• 상하수도학회지
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• 제11권4호
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• pp.110-117
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• 1997

Performances of combined adsorption and coagulation were evaluated as one of the options for pre-treatment or post-treatment of MSW landfills leachate and industrial landfill leachate. The COD and color removals of leachate from an old MSW landfill were 35% and 33% at an alum dose of 300mg/L with preceding PAC(powdered activated carbon) dose of 200mg/L, respectively. The COD and color removals of leachate from an young MSW landfill were 58% and 25% at an alum dose of 700mg/L and PAC dose of 500mg/L, respectively. The COD and color of biologically treated leachate from an industrial waste landfill were removed up to 32% and 68%, respectively, with pH control at addition of 500mgAlum/L and 1,000mgPAC/L. Adsorption and coagulation process with pH control showed better COD and color removals than the process without pH control for biologically treated leachate from an industrial waste landfill. The color removal was influenced greatly by pH control, while COD removal was not significant. No difference in removal efficiency was observed between adsorption-coagulation and coagulation-adsorption process. The COD removal was accomplished mainly by adsorption, while coagulation was a key mechanism of color removal. However, the mechanism of COD removal was obscure, when BOD/COD ratio was high. Maximum net increases in COD and color removals by the adsorption-coagulation process were respectively 45% and 46% compared with the unit process of adsorption or coagulation, although those removals depended on leachate characteristics. Thus, adsorption-coagulation process was considered to be effective for pre- and post-treatment of landfill leachate, and has distinct features of simple, flexible, stable and reliable operation against fluctuation leachate quality and flowrate.

• 대한한방부인과학회지
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• 제19권1호
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• pp.139-154
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• 2006

Objective : This experimental study was carried out to investigate anti-coagulation effects and mechanism of Hongdeung-tang on the dissentimenated intravascular coagulation Methods : Each 10 rats were classified as normal gorup, control group and treated group. The control group was given a 0.5mg/ml endotoxin intra-vein injection and was occurred Disseminated Intravascular Coagulation(DIC). The treated group were orally administrated 1ml Hongdeung-tang concentration once a day for 6 days and then it was treated the same as the control group. We took the blood from heart and were investigated number of Platelet and white blood cell(WBC), fibrinogen concentration, prothrombin time(PT), activated partial thromboplastin time(APTT), interleukin-6(IL-6), Tumor Necrosis $Factor-{\alpha}(TNF-{\alpha})$, Prostaglandin $E2(PGE_2)$ from them. Results : There were a statistically significant increase of platelet and fibrinogen concentration in the treated group compared to the treated group. The PT was a significantly reduced in treated group compared to the control group. There was no significant change in numbers of WBC and APTT between control and treated group. On the contrary, the number of PT, IL-6, $TNF-{\alpha}$, $PGE_2$ were significantly decreased in treated group compared to the control group. Conclusion : DIC which was occurred by endotoxin intravenous injection seems to related to the increase of IL-6, $TNF-{\alpha}$, $PGE_2$ and Hongdeung-tang has an effect that supress those factors. we can assume Hongdeung-tang has an anti-coagulation effect by those supressing effect.

• 상하수도학회지
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• 제31권1호
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• pp.103-114
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• 2017

A membrane bioreactor by sequentially alternating the inflow and by applying a two-stage coagulation control based on pre-coagulation was evaluated in terms of phosphorus removal efficiency and cost-savings. The MBR consisted of two identical alternative reaction tanks, followed by aerobic, anoxic and membrane tanks, where the wastewater and the internal return sludge alternatively flowed into each alternative reaction tank at every 2 hours. In the batch-operated alternative reaction tank, the initial concentration of nitrate rapidly decreased from 2.3 to 0.4 mg/L for only 20 minutes after stopping the inflow, followed by substantial release of phosphorus up to 4 mg/L under anaerobic condition. Jar test showed that the minimum alum doses to reduce the initial $PO_4$-P below 0.2 mg/L were 2 and 9 mol-Al/mol-P in the wastewater and the activated sludge from the membrane tank, respectively. It implies that a pre-coagulation in influent is more cost-efficient for phosphorus removal than the coagulation in the bioreactor. On the result of NUR test, there were little difference in terms of denitrification rate and contents of readily biodegradable COD between raw wastewater and pre-coagulated wastewater. When adding alum into the aerobic tank, alum doses above 26 mg/L as $Al_2O_3$ caused inhibitory effects on ammonia oxidation. Using the two-stage coagulation control based on pre-coagulation, the P concentration in the MBR effluent was kept below 0.2 mg/L with the alum of 2.7 mg/L as $Al_2O_3$, which was much lower than 5.1~7.4 mg/L as $Al_2O_3$ required for typical wastewater treatment plants. During the long-term operation of MBR, there was no change of the TMP increase rate before and after alum addition.

• 한국환경보건학회지
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• 제38권2호
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• pp.128-135
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• 2012

Objectives: This study was aimed at determining the optimum coagulation dosage in a high turbid kaolin water sample using streaming current detection (SCD) as an alternative to the jar test. Methods: SCD is able to optimize coagulant dosing by titration of negatively charged particles. Kaolin particles were used to mimic highly turbid water ranging from 50 to 600 NTU, and polyaluminum chloride (PAC, 17%) was applied as a titrant and coagulant. The coagulation consisted of rapid stirring (5 min at 140 rpm), reduced stirring (20 min at 70 rpm), and settling (60 min). To confirm the coagulation effect, a jar test was also compared with the SCD titration results. Results: SCD titration of kaolin water samples showed that the dose of PAC increased as the pH rose. However, supernatant turbidity less than 1 NTU after coagulation was not achieved for high turbid water by SCD titration. Instead, a conversion factor was used to calculate the optimum PAC dosage for high turbid water by correlating a jar test result with that from an SCD titration. Using this approach, we were able to successfully achieve less than 1 NTU in treated water. Conclusions: For high turbid water influent in a water treatment plant, particularly during summer, the application of SCD control by applying a conversion factor can be more useful than a jar test due to the rapid calculation of coagulation dosage. Also, the interpolation of converted PAC dose could successfully achieve turbidity in the treated water of less than 1 NTU. This result indicates that an SCD system can be effectively used in a water treatment plant even for high turbid water during the rainy season.

• Environmental Engineering Research
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• 제20권3호
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• pp.223-229
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• 2015

The application of coagulation for feed water pretreatment prior to microfiltration (MF) process has been widely adopted to alleviate fouling due to particles and organic matters in feed water. However, the efficiency of coagulation pretreatment for MF is sensitive to its operation conditions such as pH and coagulant dose. Moreover, the optimum coagulation condition for MF process is different from that for rapid sand filtration in conventional drinking water treatment. In this study, the use of response surface methodology (RSM) was attempted to determine coagulation conditions optimized for pretreatment of MF. The center-united experimental design was used to quantify the effects of coagulant dose and pH on the control of fouling control as well as the removal organic matters. A MF membrane (SDI Samsung, Korea) made of polyvinylidene fluoride (PVDF) was used for the filtration experiments. Poly aluminum chloride (PAC) was used as the coagulant and a series of jar tests were conducted under various conditions. The flux was $90L/m^2-h$ and the fouling rate were calculated in each condition. As a result of this study, an empirical model was derived to explore the optimized conditions for coagulant dose and pH for minimization of the fouling rate. This model also allowed the prediction of the efficiency of the coagulation efficiency. The experimental results were in good agreement with the predictions, suggesting that RSM has potential as a practical method for modeling the coagulation pretreatment for MF.

• 대한한방부인과학회지
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• 제21권1호
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• pp.55-82
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• 2008

Purpose: In this study, we evaluated anti-inflammatory activity and anti-thrombosis effect of Manbunbang(MBB) prescribed to chronic PID patients. Methods: We studied inhibitory effect of platelet aggregation, suppression effect of GPIIb/IIIa activity and inhibitory effect of $TXB_2$ and $PGE_2$ biosynthesis which were caused by ADP, epinephrine, collagen and arachidonic acid in vitro. And suppression of pulmonary embolism, changes of related factors in dextran coagulation condition model and anti-oxidative effect of oxidative damage were studied in vivo. Results: MBB extract showed LD50 of $200\;{\mu}g/ml$ or higher in mouse lung fibroblast cells, and significantly decreased the GPT and GPT level in dextran coagulation condition model compared to the control. MBB extract showed dose-dependent inhibition effect on platelet coagulation induced by ADP, epinephrine, collagen, arachidonic acid. MBB extract showed dose-dependent inhibition effect on GPIIb/IIIa activities compared to the control. MBB extract significantly suppressed TXB2 and PGE2 biosynthesis compared to the control. MBB extract suppressed pulmonary embolism triggered by collagen and epinephrine by 37.5% compared to the control. MBB extract significantly suppressed the decrease of speed of bloodstream caused by blood coagulation in dextran coagulation condition model compared to the control. Concluson : The results strongly suggest the anti-inflammatory activity of Manbunbang through anti-thrombus. Various applications using Manbunbang on inflammatory diseases are anticipated. Anti-oxidative efficacy comparison data between the Manbunbang prescription and the drug compositions may be used as important clinical information, and further investigation of anti-oxidative activities of Chrysanthemum indicum and Rhemaniae Radix should be followed.

• 상하수도학회지
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• 제21권6호
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• pp.653-661
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• 2007

The Disinfectants/Disinfection By-products (D/DBP) Rule proposed by the US Environmental Protection Agency requires the implementation of enhanced coagulation as a control strategy for natural organic matter (NOM) removal and as a means of limiting the formation of all DBPs, i.e., not just the trihalomethanes and haloacetica acids. To control DBP formation, several best available technologies (BATs) were determined for removal of DBPs and DBP precursors. The enhanced coagulation is one of the BATs for DBP precursors removal. Treatment facilities that achieve a specified percent removal of total organic carbon (TOC) prior to the application of a continuous disinfectant or that achieve a residual TOC concentration < 2mg/L prior to the application of a continuous disinfectant are considered to be in compliance with enhanced coagulation. The enhanced coagulation was applied to raw water in Korea, the Han River. Raw water were examined and effects of different raw water qualities on enhanced coagulation were investigated. Three analyses were used for raw water characteristics, water quality measurement, molecular weight distributions, hydrophobic/hydrophilic fractionation. The Han River had the relatively low alkalinity and low organic carbon concentration. The results of molecular weight distributions showed significant portions of low molecular weight organics, which is very different from most water in USA. The alum doses for the required TOC removal guided from USEPA manual were quite low (i.e. 10~30 mg/L alum) for the water, probably due to the specific water quality of the Han River.

• 한국물환경학회지
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• 제28권2호
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• pp.300-304
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• 2012

It has a limitation to satisfy the phosphorus effluent criteria of 0.2 mg/L which will be reinforced from 2012 with the Biological Nutrient Removal (BNR) process. The chemical coagulation process has been operated in parallel with the biological treatment process for advanced treatment of phosphorous in the developed countries including Europe. However, the coagulation process has some disadvantages such as the desired goal may not be achieved without injecting the optimum dosage of the coagulant. This study developed the automatic control system to inject the optimum dosage of phosphorous coagulant into the coagulation process. The adopted coagulant was 10% Poly Aluminum Chloride (PAC) in this study. The automatic control system developed in this study was adopted for the treatment of the phosphorus from the effluent in SBR process. The automatic control system was composed of the data receiving part, the optimum coagulant dosage control part and the data transmit part. The result of the phosphorous advanced treatment of the SBR effluent using the automatic control system showed the removing efficiency over 95% consistently with the phosphorous concentration under 0.02 ~ 0.15 mg/L. The reproducibility analysis for checking the safety of automatic control system showed more than 95% correlation.

• 한국분무공학회지
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• 제11권2호
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• pp.98-104
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• 2006

A charged droplet scrubber was introduced to remove visible smokes generated in many industrial facilities. Lab-scale and field tests were conducted in this study. The system consists of a corona discharger to effectively charge the fine particles, fellowed by an electrostatic chamber to promote coagulation between charged fine particles and oppositely charged droplets and a demister to remove resultant particles. Overall collection efficiency, 98.4% was obtained from a lab-scale test, when a high voltage was applied to an ionizer and a charged droplet scrubber. Field tests also show the high collection efficiencies, 93.5% with one stage and 99.4% with two stage system. This system can be used to increase the collection efficiency of the conventional air pollution control devices to satisfy the national emission standard.

• 대한환경공학회지
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• 제35권1호
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• pp.17-22
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• 2013

본 연구는 조류 개체 수 증가로 pH가 급격하게 상승한 원수가 정수장으로 유입될 때 pH 조정을 위해 사용하는 이산화탄소($CO_2$) 주입이 응집효율 및 용존 알루미늄 농도변화에 미치는 영향을 고찰하였다. 응집제 1 mg/L에 주입에 따른 pH 감소는 LAS -0.0384, PAC -0.0254, A-PAC -0.0201, PACS2 -0.0135로 나타났다. 용존 알루미늄 농도는 pH 7.44에서 0.02 mg/L, pH 7.96에서 0.07 mg/L, pH 8.16에서 0.12 mg/L, pH 8.38에서 0.39 mg/L로 응집공정의 pH 증가에 따라 용존 알루미늄 농도가 증가하는 것으로 나타났다. 여기서 주목할 점은 급속 교반 후 pH 8.0을 초과할 때부터 용존 알루미늄 농도는 급격하게 증가하는 것이다. 그러므로 높은 pH의 원수가 유입되는 정수장에서 알루미늄 농도가 먹는 물 수질 기준 만족하기 위해서는 응집공정의 pH가 7.8 이하로 유지되도록 공정관리가 필요하며, 원수 pH가 8.0 이상 유입되는 경우 이산화탄소($CO_2$) 주입으로 pH를 7.3 내외로 일정하게 유지할 수 있었다. 또한 이산화탄소($CO_2$) 주입으로 응집공정에서 pH를 조정함으로써 탁도 및 응집제 절감, 용존 알루미늄 농도 감소 효과를 확인할 수 있었다.