및 항산화도에서 처리구가 각각 1.16배, 1.16배, 1.40배, 1.12배의 높은 결과를 보였다. 결과적으로, 이번 연구를 통해 식물공장에서 SAP을 활용한 새싹재배가 가능할 것으로 판단하였으며 추후 SAP가 식물 생리적으로 작용하는 연구가 필요할 것으로 사료된다.

• Geomechanics and Engineering
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• 제15권5호
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• pp.1091-1100
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• 2018

In this study, the relationships between hydraulic conductivity of GCLs and physico-chemical properties of bentonites were assessed. In addition to four factory manufactured GCLs, six artificially prepared GCLs (AP-GCLs) were tested. AP-GCLs were prepared in the laboratory without bonding or stitching. A total of 20 hydraulic conductivity tests were conducted using flexible wall permeameters ten of which were permeated with distilled deionized water (DIW) and the rest were permeated with tap water (TW). The hydraulic conductivity of GCLs and AP-GCLs were between $5.2{\times}10^{-10}cm/s$ and $3.0{\times}10^{-9}cm/s$. The hydraulic conductivities of all GCLs to DIW were very similar to that of GCLs to TW. Then, simple regression analyses were conducted between hydraulic conductivity and physicochemical properties of bentonite. The best correlation coefficient was achieved when hydraulic conductivity was related with clay content (R=0.85). Liquid limit and plasticity index were other independent variables that have good correlation coefficients with hydraulic conductivity (R~0.80). The correlation coefficient with swell index is less than other parameters, but still fairly good (R~0.70). In contrast, hydraulic conductivity had poor correlation coefficients with specific surface area (SSA), smectite content and cation exchange capacity (CEC) (i.e., R < 0.5). Furthermore, some post-test properties of bentonite such as final height and final water content were correlated with the hydraulic conductivity as well. The hydraulic conductivity of GCLs had fairly good correlation coefficients with either final height or final water content. However, those of AP-GCLs had poor correlations with these variables on account of fiber free characteristics.

• 생물환경조절학회지
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• 제8권2호
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• pp.83-89
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• 1999

여름철 고온기에 반결구상추를 식물공장에서 재배할 때 자주 발생하는 잎끝마름증 현상을 경감시키고, 생산성을 향상시키기 위해 품종, 육묘배지, 베드 기울기, 베드위치, 급액량과 같은 최적의 재배조건을 구명하기 위하여 실험을 수행하였다. Rex와 Flandria 품종은 다른 품종에 비해 비록 생육은 약간 저조했으나 상품성이 높고, 잎끝마름증 발생율이 적어 여름철 고온기에 적합한 품종인 것으로 나타났다. 육묘배지는 물리, 화학적 특성이 우수한 코코피트에서 상추의 생육량이 높았으며, 근권부에 배양액의 흐름을 원활하게 해 줄 수 있는 베드의 기울기는 l~2%가 적당하였다. 급액량은 반결구상추 생육에서 베드당 2$\ell$가 적합하였다 베드설치 높이에 따른 반결구상추 생육은 베드의 높이가 낮을 때가 높을 때보다 좋았다. 이것은 베드높이를 낮게 설치함으로써 작물주변의 온도와 습도분포가 결구상추의 생육에 적합하였기 때문인 것으로 생각되었다.

• 한국환경보건학회지
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• 제27권1호
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• pp.93-99
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• 2001

This study aims at finding out pertinent reaction conditions for treating high concentration ammonia contained in N-chemical factory wastewater with decompressed ammonia stripping method that was designed. And it also tries to investigate adsorption capability of removed ammonia to soil. The results from experiments are as follows ; 1. The removal rate of N $H_3$-N of synthetic wastewater was under 85% at pH 10 with decompressed ammonia stripping method. The reaction time in pressure 360 mmHg at pH 11 and 12 was shorter than in 460 mmHg, and the removal rate of N $H_3$-N with decompressed ammonia stripping method at 9$0^{\circ}C$ was 11~15% higher than air stripping 2. The optimum conditions for decompressed ammonia stripping with synthetic sample were shown as pH 12, temperature 9$0^{\circ}C$, internal reaction pressure 460 mmHg and reaction time 50 minutes. These conditions were applied to treat the wastewater containing organic-N 290.5mg/$\ell$, N $H_3$-N 168.9mg/$\ell$, N $O_2$-N 23.2mg/$\ell$, N $O_3$-N 252.4mg/$\ell$, T-N 735mg/$\ell$. Organic-N turned out to be removed 60%, the removal rate of N $H_3$-N IS 94%, T-N is 50%. But N $O_2$-N and N $O_3$-N were increased with 7.8% and 14.9% respectively. 3. The CO $D_{Sr}$ removal rate in decompressed ammonia stripping reaction was 42% and S $O_4$$^{2-}$ was removed 8.2%. It was turned out caused with higher pH and thermolysis. 4. In soil adsorption of ammonia desorbed from the decompressed stripping process of wastewater, the recovery rate was 76% in wet soil.

• 한국환경보건학회지
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• 제40권1호
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• pp.27-37
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• 2014

Objectives: On September 27, 2012, leakage of anhydrous hydrofluoric acid occurred in a chemical plant in the Gumi National Industrial Complex. Following the accident, local factory workers and residents complained of abnormal health conditions. In addition, visual discolorations were widely observed in crops and trees in surrounding areas. The main objectives of the present study were to identify the area that was affected by the spill using data obtained from plants, soil, and water samples after the accident. Methods: Fluoride concentrations were analyzed in pine tree needles, soil, nearby streams, ponds and reservoirs collected from an area within a radius of three kilometers from the plant where the leak occurred. Fluoride concentrations in the air at the time of leakage were then estimated from fluoride concentrations that were measured in the pine tree needles. A Kriged map was developed to describe the spatial distribution of hydrofluoric acid at the time of the leakage and was compared with the area designated as a Special Disaster Zone by the government. Results: The Special Disaster Zone did not include all the affected area that was estimated by the Kriged map. Analytical results of the environmental samples also supported this discrepancy. Conclusion: Using plants, atmospheric concentrations of fluoride at the time of the leakage could be estimated. For the area that was identified as affected, further public health risk assessment and environmental risk assessment should be considered. Also, in the absence of air monitoring at the time of leakage, studies employing plants may be conducted in order to better understand the spatial extent and severity of the contamination.

• 한국산학기술학회논문지
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• 제11권12호
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• pp.5157-5164
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• 2010

국내의 폐석회는 약 320만 톤이 적치되어 있고 매년 약 10만 톤이 발생하고 있다. 본 연구에서는 도로노반 성토재로서의 재활용을 위한 폐석회 혼합토의 특성에 대하여 일련의 실험을 수행하였다. 시험에 사용한 폐석회는 인천의 모 화학공장에서 소다회($Na_2CO_3$)를 생산하는 공정에서 부수적으로 발생하는 부산물이다. 화강풍화토, 점토, 쇄석에 폐석회를 일정비율로 혼합한 폐석회 혼합토에 대하여 비중시험, 입도분석, Atterberg시험, 다짐시험, 일축압축시험, CBR, 투수시험, 전단시험, 마모시험, 및 모래당량시험을 실시하였다. 시험결과를 토대로 폐석회 혼합토는 폐석회를 20%정도 혼합하였을 때, 도로의 노반성토재의 품질기준을 만족하는 것으로 나타났다.

• 멤브레인
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• 제17권3호
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• pp.191-196
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• 2007

본 연구에서는 경도 이온의 화학적 침전을 위하여 지하수에 과량의 Lime-Soda ash를 주입하여 플럭(floc)을 형성한 다음 침전과정을 십자흐름(Crossflow) 방식의 관형 세라믹 분리막을 이용한 한외여과(UF) 공정으로 대체하였다. 그 결과 두유 포장팩 세척수로 사용하고 있는 지하수의 총경도를 10 mg/L as $CaCO_3$ 이하로 감소시킬 수 있었다. 한편, TMP(Trans-membrane pressure) 및 유량 변화 실험에서 투과선속(Permeate flux, J) 및 무차원한 투과선속($J/J_0$) 변화를 조사하여, TMP 및 유량이 무기물로 형성된 응집 플럭에 의한 막오염에 미치는 영향을 알아보았다. 그 결과, 본 실험 범위에서 TMP 및 유량 변화가 막오염과 총경도 제거율에 미치는 영향은 거의 없었다.

• 농업과학연구
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• 제43권2호
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• pp.215-220
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• 2016

The global cultivation area of genetically modified crops (GM crops) has been increasing every year. Cultivation of GM crops is not only beneficial to the economy but also has positive effects on the environment in decreasing the use of agrochemicals, chemical fertilizers, and agricultural machinery. However, there have been controversies about the admixture of GM crops and non-GM crops and the unintentional release of GM crops to the environment. Especially in Korea, where consumption of agricultural products is import-dependent, the economic importance of GM crops has been a significant issue. The Act on import and distribution of GM crops was established in 2001 to start the management of GM crops in Korea. Recently, the imported amount of GM crops to Korea has reached over 10 million tons and is increasing very rapidly; consequently, the potential environmental impact of GM crops is becoming a big issue in Korea. In Japan, the discovery of imported GM canola plants around ports in 2005 raised awareness of the unintentional release of GM crops. In Korea, GM maize plants were also found in port and feed factory surroundings from 2005 to 2007. It is now necessary to monitor imported GM crops by tracing distribution, transport process for practical environmental risk assessment. Possible gene transfer from GM crops to non-GM crops should also be investigated in the cultivation area and the surroundings as well.