• 한국대기환경학회지
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• 제16권1호
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• pp.1-10
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• 2000

The behavior of aerosos due to gravitational coagulation was studied experimentally and numerically. In experimental study, the geometric mean particel size increased as time elapsed in a vertical tube column, while the size decreased when the tube was set horizontally. The particle size distribution was observed to maintain the lognormal form during the coagulation process. Separately, numerical calculations were performed for studying the aerosol behavior under gravitational and Brownian coagulation using the moment method. By comparing the expeimented results with the numerical predictions, the governing mechanism of the aerosol behavior proved to be gravitational coagulation.

• 상하수도학회지
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• 제20권2호
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• pp.235-244
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• 2006

A PCF(Pore Controllable Fiber Filter) process was applied as a pretreatment of water treatment for reduction of turbidity. The experimental results obtained from the PCF showed that the removal efficiency of turbidity without coagulation was around over 70 percent. However, the removal efficiency of turbidity by the coagulation-PCF process was high as much as over 95%. Thus, the coagulation pretreatment was required for the better operation of the PCF. The SEM (Scanning Electron Microscope) images of fiber before and after filtration showed that the filtration mechanism of PCF filter is both controlling attachment mechanism and Sieving mechanism through fiber pore. For the coagulation-PCF process, optimum dosage of coagulant was needed for the economical operation, and for this, determining the optimum dosage by using a filter column test. Also only 16mg/L of alum was used to obtain high algae removal efficiency over 90%. Therefore, it can be concluded that coagulation-PCF process is very effective pretreatment process for algae removal.

• 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.

• 한국광학회지
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• 제24권6호
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• pp.338-341
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• 2013

본 논문에서는 혈액의 응고 시간을 나타내는 잣대로 활용되는 PT (prothrombin time)를 반사광을 이용하여 측정하는 방법에 대한 광학적 분석이 기술된다. 혈액에 일정량의 thromboplastin을 정량 추가하면 혈액의 응고 과정이 진행된다. 응고 시간을 측정하기 위하여 혈액에 자성 철 가루를 혼입하고 자석을 회전시키면서 혈액 표면을 레이저로 조사하여 그 반사광의 변화를 측정하였다. 이 신호를 분석하면 표준 값에 대응하는 PT 값을 환산할 수 있었다. 측정된 반사광 신호를 전산 모델링으로 나타내어 측정 원리를 분석한 결과도 같이 제시한다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 가을 학술발표회 발표논문집
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• pp.319-321
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• 2003

This research was carried out to evaluate the removal efficiencies of CODcr and colour for the dyeing wastewater by ferrous solution in Fenton process. The results showed that COD was mainly removed by Fenton coagulation, where the ferric ions are formed in the initial step of Fenton reaction. On the other hand colour was removed by Fenton oxidation rather than Fenton coagulation. The removal mechanism of CODcr and colour was mainly coagulation by ferrous ion, ferric ion and Fenton oxidation. The removal efficiencies were dependent on the ferric ion amount at the beginning of the reaction. However the final removal efficiency of COD and colour was in the order of Fenton oxidation, ferric ion coagulation and ferrous ion coagulation. The reason of the highest removal efficiency by Fenton oxidation can be explained by the chain reactions with ferrous solution, ferric ion and hydrogen peroxide.

• 상하수도학회지
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• 제17권4호
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• pp.519-527
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• 2003

Cake layer in crossflow microfiltration(CFMF) can be reduced by coagulation, enhancing membrane flux. This is because enlarging particle size by coagulation increases shear-induced diffusivity and the back-transport of rejected particles. However it is known that the enlarged particles are disaggregated by the shear force of the pump while passing through it. This study is to look at the disaggregation in relation with cake layer reducation. Kaolin and polysulfon hollow fiber microfilter are used for experiment. The reduction of cake resistance by coagulation is observed in a range of 17% to 53% at the various coagulation conditions. The particle size analysis results of the experiments show that aggregated particles in feed are completely disaggregated by pump but re-aggregation of particles occurs in membrane. This suggestes that the re-aggregation of particles is critical to cake reduction and flux enhancement, since the aggregated particles are completely broken. The mechanisms for re-aggregation in membrane are the same with those for coagulation in feed tank. Charge neutralization is better for CCFMF than sweep flocculation although it has two drawbacks in operation.

• 한국환경과학회지
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• 제8권6호
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• pp.717-724
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• 1999

This experiment was performed on three parts with prepared coagulants. (1) The characterization of coagulation for PACI coagulants. (2) Comparison of the characterization of coagulation with PAS and PACI coagulants. And (3) Comparison of the characterization of coagulation for the addition of calcium with PACI. Coagulation experiments were conducted with several dosages and pH for each coagulants. For the characterization of coagulation with PACI coagulants, coagulation of Nakdong river waters with three PACls (r=2.0, 2.2, 2.35) showed that the effectiveness of the three coagulants can be considered as r=2.2 > 2.0 > 2.35 which are also the order of higher polymeric aluminum contents. For the comparison of the characterization of coagulation for PAS and PACI coagulants, PAS (r=0.75) coagulants was more effective than other coagulant for the removal of organic matters by sweep floc mechanism with $A;(OH)_{3(S)}$. For comparison of the characterization of coagulation for the addition of calcium with PACI, the presence of divalent cation like $Ca^{2+}$ was supposed to influence the complex formation of organic anions. From the result of test on coagulation at various pH ranges, the PACI was least affected by the coagulation pH, and the addition of calcium to PACI was very effective for the removal of turbidity and organic materials over broader pH range (pH 4-9).

• 한국환경과학회지
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• 제13권11호
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• pp.987-991
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• 2004

The purpose of this research is to evaluate the removal efficiencies of COD$\_$Cr/ and color for the dyeing wastewater by the different dosages of ferrous solution and H$_2$O$_2$ in Fenton process. In the case of H$_2$O$_2$ divided dosage for the Fenton's reagent 7:3 of H$_2$O$_2$ was more effective than 3:7 to remove COD$\_$Cr/ and color. The results showed that COD$\_$Cr/ was mainly removed by Fenton coagulation, where the ferric ions are formed in the initial step of Fenton reaction. On the other hand color was removed by Fenton oxidation rather than Fenton coagulation. The removal mechanism of COD$\_$Cr/ and color was mainly coagulation by ferrous ion, ferric ion and Fenton oxidation. The removal efficiencies were dependent on the ferric ion amount at the beginning of the reaction. However, the final removal efficiency of COD$\_$Cr/ and color was in the order of Fenton oxidation, ferric ion coagulation and ferrous ion coagulation. The reason of the highest removal efficiency by Fenton oxidation can be explained by the chain reactions with ferrous solution, ferric ion and hydrogen peroxide.

• 한국식품과학회지
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• 제29권4호
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• pp.817-822
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• 1997

구름버섯 자실체에서 분리된 항응고성 다당류의 혈액응고 저해기작을 검토하였다. 항응고성 다당(CV-40-Va-1)은 vWF의 활성을 감소시킴으로써 혈소판응집을 억제시키는 것으로 나타났으며, 혈액응고인자중 thrombin뿐만이 아니라 내인성경로의 factor VII, IX, XI, XII의 활성 또한 억제 하였다. 그러나 CV-40-Va-1의 항응고 활성은 thromin에 직접 작용하는 것이 아니라 antithrombin III 의존적 활성을 보였다. Sulfation에 의하여 CV-40-Va-1의 항응고활성의 증가와 다당의 desulfation시 상반된 결과에서 CV-40-Va-1의 황산기가 항응고활성의 중요한 인자임을 알 수 있었다. CV-40-Va-1을 TFA로 부분가수분해하여 얻은 획분들(Fr.I, Fr.II)에서는 항응고 활성이 감소하였으나 분자량 1,000정도로 추정되는 획분(Fr.II)은 오히려 혈소판응집을 강력하게 억제하였다.

• 상하수도학회지
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• 제20권4호
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• pp.559-571
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• 2006

The overall objective of this research was to find out the interrelation of coagulant and organic matter during rapid mixing process and to identify the change of organic matter by mixing condition and to evaluate the effect of coagulation pH. During the coagulation, substantial changes in dissolved organics must be occurred by coagulation due to the simultaneous formation of microflocs and NOM precipitates. Increase in the organic removal efficiency should be mainly caused by the removal of microflocs formed during coagulant injection. That is, during the mixing period, substantial amount of dissolved organics were transformed into microflocs due to the simultaneous formation of microflocs and NOM precipitates. The results also showed that 40 to 80% of dissolved organic matter was converted into particulate material after rapid mixing process of coagulation. During the rapid mixing period, for purewater, formation of dissolved Al(III) (monomer and polymer) constant by rapid mixing condition, but for raw water, the species of Al hydrolysis showed different result. During the rapid mixing period, for high coagulant dose, Al-ferron reaction increases rapidly. At A/D(Adsorption and Destabilization) and sweep condition, both $Al(OH)_3(s)$ and dissolved Al(III) (monomer and polymer) exist, concurrent reactions by both mechanism appear to cause simultaneous precipitation.