• 한국식품위생안전성학회지
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• 제38권5호
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• pp.287-296
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• 2023

세계적으로 버섯에 대한 소비는 매년 증가하고 있으며 한국에서는 느타리버섯, 양송이버섯, 팽이버섯이 주로 유통되고 있다. 하지만, 버섯의 재배와 가공 과정에서 미생물 오염을 예방하기 위한 대안의 부재로 인하여 Listeria monocytogenes와 같은 병원성 미생물의 오염이 검출되고 있으며 버섯에 의한 식중독 및 리콜 사례가 다수 보고되고 있다. 버섯에서 오염된 미생물을 저감화하는 방법으로는 화학적 및 물리적 처리, 또는 이들을 결합하여 사용하는 병용처리 방법이 이용되고 있다. 화학적 처리로는 염소 혼합물, 과산화아세트산, 4차 암모늄이온 화합물이 주로 사용되고 있으며 오존과 전해수를 이용한 방법도 최근에 개발되었다. 물리적 처리로는 초음파, 방사선조사, 콜드 플라즈마 기술이 이용되고 있으며, 병용처리 방법으로는 자외선/염소 혼합물, 오존/유기산, 초음파/유기산 등이 연구되었다. 본 리뷰에서는 국내에서 소비되는 버섯의 종류와 그에 대한 미생물 오염도를 조사하고, 버섯에 오염된 미생물을 제어할 수 있는 기술에 대하여 조사하여, 정리하였다.

• 유기물자원화
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• 제13권1호
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• pp.115-123
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• 2005

본 논문은 PET의 하나인 물질재활용에 대해 전과정평가기법을 이용하여 환경성을 평가하였다. 이를 위하여 국내에서 재생업체를 대상으로 데이터를 수집하여 목록분석을 실시한 후 Eco-Indicator 95의 영향평가방법을 사용하여 각 영향범주별 환경영향을 분석하여 다음과 같은 결론을 얻었다. 폐플라스틱의 물질재활용공정에서 가장 영향을 미치는 것은 지구온난화로 밝혀졌다. 이는 폐플라스틱인 PET에 대해 물질재활용의 각 단위공정별 환경영향평가 결과에서 전력과 에너지를 가장 많이 사용하는 용융 및 재생원료화공정의 환경부하가 매우 높기 때문인 것으로 나타났다. 환경오염물질 배출량을 살펴보면 $CO_2$가 매우 높은 비중을 차지하였으며, 그 다음은 NOx이었다. 이는 전력사용과 수송과정의 경유사용에 기인한 것이다. 폐플라스틱의 물질재활용에 대한 영향평가결과는 오존층 파괴의 영향을 제외한 거의 모든 영향범주들이 음(-) 값이며 이는 환경성이 매우 좋은 것으로 나타났다. 또한, PET를 물질재활공정과 이를 다시 재생원료로서 사용할 경우를 비교할 때 환경부하삭감효과는 매우 크게 나타났다.

• 대기
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• 제27권4호
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• pp.423-433
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• 2017

The spatial and temporal variations in radiative forcing (RF) and mean temperature changes of greenhouse gases (GHGs), such as $CO_2$, $CH_4$, and $N_2O$, were analyzed at urban center (Yeon-dong) and background sites (Gosan) on Jeju Island during 2010~2015, based on a modeling approach (i.e., radiative transfer model). Overall, the RFs and mean temperature changes of $CO_2$ at Yeon-dong during most years (except for 2014) were estimated to be higher than those at Gosan. This might be possibly because of its higher concentrations at Yeon-dong due to relatively large energy consumption and small photosynthesis and also the difference in radiation flux due to the different input condition (e.g., local time and geographic coordinates of solar zenith angle) in the model. The annual mean RFs and temperature changes of $CO_2$ were highest in 2015 ($2.41Wm^{-2}$ and 1.76 K) at Yeon-dong and in 2013 ($2.22Wm^{-2}$ and 1.62 K) at Gosan (except for 2010 and 2011). The maximum monthly/seasonal mean RFs and temperature changes of $CO_2$ occurred in spring (Mar. and/or Apr.) or winter (Jan. and/or Feb.) at the two sites during the study period, whereas the minimum RFs and temperature changes in summer (Jun.-Aug.). In the case of $CH_4$ and $N_2O$, their impacts on the RF and mean temperature changes were very small (an order of magnitude lower) compared to $CO_2$. The spatio-temporal differences in these RF values of GHGs might primarily depend on the atmospheric profile (e.g., ozone profile), surface albedo, local time (or solar zenith angle), as well as their mass concentrations.

• 한국태양에너지학회 논문집
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• 제33권1호
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• pp.15-23
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• 2013

In this study, thermodynamic performance of R435A is examined both numerically and experimentally in an effort to replace HFC134a used in the refrigeration system of domestic water purifiers. Even though HFC134a is used predominantly in such a system these days, it needs to be phased out in the near future in Europe and most of the developed countries due to its high global warming potential. To solve this problem, cycle simulation and experimental measurements are carried out with a new refrigerant mixture of 20%R152a/80%RE170 using actual domestic water purifiers. This mixture is numbered and listed as R435A by ASHRAE recently. Test results show that the system performance with R435A is greatly influenced by the amount of charge due to the small internal volume of the refrigeration system of the domestic water purifiers. With the optimum amount of charge of 21 to 22 grams, about 50% of HFC134a, the energy consumption of R435A is 11.8% lower than that of HFC134a. The compressor discharge temperature of R435A $8^{\circ}C$ lower than that of HFC134a at the optimum charge. Overall, R435A, a new long term environmentally safe refrigerant, is a good alternative for HFC134a requiring little change in the refrigeration system of the domestic water purifiers.

• 한국물환경학회지
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• 제24권5호
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• pp.537-542
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• 2008

Textile industry has been recognized as an important pollution source due to its consumption of large volumes of water and chemicals. Textile wastewater contains very diverse chemicals in types and composition, among them the presence of dyes is highly visible and undesirable. In spite of these problems, there has not been a proper control for the wastewater because many dyes are difficult to be degraded or decolorized due to their complex structure and synthetic characteristics. This study has been progressed to evaluate more easily the potential decolorization of advanced treatment processes. It has been surveyed with the Y textile complex wastewater treatment plant, the raw wastewater has appeared very difficult biodegradability by 4.7 of $CODcr/BOD_5$ and 1,158.9 degree of color. In view of CODcr fractions, biodegradable COD portion was 46.4%, colloidal COD and real soluble COD was 45.3% and 31.5% each others. From research on unit processes, the degradable coefficient (k) became from 0.065 to $0.125d^{-1}$ by the processes, the decolorization appeared best efficiency by 30.1% (458.4 degree) in pre-ozone process. On the effluent from the biological process, the filterable CODcr became 129.3 mg/L, the biodegradable portion appeared 64.7% (83.6 mg/L), and the fixed dissolved solid (FDS), non-reactivity (NR), appeared very heavy portion by 80.5% (1,659.0 mg/L).

• 설비공학논문집
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• 제21권2호
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• pp.109-117
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• 2009

In this study, thermodynamic performance of R430A is examined both numerically and experimentally in an effort to replace HFC134a used in the refrigeration system of domestic water purifiers. Even though HFC134a is used predominantly in such a system these days, it needs to be phased out in the near future in Europe and most of the developed countries due to its high global warming potential. To solve this problem, cycle simulation and experimental measurements are carried out with a new refrigerant mixture of 76%R152a124% R600a using actual domestic water purifiers. This mixture is numbered and listed as R430A by ASHRAE recently. Test results show that the system performance with R430A is greatly influenced by the amount of charge due to the small internal volume of the refrigeration system of the domestic water purifiers. With the optimum amount of charge of 21 to 22 grams, about 50% of HFC134a, the energy consumption of R430A is 13.4% lower than that of HFC 134a. The compressor dome and discharge temperatures and condenser center temperature of R430A are very similar to those of HFC134a at the optimum charge. Overall, R430A, a new long term environmentally safe refrigerant, is a good alternative for HFC134a requiring little change in the refrigeration system of the domestic water purifiers.

• 한국물환경학회지
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• 제37권3호
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• pp.168-174
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• 2021

Mixing is a very important unit in water treatment process. A mechanical stirring method is generally used for mixing, but recently, the use of pressurized water mixing method (pump diffusion flash mixer) has gained interest because it is more advantageous in terms of mixing time, noise, energy consumption, and maintenance. The following conclusions were obtained from the study of pressurized water mixing method by Computational Fluid Dynamics. Firstly, the mixing degree in the pipe increased as the density of water increased. Secondly, even if the relative velocity between flow rate in the pipe and the pressurized water was constant, the mixing degree decreased as the flow velocity in the pipe increased. Thirdly, the stronger the injection energy the higher the mixing degree. It was also found that the mixing degree was greatly affected by the injection velocity as compared to the injection flow amount. Finally, the required energy to achieve 95% mixing degree at the distance of 10 times diameter in big pipes of 500 mm to 3000 mm was 0.3 to 4.5 kJ. The result of this study could be used in the process design of injection with water purification chemicals, such as, ozone, chlorine, and coagulant.

• 상하수도학회지
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• 제36권2호
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• pp.59-79
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• 2022

Conventional wastewater treatment plants (WWTPs) do not fully remove micropollutants. Enhanced treatment of sewage effluents is being considered or implemented in some countries to minimize the discharge of problematic micropollutants from WWTPs. Representative enhanced sewage treatment technologies for micropollutant removal were reviewed, including their current status of research and development. Advanced oxidation processes (AOPs) such as ozonation and UV/H₂O₂ and adsorption processes using powdered (PAC) and granular activated carbon (GAC) were mainly discussed with focusing on process principles for the micropollutant removal, effect of process operation and water matrix factors, and technical and economic feasibility. Pilot- and full-scale studies have shown that ozonation, PAC, and GAC can achieve significant elimination of various micropollutants at economically feasible costs(0.16-0.29 €/m³). Considering the current status of domestic WWTPs, ozonation and PAC were found to be the most feasible options for the enhanced sewage effluent treatment. Although ozonation and PAC are all mature technologies, a range of technical aspects should be considered for their successful application, such as energy consumption, CO₂ emission, byproduct or waste generation, and ease of system construction/operation/maintenance. More feasibility studies considering domestic wastewater characteristics and WWTP conditions are required to apply ozonation or PAC/GAC adsorption process to enhance sewage effluent treatment in Korea.

• 한국물환경학회지
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• 제38권6호
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• pp.267-274
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• 2022

This paper is a result of research conducted on the 800,000 m³/d capacity of A Water Treatment Plant (WTP) and 400,000 m³/d capacity of B WTP plant in operation in the Nakdong River region. We evaluated the effect of algae broom on the WTP operation based on the running data of both WTP and the data on the pre-oxidation process field test for algae control using sodium permanganate (SPM) at the B WTP. The study results showed that during the algal bloom period, the coagulant dose increased by 102% in A WTP and 58% in B WTP, respectively, and the chlorine dose also increased by 38% and 29%, respectively, which may affect Total trihalomethane (THM) production. Data such as algal populations and Chl-a, residual chlorine and THM, algal populations, and ozone dose appeared also highly correlated, confirming that algal broom affects WTP operations, including water quality and chemical dosage. As a result of the field test of B WTP, THMs appeared lower than that of the control, suggesting the possibility of the SPM pre-oxidation process as an alternative to algae-related water quality management. Furthermore, in terms of GHG emissions due to energy consumption, it was observed that the pre-oxidation process using SPM was approximately 10.8%, which is a very low ratio compared to the pre-ozonation process. Therefore, these results suggest that the SPM pre-oxidation process can be recommended as an alternative to low-carbon water purification technology.

• 한국대기환경학회지
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• 제2권3호
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• pp.1-10
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• 1986

Nowadays, air pollution by increasing consumption of fossil fuels resulting from rapidly growing population and industrialization has caused the adverse effects on terrestrial ecosystems and become one of the most serious problems causing environmental discriptions. Air pollution such as $SO_2, HF, NO_X,$ fly ash, ozone and PAN might influence plant growth, reproduction, nutrient cycling, photosynthesis and predisposition to entomological and pathological stresses on plants. Furthermore, accumulation of those toxic substances in forests might cause subtle or serious changes in the structure and function of forest ecosystems. Since 1970s, a number of large industrial complexes had been constructed as a part of industrialization plan in Korea. Accordingly, the forest exosystems around them has been under chronic influences of air pollution and effects of air pollution on plants became a matter of concern. In Yocheon Industrial Complex which consisted of lots of petrochemical plants and a phosphatic fertilizer manufacturing plant, forests has been exposed to chronic air pollution, mainly HF and $SO_2$ gas, Various reports were available to investigate the potential effects of air pollution on crops and forest trees in Yocheon. Kim and Kim surveyed vegetation by naked eye method and reported 71 families, 150 genera and 158 species were growing within a 2 km from air pollution sources in 1981. Needle injuries on Pinus spp. in the polluted area water reported by Kim, et al. and Kim, et al. Kim, et al. investigated the primary production of Pinus thunbergii forests in the polluted area and verified that growth inhibition of Pinus thunbergii was attributable to air pollution. Thus, previous reports suggested that forest ecosystems around Yocheon Industrial Complex were influenced adversely by air pollution. The objective of this study was to investigate the subtle ecological changes in forest community exposed to chronic air pollution in Yocheon.