• 한국환경농학회지
• /
• 제19권5호
• /
• pp.426-432
• /
• 2000

Field experiment was performed from August 1996 to December 1999 to examine the feasibility of constructed wetland system for sewage treatment in rural areas. A pilot system was installed in Konkuk University and the effluent of septic tank for school building was used as an influent to the wetland treatment basin. The system was composed of sand and reed, and operated continuously including winter time. Average removal rate of about 70% was observed for BOD, COD, and SS, about 50% for T-P, and about 25% for T-N. The reason for poor T-N removal might be due to high loading rate and short retention time. The system demonstrated satisfactory effluent concentration and stable performance in growing season. And it also worked adequately in wintertime even below $10^{\circ}C$ without freezing, and removal was still significant. The amount removed in BOD, COD, and SS was almost the same as in the growing season, and the amount removed in nutrients was about half of the one in growing season. Overall performance of the experimental system was compared with existing data base (NADB, 1994), and it was within the range of general system performance. As study period increased, removal rates for BOD, COD, SS, and T-P were consistently maintained and even enhanced, but removal rate for T-N decreased slightly. Wetland system was thought to be a feasible alternative for sewage treatment in rural area considering its low cost and low maintenance requirement. However, the effluent of the experimental wetland system often exceeded current effluent water quality standards, therefore, further treatment could be required if the effluent should be discharged to public waters. Wetland system of interest locates in rural area and is a part of rural ecosystem, therefore, ultimate disposal of reclaimed sewage for agricultural purpose or subsequent land treatment might be available and further research in this matter is recommended.

• 대한화학회지
• /
• 제42권6호
• /
• pp.672-678
• /
• 1998

산업폐기물인 꽃게의 껍질로부터 chitin을 탈아세틸화시켜 분자량이 서로 다른 chitosan을 제조하였다. Rhodamine 6G(Rh 6G)-sodium dodecyl sulfate(SDS)계 및 Rh 6G-chitosan계들의 흡수 및 형과 spectra를 조사하였고, chitosan의 분자량 및 pH에 따른 Rh 6G-SDS-chitosan계의 응집효과에 대해 조사하였다. Rh 6G-SDS계의 흡광도나 형광세기는 S/D(SDS 농도/Rh 6G 농도)=32 이하에서 감소하다가 그 이상에서 다시 증가하였다. 부유물질(SS) 제거율이나 투광도로부터 S/D=32에서 chitosan을 첨가한 Rh 6G-SDS-chitosan계의 응집 성능이 Rh 6G-SDS계에 비해 훨씬 우수함을 알 수 있었다. 그리고 chitosan의 농도나 분자량이 크면 클수록, S/D 첨가 범위는 32에서 100까지 확대되는 것을 알 수 있었다. 부유물질의 제거율은 chitosan의 분자량이 클수록 pH 2∼9에서 우수한 성능을 가지는 반면, pH 12 이상에서 부유물질의 제거율은 현저히 저하되는 것을 알 수 있었다.

• 한국축산시설환경학회지
• /
• 제7권3호
• /
• pp.169-172
• /
• 2001

축산기술연구소 유우사에 있는 계류식 우사에서 홀스타인 착유우 6두를 공시하여 1998년 9월 2일부터 9월 11일까지 10일간 개체별로 계류하여 배합사료를 NRC 사양표준에 기준하여 급여하고 조사료로 옥수수 싸일 레지 및 목건초를 자유채식토록 하여 분뇨배설랑과 특성을 조사하였다. 시험기간중 착유우의 평균체중은 550.0kg 이었으며 평균 사료섭취량은 건물기준 16.7 kg이었다. 산유량은 평균 24.4kg이었으며, 음수량은 85.4l였다. 분뇨배실량은 평균 63.5 kg으로, 분이 42.3, 뇨가 21.2kg이있다. 분뇨의 특성에서 분과 뇨의 수분 함량은 각각 83.9, 96.9%였고, pH는 각각 6.6, 7.6으로 나타났다. 분의 $BOD_5,\;COD_{Mn}$, SS, T-N, T-P는 각각 16,560, 40,329, 78,500, 2,854, 577mg/$\ell$였고, 뇨의 $BOD_5,\;COD_{Mn}$, SS, T-N, T-P는 각각 4.580, 7.575, 370, 4,164, 7mg/l로 나타났다. 분뇨중의 중금속 함량은 상당히 낮은 수준으로 나타났다.

• 한국농공학회논문집
• /
• 제62권6호
• /
• pp.43-50
• /
• 2020

The Doam Lake watershed is one of the non-point source management areas announced by the Ministry of Environment, and is a constant problem for the stream ecosystem dut to Storm water. In this study, a total of 48(rainfall) and 47(non-rainfall) sites were investigated for the entire watershed (Samyangcheon, Chahangcheon, Hoenggyecheon, Yongpyeongcheon, Songcheon, Lake Doam) on August 15, 2019 and on October 18, 2019 to estimate the source of turbid water in the Doam Lake watershed. Subsequently, water quality analysis was performed on Suspended Soild (SS), Turbidity, Total Phosphorus (TP), Total Nitrogen (TN), and Biochemical Oxygen Demands (BOD) and correlation among water quality parameters was analyzed based on the analyzed samples. As a result, most of the turbid water generated during rainfall was in highland fields. During rainfall, Hoengyecheon had the highest average SS concentration among all streams, and during non-rainfall, the average SS concentration was highest in Yongpyeongcheon, so the two stream were selected as vulnerable areas. However, since Yongpyeongcheon may be a temporary phenomenon due to river construction, additional continuous monitoring is required. Therefore, in the Doam Lake watershed, intensive management is required for vulnerable areas.

• Journal of Microbiology and Biotechnology
• /
• 제31권3호
• /
• pp.439-446
• /
• 2021

Quercus infectoria (nutgall) has been reported to possess antimicrobial activities against a wide range of pathogens. Nevertheless, the biofilm removal effect of nutgall extract has not been widely investigated. In this study, we therefore evaluated the effect of nutgall extract in combination with cetrimonium bromide (CTAB) against preformed biofilm of Salmonella Typhimurium on polypropylene (PP) and stainless steel (SS) coupons in comparison with other sanitizers. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of nutgall extract and surfactants (CTAB and sodium dodecyl sulfate; SDS) were assessed. CTAB showed a more efficient antimicrobial activity than SDS and was selected to use in combination with nutgall extract for removing biofilm. To determine the biofilm removal efficacy, the PP and SS coupons were individually submerged in 2x MBC of nutgall extract (256 mg/ml) + 2x MBC of CTAB (2.5 mg/ml), nutgall extract alone (256 mg/ml), CTAB alone (2.5 mg/ml), distilled water, and 100 ppm sodium hypochlorite for 5, 15, and 30 min. The remaining sessile cells in biofilm were determined. Overall, the greatest biofilm removal efficacy was observed with nutgall extract + CTAB; the biofilm removal efficacy of sanitizers tended to increase with the exposure time. The SEM analysis demonstrated that S. Typhimurium biofilm on PP and SS coupons after exposure to nutgall extract + CTAB for 30 min displayed morphological alterations with wrinkles. This study suggests nutgall extract + CTAB may be an alternative to commonly used sanitizers to remove biofilm from food contact surfaces in the food industry and household.

• The Korean Journal of Physiology and Pharmacology
• /
• 제23권4호
• /
• pp.231-236
• /
• 2019

In drug discovery or preclinical stages of development, potency parameters such as $IC_{50}$, $K_i$, or $K_d$ in vitro have been routinely used to predict the parameters of efficacious exposure (AUC, $C_{min}$, etc.) in humans. However, to our knowledge, the fundamental assumption that the potency in vitro is correlated with the efficacious concentration in vivo in humans has not been investigated extensively. Thus, the present review examined this assumption by comparing a wide range of published pharmacokinetic (PK) and potency data. If the drug potency in vitro and its in vivo effectiveness in humans are well correlated, the steady-state average unbound concentrations in humans [$C_{u_-ss.avg}=f_u{\cdot}F{\cdot}Dose/(CL{\cdot}{\tau})=f_u{\cdot}AUCss/{\tau}$] after treatment with approved dosage regimens should be higher than, or at least comparable to, the potency parameters assessed in vitro. We reviewed the ratios of $C_{u_-ss.avg}$/potency in vitro for a total of 54 drug entities (13 major therapeutic classes) using the dosage, PK, and in vitro potency reported in the published literature. For 54 drugs, the $C_{u_-ss.avg}$/in vitro potency ratios were < 1 for 38 (69%) and < 0.1 for 22 (34%) drugs. When the ratios were plotted against $f_u$ (unbound fraction), "ratio < 1" was predominant for drugs with high protein binding (90% of drugs with $f_u{\leq}5%$; i.e., 28 of 31 drugs). Thus, predicting the in vivo efficacious unbound concentrations in humans using only in vitro potency data and $f_u$ should be avoided, especially for molecules with high protein binding.

• Journal of Advanced Marine Engineering and Technology
• /
• 제13권2호
• /
• pp.43-63
• /
• 1989

Various kinds of corrosion prevention methods have been developed. It is known that the method of electrochemical protection is more effective and economical than any other method on the large scale metal structures in corrosive solutions. Strong acid solutions such as nitric and sulfuric acid solutions are often used in industries, and the expensive stainless steel is almost exclusively used for the equipment that comes in contact with such acid solutions. However, it is more reasonable that carbon steel is used rather than stainless steel depending upon concentration of those acid solutions from the economical viewpoint. In this study, the typical strong acid solution such as nitric and sulfuric acid solutions are chosen for the experiment and the selected materials of specimen are the stainless steels of SUS 304L and SUS 316L, the carbon steels of SS 41, SM 50 and RA 32, and highly pure lead. Electrochemical protection diagrams can be drawn with data from the external cathodic and anodic polarization curves of SUS 304L, SUS 316L and SM 50 steels in 5-60% nitric acid solutions and from those polarization curves of SS 41, RA 32, SM 50 and SUS 316L steels, and highly pure lead in 2.5-98% sulfuric acid solutions at the slow scanning rate. The data obtained with using the determination method of the optimum cathodic protection potential, the Tafel extrapolation method and the characteristics of anodic polarization curves. The main results obtained from the diagrams are as follows: 1) In nitric acid solution : (1) Corrosion potentials exist in each of those corrosion zones on the stainless steels in the lower concentration than about 12% solutions and on the high tensile strength steels in the lower concentration than about 30% solutions, but the corrosion current (density) in each zone is small on the above mentioned former steels and large on the latter ones. (2) The stainless steels can be self-passivated in the higher concentration than 15% solutions, and the high tensile strength steels gives rise to the same phenomenon in the higher concentration than 35% solutions. (3) The stainless steels in the lower concentration than 60% solutions and the high tensile strength steels in the higher concentration than 35% solutions can be used without protection, but the latter steels must ve protected anodically in the lower conccentration than about 30% solutions. 2) In sufuric acid solution : (1) The carbon steels can be self-passivated in the higher concentration than 45% solutions, and the SUS 316L steel in higher concentration than 75% solutions and the lead in all concentration solutions also gives rise to the same phenomenon. (2) The lead in the lower concentration than 80% solutions and the SUS 316L steel in the higher concentration than 80% solutions can be used without protection. (3) The carbon steels in the higher concentration than 50% solutions also can be used without protecting economically, but the SUS 316L steel in the 20-70% solutions are considerably corrosive without protecting anodically.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2004년도 Proceedings of the 4th Korea-China Joint Workshop on Nuclear Waste Management
• /
• pp.12-27
• /
• 2004

Pretreatment process consisted of submerged hollow-fiber microfiltration(HMF) membrane and spiral-wound nanofiltration(SNF) membrane has been developed by NETEC, KHNP for the purpose of improving the impurities of liquid radioactive waste before entering Selective Ion Exchange System(SIES). The lab-scale combined system was installed at Kori NPP #2 nuclear power plant and demonstration tests using actual liquid radioactive waste were carried out to verify the performance of the combined system. The submerged HMF membrane was adopted for removal of suspended solid in liquid radioactive waste and the SNF membrane was used for removal of particulate radioisotope such as, Ag-l10m and oily waste because ion exchange resin can not remove particulate radioisotopes. The liquid waste in Waste Holdup Tank (WHT) was processed with HMF and SNF membrane, and SIES. The initial SS concentration and total activity of actual waste were 38,000ppb and $1.534{\times}10_{-3}{\mu}Ci/cc$, respectively. The SS concentration and total activity of permeate were 30ppb and lower than LLD(Lower Limit of Detection), respectively.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
• /
• pp.82-85
• /
• 2006

The Geostationary Ocean Color Imager (GOCI) will be loaded in Communication, Ocean and Meteorological Satellite (COMS). To efficiently apply the GOCI data in the variety of fields, it is essential to develop the standard algorithm for estimating the concentration of ocean environmental components (, , and ). For developing the empirical algorithm, about 300 water samples and in situ measurements were collected from sea water around the Korean peninsula from 1998 to 2006. Two kinds of chlorophyll algorithms are developed by using statistical regression and fluorescence technique considering the bio-optical properties in Case-II waters. The single band algorithm for is derived by relationship between Rrs (555) and in situ concentration. The CDOM is estimated by absorption coefficient and ratio of Rrs(412)/Rrs(555). These standard algorithms will be programmed as a module of GOCI Data Processing System (GDPS) until 2008.

• 한국환경과학회지
• /
• 제20권9호
• /
• pp.1115-1124
• /
• 2011

There is an increasing incidence in health problems related to environmental issues that originate from inadequate treatment of sewage. This has compelled scientists to engage in innovative technologies to achieve a effective disinfection process. Electrolysis has emerged as one of the more feasible alternatives to conventional disinfection process. The objectives of the present paper were to investigate the effect of chemical characteristics on oxidant formation and Escherichia coli (E. coli) disinfection in synthetic sewage effluents. The influence of parameters such as COD, SS, T-N and T-P were investigated using laboratory scale batch reactor. The results showed that the higher COD, T-N and T-P concentration, the lower N, N-Dimethyl-4-nitrosoaniline (RNO, indicator of the generation of OH radical) degradation and E. coli disinfection was observed. The order of effect of RNO degradation and E. coli disinfection was T-P > COD > T-N > SS. When 4 parameter of water quality were worked simultaneously, oxidants formation and disinfection was decreased with increase of the concentration of sewage. To increase of the disinfection performance, the increase of disinfection time or electric power was need.