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        검색결과 30

        2.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cyanobacterial resting cells, such as akinetes, are important seed cells for cyanobacteria’s early development and bloom. Due to their importance, various methods have been attempted to isolate resting cells present in the sediment. Ludox is a solution mainly used for cell separation in marine sediments, but finding an accurate method for use in freshwater is difficult. This study compared the two most commonly used Ludox methods (direct sediment treatment and sediment distilled water suspension treatment). Furthermore, we proposed a highly efficient method for isolating cyanobacterial resting cells and eDNA amplification from freshwater sediments. Most of the resting cells found in the sediment were akinete to the Nostocale and were similar to those of Dolichospermum, Cylindrospermum, and Aphanizomenon. Twenty times more akinetes were found in the conical tube column using the sediment that had no treatment than in the sample treated by suspending the sediment in distilled water. Akinete separated through Ludox were mainly spread over the upper and lower layers in the column rather than concentrated at a specific depth in the column layer. The mibC, Geo, and 16S rDNA genes were successfully amplified using the sediment directly in the sample. However, the amplification products of all genes were not found in the sample in which the sediment was suspended in distilled water. Therefore, 5 g to 10 g of sediment is used without pretreatment when isolating cyanobacterial resting cells from freshwater sediment. Cell isolation and gene amplification efficiency are high when four times the volume of Ludox is added. The Ludox treatment method presented in this study isolates cyanobacterial resting cells in freshwater sediment, and the same efficiency may not appear in other biotas. Therefore, to apply Ludox to the separation of other biotas, it is necessary to conduct a pre-experiment to determine the sediment pretreatment method and the water layer where the target organism exists.
        4,000원
        3.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        멤브레인 기반의 MBRWG (Membrane Bioreactor for Waste Gas) 처리기술은 폐가스 흐름에 대한 높은 선택성을 바탕으로 효과적인 생물학적 제거를 수행할 수 있다. MBRWG에는 몇 가지 잠재적 이점이 있는데, 이 중 가장 두드러진 점은 기상과 액상이 멤브레인 양쪽으로 명확히 분리되어 액상 내 생물막의 최적제어가 용이하고 이를 통해 효과적인 생분해와 생물막의 활성화를 도모할 수 있다는 것이다. MBRWG 처리기술은 특히 xylene 같은 소수성 독성 기체 성분 제거에 유리한데 이는 소수성 기체의 물질전달속도, 독성 및 제거율이 생물막 인근의 액상흐름 및 수분제어에 민감하게 변화하기 때문이다. MBRWG 처리에 쓰이는 다양한 멤브레인 중에서 PDMS-중공사막(hollow fiber)이 가장 높은 기체 물질 전달을 제공한다고 보고되었다. Capillary 형태도 중공사막형태에 비해 비표면적은 낮지만 비교적 활발한 연구가 진행되고 있다. 소수성 기체성분 제거 외에도 기존 생물학적 폐가스 처리 장치에서 배출된 잔류 기체 혼합물이나 먼지를 제거하기 위한 후단 공정에서 멤브레인 활용을 고려할 수 있다.
        4,000원
        4.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 건조버섯 분말을 이용하여 다양한 가공제품에 혼합 가공하기 위하여 국내에서 소비도 및 인지도가 높은 식용버섯인 느타리, 큰느타리, 노루궁뎅이를 대상으로 로스팅 처리 후 건조분말 버섯시료의 생리활성과 영양 성분의 변화를 알아보기 위하여 실험을 수행하였다. 가정용 멀티오븐(HR)을 이용하여 로스팅 시간별로 생리활성 성분의 변화를 분석한 결과 생버섯(fresh) 시료에 비하여 소거활성과 함량치가 낮아지거나 비슷였으나, 회전드럼식 로스팅(CR) 처리 후 아질산염소거능은 큰느타리와 노루궁뎅이의 로스팅 시료에서 증가하는 것으로 나타났으며, 총 폴리페놀 함량은 노루궁뎅이 로스팅 시료가 생버섯 (fresh) 시료에 비하여 크게 증가하였다. 가정용 멀티 오븐 60분 로스팅 처리(HR60) 및 회전드럼식 로스팅 처리(CR) 후 각 건조시료의 아미노산 성분 분석한 결과, 느타리의 경우 회전드럼식 로스팅 처리로 인하여 감칠맛을 내는 성분과 단맛을 내는 성분이 증가하였고, 반대로 쓴맛을 내는 성분은 생버섯(fresh)에 비하여 감소한 것으로 나타났다. 큰느타리는 감칠맛과 단맛을 내는 성분이 로스팅 처리 후 증가하였으나, 쓴맛을 내는 성분들도 로스팅 처리로 인하여 동시에 증가하는 것으로 나타났다. 노루궁뎅이는 단맛을 내는 성분은 회전드럼식 로스팅(CR) 처리 후 증가하였고 동시에 쓴맛을 내는 성분도 크게 증가하는 것으로 나타났다. 위와 같은 결과로부터 전반적으로 수분함량이 많은 버섯은 초기 건조 후 여분의 수분을 증발시키며 로스팅하는 방법이 가정용 멀티오븐에 비하여 생리활성 성분의 증가에 효과적이었으며 아미노산의 단맛과 감칠맛을 증대시키는 것으로 확인되었다. 향후 더 다양한 식용버섯 및 버섯과 혼합 가능한 첨가물들에 대한 검토가 이루어져야하며, 이들 단독으로 또는 혼합하여 로스팅한 후의 생리활성 및 영양성분의 변화에 대한 연구를 진행하여야 할 것으로 사료된다.
        4,000원
        5.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The amount of waste water generated from the domestic sources is consistently increasing in proportion to economic growth, and the conventional activated sludge process is widely being used for general waste water treatment. But the ministry of environment becomes stringthent treatment standards of N and P (less than 20mg/L of N, 2mg/L of P) to prevent the eutrophication of lake water, and therefore highly advanced treatment technology is required not only in the existing treatment plants where the activated sludge process is being used, but also in newly constructed treatment plants for the treatment of N and P. This study is aimed at highly operating the engineering technology method was developed by domestic to eliminate N and P at the same time. Experiments were conducted in the treatment plant located in Yong In city. The bioreactor was started from the principal equipment for the elimination of N and P and the elimination of organic compounds. It consists of an internal recycle piping from the end of the aerobic tank to the anoxic tank and external recycle piping from the final settling basin to the denitrification tank. By experiment of 4 types separate inflow of waste water to the denitrification tank and the anaerobic tank, and changes in staying time at the anoxic tank and the aerobic tank, the elimination of organic compounds in each type and the relationship in the efficiency between the elimination of N and P were researched.
        4,000원
        6.
        2013.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 TNT 오염토양을 콤포스팅과 슬러리생물상으로 처리 후 형광미생물을 이용하여 독성을 평가하고자 실시되었으며, 운전기간은 각각 45일과 200일이었다. 콤포스팅 처리 후 C/N비 조절용으로 아세톤을 첨가한 경우의 GL값은 40으로 글루코오스를 첨가한 경우(GL 80)보다 낮아 독성이 더 많이 제거되었다. 혐기성, 혐기성/호기성, 그리고 호기성 조건의 슬러리생물상으로 처리 후 GL값은 각각 6, 8, 4로 나타나 독성이 거의 없는 수준까지 크게 감소하였다. GL값과 S. typhimurium 수의 상관도는 1차식으로 표현이 가능하였으며, 생물학적 처리에 따른 미생물독성과 돌연변이성 변화는 비교적 높은 상관도 (r > 0.8890)를 나타내었다.
        4,200원
        7.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We analyzed the viable population changes of Paenibacillus polymyxa E681, a plant growth-promoting rhizobacterium, on seeds and roots after bioformulation at varying time intervals during the storage. The viable population of E681 on tested crop seeds sustained log 4-5 cfu/seed after 300 days of seed treatment. The ability of root colonization and inhibition of fungal mycellial growth was not influenced even after 300 days of seed treatment. The seed-soaking treatment returned better results than powder formulation, in increasing the initial population of E681 on plant roots. Collectively, it was found that E681 is a durable and stable biological control agent for application to crop seeds.
        4,000원
        8.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 영산강유역 농공폐수처리장 방류수중의 유기오염물질 분포를 관찰하였다. 시료채취 지점은 영산강 유역에 존재하는 4지점의 농공단지 폐수처리장을 선정하였다. 본 연구에서 GC-Ion trap MS로 300종의 일반적인 화학물질을 ppt수준에서 검출할 수 있는 방법을 이용하여 분석하였다. 농공폐수처리방류수에서 검출된 주요 유기오염물질은 농약류, CH구조의 방향족, CHO구조의 프탈레이트류, 그리고 CHO(N) 구조의 아로메틱 아민류였다. 또한 diethylphthalate를 포함한 17종의 내분비계장애물질이 검출되었다. XTT assay를 이용한 세포독성 결과는 TV로 나타냈으며, 그들의 세포독성은 A지점에서 27.2, D지점에서 24.4로 가장 높게 나타났다. 한편 화학적 분석 결과와 생물학적 독성도와는 일치하지 않는 것으로 나타났다.
        4,000원
        9.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Based on the experiment results of laboratory scale modified anoxic-oxic process for leachate treatment, biological nitrogen removal program was verified in terms of SS, COD, and TN concentration. These measured water qualities concentration could be predicted by biological nitrogen removal program with R2 of 0.994, 0.987, 0.990, respectively. No error was occurred between water qualities concentration and quite wide range of water qualities concentration (i.e., 50-4200 mg/L) during the modelling. Each unit and final effluent of simulated concentration was kept good relationship with that of measured concentration therefore this biological nitrogen removal program for sewage or wastewater treatment plants has good reliance.
        4,000원
        10.
        1995.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The dewatering characteristics of the sewage sludge was investigated through the experimental observations and model simulations. The activated sludge and the anaerobically digested sludge were examined for the dewaterability evaluation within the pressure range of $0{\sim}10^6N/m^2$. Modified Buchner funnel test and compression test by the consolidometer were conducted to evaluate average specific resistance, porosity, and moisture percentage of filter cake. Shirato's technique of compression-permeability test was followed for the pressure range lower than about $10^2N/m^2$. The flocculation effects on sludge dewatering was also examined for ferric chloride and polymeric flocculant. The application of hydrated lime which can be used for flue-gas desulfurization showed improved moisture percentage, and was thought to have positive feasibility in combined system of sludge dewatering and incineration. Determined characteristic constants were applied to Tiller's cake filtration model to simulate liquid pressure distribution and porosity distribution in cake. Model simulations showed a sharp drop of the porosity close to the cake-medium interface for the highly compressible material such as the activated sludge and the anaerobically digested sludge.
        4,500원
        11.
        1994.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to develop a new RBC process available for the effective removal of organic matters and nitrogen in sewage. The RBC process for the oxidation organic compounds and nitrification was designed to occur at the 1st-stage and next-stage RBC respectively. Then nitrified water was recycled to the denitrifying RBC located at the lower part of the 1st-stage RBC. Some results were summarized as follows. 1. The loading limitation was represented as $60g{\cdot}COD/gm^2/day$ in experiment of simultaneous removal of organic matter and nitrogen. The maxmum COD % removal was 85% at the load $35g{\cdot}COD/m^2/day$. 2. The $NO_3-N$ % removal was approximately 80% at the load $60g{\cdot}COD/m^2/day$ and the maximum $NO_3-N$ remaval rate was $3.9g{\cdot}COD/m^2/day$ and the overall C/N ratio of 11.0 as required to achive 80% of $NO_3-N$% removal. 3.$NO_3-N$ removal rate was rapidly decreased above the load $7g{\cdot}NH_4{^+}-N/m^2/day$ and the maximum $NO_3-N$ removal rate was $3.7g{\cdot}NO_3-N/m^2/day$. 4. Irrespective of the recycle ratio, the COD % removal at the system of 2-stage RBC unit was nearly constant as 89% while the maximum one in the 1st-stage unit was 77% in the case of 50% recycle. 5. The maximum COD % removal in the 3-stage RBC system was 93% while 1st-stage one being 80%, under the $NH_4{^+}-N$ load of $7.4g/m^2{\cdot}d$. Also maximum percentage of nitrification and denitrification was 69% and 41% respectively, under the same $NH_4{^+}-N$ load.
        4,200원
        12.
        2023.07 KCI 등재 서비스 종료(열람 제한)
        In this study, the treatment of livestock wastewater using an aerobic granular sludge based sequencing batch reactor was investigated. The reactor operation was carried out by general injection and split injection methods. The average removal efficiency of organic matter after the adaptation period was 71.5 and 87.4%, respectively. Some untreated organic matter was attributed to recalcitrant organic matter. The average removal efficiency of total nitrogen was 65.6 and 88.4%, respectively. These results indicate that the denitrification reaction by split injection was carried out smoothly. As for the solids, the ratio of aerobic granular sludge/mixed liquor suspended solid can be determined as the main factor of the process operation, and the ratio increased gradually and finally reached 86.0%. Correspondingly, the sludge volume index (SVI) was also improved, reaching 54 mL/g at the end of operation, and it is believed that the application of a short settling time contributed to the improvement of settleability.
        13.
        2016.10 서비스 종료(열람 제한)
        Background : This study was performed to investigate by antioxidant activity, total phenolic contents, total flavonoid contents, and effective component of Astragalus membranaceus treated with different artificial light Sources (fluorescent lamp, red, blue, green, white, LEP). Methods and Results : We investigated the effects of various artificial light sources on the DPPH radical activity, total phenol and flavonoid contents, tyrosinase activity and main flavonoid compounds contents (formononetin and calycosin) and other biological activities in A. membranaceus. Antioxidant activities were 53.6% as the highest level of activity under LEP light. Growth under LEP light also produced the highest total phenolic and flavonoid contents of 36.05 and 5.94 mg/ml, respectively. Extracts from plants grown under LEP light caused the highest inhibition of tyrosinase activity with inhibition of 35.37, 61.87, and 65.49%, respectively, for extract concentrations of 100 μg/ml, 500 μg/ml, and 1000 μg/ml compared with other artificial light treatments. Conclusion : Little information is available on the influence of LED and LEP light sources on antioxidant production or other biological activities in A. membranaceus. Our goal in this study was to determine the effects of LED and LEP artificial light sources on the production of new functional compounds in A. membranaceus.
        14.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        In Korea, many drinking water treatment plants (DWTPs) have introduced and are going to introduce biological activated carbon (BAC) process to treated dissolved organic matter (DOM) in water which are difficult to control by conventional water treatment processes. Even though more decade have passed since introduced BAC in Korea, most of BAC operating method was followed to the modified sand filter operating manuals. In case of BAC backwashing, many DWTPs set the periods of backwashing about 3∼5 days. In this study, we have collected data to set the proper BAC backwashing periods from both pilot-plant and real DWTPs. We had measured heterotrophic plate count (HPC), turbidity, water temperature, dissolved organic carbon (DOC) and headloss from just after backwashing to the next backwashing time for two years. Considering water quality factors, the BAC run time from backwashing to the next backwashing could extend more 30 days without water quality deterioration if the head loss do not reach the limited level which depends on each BAC facilities’ condition. It means the BAC treated water could be saved in the proportion of extended the backwashing period to the existing backwashing period.
        16.
        2014.03 KCI 등재 서비스 종료(열람 제한)
        도계량을 현재의 2배까지 증가시킬 예정인 닭 가공 업체인 A사의 생물학적 처리조를 대상으로 하여 처리효율을 2배까지 높이는 방안을 모색하였다. 이를 위해 MLSS 농도가 증가할 경우 이에 따른 유기물 및 질소 제거 효율 증가에 대한 근거를 확보하고자 연구를 진행하였다. 연구는 닭 가공 폐수를 1차 화학 처리한 가압부상처리수를 대상으로 진행되었으며 SBR 형태로 진행되어 호기조 상태 25시간 운전 후, 무산소조 상태 5시간으로 운전되었다. MLSS 12,700mg/L로 진행된 실험 결과 호기조 상태 25시간 이내에 질산화가 완벽하게 일어났으며 C/N비 3:1 이상 실험군에서의 탈질 효율도 90%를 초과하였다. 후에 진행된 MLSS 농도 대비 유기물 및 질소 제거 효율 비교에서는 MLSS 농도를 5,600에서 12,700mg/L까지 변화시켰으며 MLSS 농도 10,800mg/L 실험군에서 유기물과 총 질소 농도 모두 배출허용기준치를 만족하는 결과를 보였다.
        19.
        2010.03 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to investigate treatment efficiency in dyeing wastewater treatment by the high rate aeration system(HRA) and a combination of the HRA with magnetized wastewater treatment system(MWS). At the hydraulic retention time of 16hr, 24hr, 30hr, BOD removal efficiencies of HRA system were 93%, 96% and 98%, combination of the HRA with MWS system were 94%, 96.8% and 98.2%, respectively. In case of COD, at the hydraulic retention time of 16hr, 24hr, 30hr, COD removal efficiencies of HRA system were 66%, 77.1% and 83.1%, combination of the HRA with MWS system were 70.2%, 80.1% and 86.6%, respectively. The comparison of the HRA and combination of the HRA with MWS, effluent BOD of the former was 22.7mg/ℓ and the latter was 19.4㎎/ℓ, therefore biological treatment efficiency identified to increase by the MWS.
        20.
        2008.05 KCI 등재 서비스 종료(열람 제한)
        The bacterial community structure in biological activated carbon (BAC) process in drinking water treatment plant was investigated by Fluorescent in situ Hybridization (FISH) with rRNA-targeted oligonucleotide probe. Samples were collected at different three points in BAC process every month for one year. They were hybridized with a probe specific for the alpha, beta, gamma subclass of the class Proteobacteria, Cytophaga- Flavobacteria group and Gram-positive high G+C content (HGC) group. Total numbers of bacteria in BAC process counted by 4',6-diamidino-2-phenylindole (DAPI) staining were 5.4×1010 (top), 4.0×1010 (middle) and 2.8×1010 cells/ml (bottom). The number of the culturable bacteria was from 1.0×107 to 3.6×107 cells/ml and the culturability was about 0.05%. The faction of bacteria detectable by FISH with the probe EUB338 was about 83% of DAPI counts. Gamma and alpha subclass of the class Proteobacteria were predominant in BAC process and their ratios were over 20% respectively. In top and middle, alpha, beta and gamma subclass of the class Proteobacteria competed with each other and their percentages was changed according to the season. In bottom, gamma subclass of the class Proteobacteria was predominant all through the year. It could be successfully observed the seasonal distribution of bacterial community in biological activated carbon process using FISH.
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