• 상하수도학회지
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• 제11권2호
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• pp.112-127
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• 1997

The purpose of this study is to get optimum operating factors of Upflow Anaerobic Sludge Blanket (UASB) reactor by introducing methods that make it to reduce inhibition possible in each process wastewater treatment. The used substrates, concentrated corn starch liquid (CSL) wastewater, modified starch, filtering and decoloring wastewater, ion refining wastewater, and mixed wastewater including modified starch and not including modified starch, are generated from molasses process. The seeding sludge is the digested sludge that had been applied to molasses wastewater. Batch test to reduce the inhibition factors that might be existed in each wastewater was examined. Based on the this test, the optimum operating factors according to alkalinity and pH variation was studied through the continuous test using three 5.5 L UASB reactor. The first reactor added $NaHCO_3$ to control alkalinity. The hydraulic retention time (HRT) reduced to 8 hours and the organic loading rate increased gradually. The second reactor changed the pH of influent from 7.0 to 6.0 using NaOH. The third reactor was operated without changes to compare the above two reactors. As the result, the inhibition in concentrated CSL wastewater was removed by adding iron (II). When trace metals were added to mixed wastewater not including modified starch, the digestability by gas production rate increased to more fifty percentage than mixed wastewater that was not adding the trace metals. The reason that the inhibition did not decreased in spite of adding trace metals and nutrients was influenced by high concentration generated during the acid fermentation. The UASB reactors using the mixed wastewater with the most effective performance were operated as 500 mg/L as $CaCO_3$ alkalinity and 6.0 pH at steady state, and at this time, the gas production rates were 283 and 311mL gas/g $COD_{added}$. The COD removal rates were 84.7 and 86.3%, respectively.

• 유기물자원화
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• 제3권2호
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• pp.37-45
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• 1995

유가공폐수 처리를 위한 UASB 의 성능과 운전상의 문제점을 조사하였다. 인공 유가공폐수는 부하3.9kg $COD/m^3.day$까지 성공적으로 운전이 가능하였으며, 이 때 90% 이상의 COD 제거율과 단위 체적당 1.23 I/I.day 의 가스가 발생하였다. 그러나, 부하 2.1kg $COD/m^3.day$ 에서는 침전부 표변에 스컴층이 형성되면서 슬러지부상과 유실이 관찰되었다. 혈청병 (SBT) 실험으로 측정된 우유공장 실폐수와 아이스크림폐수의 생화학적 메탄생성능(BMP) 은 각각 0.135, 0.66ml $CH_4/mg\;COD_{added}$이었다. 반응조의 슬러지 활성도는 식종 초기에 0.159g $COD-CH_4/g$ VSS.d 에서 운전 90 일이 경과하는 동안에 8배 이상 증가하였다.

• 한국환경과학회지
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• 제21권12호
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• pp.1495-1501
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• 2012

In this study, an experiment was conducted on influent water with low concentrations of organic matter, such as river water or secondary treatment water of a sewage treatment plant, according to HRT changes by using aerobic biofilm. In the biofilm process, as the biofilm increases in thickness, the inner membrane can be low in oxygen transfer rate and become anaerobic conditions, while the detachment of biomass from biofilm occurs. To overcome these limitations in the detachment of microorganisms in biofilm, the yarn, which was made from poly propylene(PP), was weaved and manufactured into a tube. Then, a test was carried out by injecting air so that the interior of the biofilm could create aerobic conditions. The results of the experiment showed that the removal efficiency of $TCOD_{cr}$ reached 66.1~81.2% by HRT 2hr, and 50.9 ~61.8% after HRT 1 hr. The removal efficiency of $SCOD_{cr}$ was 45.9 to 55.1% by HRT 1hr, and 26.1% in HRT 0.5hr, showing the highest removal efficiency in HRT 1hr. The SS removal efficiency was at 81.8 to 94.6%, and the effluent SS concentration was very low, indicating less than 2.2 mg/L in all HRT's. As a result, the $SCOD_{cr}$ and $NH_4{^+}$-N that were removed per specific surface area and attached to microbial biofilm showed the highest efficiency in HRT 1hr with 8.37 $gSCOD_{cr}/m^2{\cdot}d$, 2.93 $gNH_4{^+}-N/m^2{\cdot}d$. From the result of reviewing the characteristics of biofilm growth, microorganisms were found to be attached, and increased by 36 days. Later, they decreased in number through detachment, but showed a tendency to increase again 41 days later due to microbial reproduction.

• Biomolecules & Therapeutics
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• 제15권4호
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• pp.261-265
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• 2007

Hydroxyproline (HYP) is a post-translational product of proline hydroxylation catalyzed by an enzyme prolyl 4-hydroxylase (P4H) which plays a crucial role in the synthesis of all collagens. Considering the role of collagen and its significance in many clinically important diseases such as liver fibrosis, a great deal of attention has been directed toward the development of an assay at cell-based system. The reason is that cell-based assay system is more efficient than enzyme-based in vitro system and takes much less time than in vivo system. Several assay procedures developed for P4H are laborious, time-consuming and not feasible for the massive-screening. Here, we report the cell-based assay method of prolyl 4-hydroxylase in immortalized rat hepatic stellate HSC-T6 cells. To optimize the cell culture condition to assay for HYP content, various concentrations of reagents were treated for different times in HSC-T6 cells. Our data showed that the treatment with ascorbate in a hypoxic condition for 24 h resulted in the maximal increase of HYP by 1.8 fold. Alternatively, cobalt chloride ($5\;{\mu}M$) and ascorbate ($50\;{\mu}M$) in normoxic states exhibited similar effect on the production of HYP as in a hypoxic condition. Therefore, cobalt chloride can be substituted for a hypoxic condition when an anaerobic chamber is not available. Rosiglitazone and HOE077, known as inhibitors of collagen, synthesis decreased P4H enzyme activity by 32.3% and 15%, respectively, which coincided with previous reports from liver tissues. The level of the smooth muscle ${\alpha}$-actin, a marker of activated stellate cells, was significantly increased under hypoxia, suggesting that our experimental condition could work for screening the anti-fibrotic compounds. The assay procedure took only 3 days after treatment with agents, while assays from the primary stellate cells or liver tissues have taken several weeks. Considering the time and expenses, this assay method could be useful to screen the compounds for the inhibitor of prolyl 4-hydroxylase.

• 상하수도학회지
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• 제19권6호
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• pp.791-799
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• 2005

The phased isolation intra-clarifier ditch system used in this study is a simplified novel process enhancing simultaneous removal of biological nitrogen and phosphorus in municipal wastewater in terms of elimination of additional pre-anaerobic reactor, external clarifier, recycle of sludge, and nitrified effluent recirculation by employing intrachannel clarifier. Laboratory-scale phased isolation ditch system was used to assess the treatability on municipal wastewater. When the system was operated at the HRTs of 6~12hours, SRTs of 9~31days, and cycle times of 2~8hours, the system showed removals of BOD, TN, and TP as high as 88~97%, 70~84%, and 65~90%, respectively. The rainfall in Korea is generally concentrated in summer because of site-specific characteristics. Especially, the wet season has set in on June to August. In combined sewers, seasonal variations are primarily a function of the amount of stormwater that enters the system. In order to investigate the effect of hydraulic shock loading on system performance, the laboratory-scale system was operated at an HRT of 6hours (two times of influent flowrate) during two cycles (8hours). The system performance slightly decreased by increasing of influent flowrate and decreasing of system HRT. Nitrification efficiency and TN removal were slightly decreased by increasing of influent flowrate (decreasing of system HRT), whereas, the denitrification was not affected by hydraulic shock loading. However, the higher system performance could be achieved again after four cycles. Thus, the phased isolation technology for enhanced biological nutrient removal in medium- and small-scale wastewater treatment plants suffering fluctuation of influent quality and flowrate.

• 한국환경보건학회지
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• 제18권2호
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• pp.67-74
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• 1992

The lab-scale biological A$_{2}$O system was applied from treating piggery wastewater highly polluted organic material which nitrogen and phosphorous are much contained relatively in conversion with other wastewater. The objective of this study was to investigate the effect of variance parameters on the treatability of this system according to operation conditions. An obtained experimental data were analysed by using principal component analysis (PCA) method. The results are summarized as follows: 1. From Varimax rotated factor loading in raw wastewater, variance of factor 1 was 36.8% and cumulative percentage of variance from factor 1 to factor 4 was 81.5% and of these was related to BOD, TKN and BOD loading. 2. In anaerobic process, variance of factor 1 was 33.5% and cumulative percentage of variance from factor I to factor 4 was 81.8% and of these was related to PO$_{4}$-P, BOD, DO and Temperature. 3. In anoxic process, variance of factor 1 was 30.1% and cumulative percentage of variance from factor i to factor 4 was 84.3% and of these was related to pH, DO, TKN and temperature. 4. In aerobic process, variance of factor 1 was 43.8% and cumulative percentage of variance from factor 1 to factor 4 was 81.5% and of these was highly related to DO, PO$_{4}$-P and BOD. 5. It was better to be operated below 0.30 kg/kg$\cdot$day F/M ratio to keep over 90% of BOD and SS, 80% of TKN, and 60% of PO$_{4}$-P in treatment efficiencies. 6. Treatment efficiencies was over 93% of BOD and SS, 81% of TKN and 60% of PO$_{4}$-P at over 20$^{\circ}$C, respectively.

• Asian-Australasian Journal of Animal Sciences
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• 제21권11호
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• pp.1659-1664
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• 2008

To study the working mechanisms for non-starch polysaccharidases to improve the growth performance of broiler chickens, a 21-day feeding trial was conducted. Two dietary treatments were included: 1) wheat diet (the control); 2) wheat+xylanase diet (xylanase, Allzyme PT, Alltech, Kentucky, USA). There were 8 replicates with 8 birds each for each treatment and the experimental diets were given to birds from hatch. Feed intake and body weight were measured on days 7 and 21. At the same ages, samples were taken for the determination of selected groups of luminal and mucosa-associated bacteria, mucosal morphology, brush-border membrane (BBM) bound enzyme activity and ileal nutrient digestibility. The xylanase supplement increased (p<0.05) body weight gain (BWG) and improved feed conversion ratio (FCR) at the end of the experiment but protein and starch digestibilities were not affected (p>0.05) by xylanase. Up to day 7, xylanase increased the counts of C. perfringens in the ileum and total anaerobic bacteria (TAB) in the caeca (p<0.05, p=0.07, respectively). By day 21, the counts of ileal lactobacilli (p<0.05) and TAB (p=0.07) were lower in birds given the xylanase-supplemented diet than in those on the control diet. No significant differences were observed in the counts of mucosa-associated lactobacilli and coliforms between xylanase treatment and the control at both ages. Villus height at the jejunum was not affected (p>0.05) by the supplement but crypt depth at the same site was reduced at day 7. Also, xylanase tended to increase the concentration of BBM protein (p = 0.09) and the specific activity of sucrase (p = 0.07) at day 21.

• Asian-Australasian Journal of Animal Sciences
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• 제28권6호
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• pp.816-826
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• 2015

The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR). The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted to 400 g/kg (low moisture level, LML), 450 g/kg (medium moisture level, MML), and 500 g/kg (high moisture level, HML), and both non-fermented and 56-d-fermented TMR were subjected to air exposure to determine aerobic stability. Aerobic deterioration resulted in high losses of nutritional components and largely reduced dry matter digestibility. Non-fermented TMR deteriorated during 48 h of air exposure and the HML treatment was more aerobically unstable. On dry matter (DM) basis, yeast populations significantly increased from $10^7$ to $10^{10}cfu/g$ during air exposure, and Candida ethanolica was the predominant species during deterioration in non-fermented TMR. Fermented TMR exhibited considerable resistance to aerobic deterioration. Spoilage was only observed in the HML treatment and its yeast population increased dramatically to $10^9cfu/g$ DM when air exposure progressed to 30 d. Zygosaccharomyces bailii was the sole yeast species isolated when spoilage occurred. These results confirmed that non-fermented and fermented TMR with a HML are more prone to spoilage, and fermented TMR has considerable resistance to aerobic deterioration. Yeasts can trigger aerobic deterioration in both non-fermented and fermented TMR. C. ethanolica may be involved in the spoilage of non-fermented TMR and the vigorous growth of Z. bailii can initiate aerobic deterioration in fermented TMR.

• 대한환경공학회지
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• 제37권4호
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• pp.228-233
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• 2015

본 연구에서는 회분식 실험 및 $A^2/O$ 공법의 연속식 실험으로 아연이 생분해, 산소 소모율, 질산화 및 탈질에 미치는 영향을 검토하였다. 본 연구의 결과를 요약하면 다음과 같다. 아연 영향 실험 결과 유기물 분해는 회분식 실험의 경우 아연 농도 12 mg/L까지 영향을 미치지 않았으며, 연속식 실험의 경우 아연 농도 3.0 mg/L 이상일 때 생분해성이 낮아졌다. 질산화 및 질소 제거의 경우 회분식은 아연 농도 6.0 mg/L 이상일 때 질산화율이 낮아졌으며, 연속식의 경우 아연 농도 3.0 mg/L 이상일 때는 질소 제거율이 낮아졌다. 인 제거의 경우 회분식은 아연 농도 6.0 mg/L, 연속식은 아연 농도 3.0 mg/L 이상일때 인 제거율이 낮아지는 것으로 나타났다. 산소 소모율의 경우 연속식의 아연 농도가 3.0 mg/L 이상이면 미생물 활성에 영향을 주어 산소 소모율이 낮아졌다.

• 유기물자원화
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• 제21권2호
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• pp.71-78
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• 2013

하수처리 탈수여액 내에 존재하는 고농도 인을 스트루바이트 생성을 통해 제거하기 위한 타당성 조사를 수행하였다. 혐기 소화를 거친 탈수여액 내에는 암모니아가 인산염 보다 높은 농도로 존재하므로 별도의 질소 투입 없이 마그네슘 주입과 pH 조절만을 통해 인 제거가 가능하였다. 인 제거 효율은 마그네슘 주입량, 교반 시간, 침전 시간, pH에 영향을 받았으며, 최적 반응 조건은 $Mg^{2+}/PO_4^{3-}$ 비 2 mol/mol 이상, 교반 시간 10분 이상, 침전 시간 120분 이상, pH 8.5 이상으로 도출되었다. 위 조건에서의 연속 운전 시 총인 제거율 80%, 인산염 제거율 82% 달성이 가능하였다. 침전물의 원소 조성과 결정 구조는 기존 보고된 스트루바이트와 유사하였다.