• Title/Summary/Keyword: Coagulant Dispersion

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Characteristics of coagulants dispersion within In-Line Orifice Mixer (In Line Orifice Mixer에서의 응집제 확산분포 특성)

  • Lim, Kyeong-Ho;Park, Young-Oh;Park, Dae-Jin;Park, No-Suk;Ko, Tae-Kon
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.6
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    • pp.689-696
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    • 2008
  • In a water treatment process a complete and homogeneous dispersion of the coagulants in the raw water could be most important factor. This research was performed to evaluate coagulation performance of the in-line-orifice mixer which was recently introduced as a rapid mixing device. The test was to determine the actual coagulant dispersion distribution on the overall cross-section at a distance of 1.6~3D from the chemical injection point by measuring zeta potential. From the results of zeta potential test, it was shown that the coagulant dispersion within the in-line orifice mixer was occurred very unevenly. The results have confirmed that it is necessary to increase the velocity of coagulants injection or pressurized water rates, in order to reduce nonuniform distribution of chemicals.

Effects of Dual-Coagulant Performance (이중응집이 응집공정에 미치는 영향)

  • Kim, Hee-Geun;Moon, Byung-Hyun;Kim, Seung-Hyun
    • Journal of Korean Society of Water and Wastewater
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    • v.19 no.1
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    • pp.92-97
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    • 2005
  • This research is to investigate the effect of the dual coagulant using inorganic coagulants($AICl3{\cdot}6H2O$) and polymer on the coagulant process. Jar-test was conducted by using Kaolin injected raw water. PDA(Photometric Dispersion Analyzer) equipment in order to analyze the size of the particles and the characteristics of the shapes. The change in the rate of sample ores' residual deposited after coagulants were also compared. According to the result derived from this experiment, the concentration of inorganic coagulant reduced 50% and the residual was lower by using dual coagulants compared to using single coagulant. However the dual coagulant required sufficient mixing time, and affected particle characteristics, with the effect of the injection order of coagulants, the simultaneous injection of inorganic coagulant and polymer showed the most effective in the particle removal.

Optimum Coagulation of Water Treatment Plant using On-line Floc Monitoring System (정수장 응집제주입 최적화를 위한 플럭 모니터링)

  • Hwang, Hwando;Lim, Sangho;Sung, Kyujong;Han, Youngjin;Kim, Youngbeom;Kwak, Jongwoon
    • Journal of Korean Society of Water and Wastewater
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    • v.23 no.4
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    • pp.397-406
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    • 2009
  • This study was conducted to monitor the floc sizes forming in the mixing zone in the water treatment plant. The dosing amount of poly aluminium chloride(PAC) was determined by particle dispersion analyzer(iPDA) in the lab and field scale test. During a field test period, PAC coagulant was used and the raw water was taken from Nakdong river. PAC wad diluted to activate the coagulant, leading to bring the more homogeneous dispersion in the shorter time. To monitor the floc sizes, the unit of floc size index(FSI) was used. With increasing of raw water turbidity, FSI value was increased. Also, the increased dosing amount of PAC brought the increased FSI and with overdosing of coagulant was in turn decreased. When the PAC was fed into the raw water after dilution in a field scale test, the width of FSI was narrower compared with the feeding of the mother liquor of PAC, implying that the formed flocs are denser and more uniform sizes. The width of FSI in average was varied on depending on the basicity of coagulant. Also, dF value, fractal dimension was evalued with the different coagulants, showing from 2.01 to 2.03. On-line floc monitor was effective for the optimal dosing in the drinking water plant.

Evaluation of Coagulation Characteristics of Fe(III) and Al(III) Coagulant using On-line Monitoring Technique (On-line 모니터링 기법을 이용한 Al염계와 Fe염계 응집제의 응집특성 평가)

  • Son, Hee-Jong;Yoom, Hoon-Sik;Kim, Sang-Goo;Seo, Chang-Dong;Hwang, Young-Do
    • Journal of Environmental Science International
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    • v.23 no.4
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    • pp.715-722
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    • 2014
  • Effects of coagulation types on flocculation were investigated by using a photometric dispersion analyzer (PDA) as an on-line monitoring technique in this study. Nakdong River water were used and alum and ferric chloride were used as coagulants. The aim of this study is to compare the coagulation characteristics of alum and ferric chloride by a photometric dispersion analyzer (PDA). Floc growing rates ($R_v$) in three different water temperatures ($4^{\circ}C$, $16^{\circ}C$ and $30^{\circ}C$) and coagulants doses (0.15 mM, 0.20 mM and 0.25 mM as Al, Fe) were measured. The floc growing rate ($R_v$) by alum was 1.8~2.8 times higher than that of ferric chloride during rapid mixing period, however, for 0.15 mM~0.25 mM coagulant doses the floc growing rate ($R_v$) by ferric chloride was 1.1~2.3 times higher than that of alum in the slow mixing period at $16^{\circ}C$ water temperature. Reasonable coagulant doses of alum and ferric chloride for turbidity removal were 0.1 mM (as Al) and 0.2 mM (as Fe), respectively, and the removal efficiency of those coagulant doses showed 94% for alum and 97% for ferric chloride. The appropriate coagulant dose of alum and ferric chloride for removing dissolved organic carbon (DOC) showed about 0.3 mM (as Al, Fe) and at this dosage, DOC removal efficiencies were 36% and 44%, and ferric chloride was superior to the alum for removal of the DOC in water.

Effect of Coagulant Type on the Silica Dispersion and Properties of Functionalized RAFT ESBR Silica Wet Masterbatch

  • Kim, Woong;Ryu, Gyeongchan;Hwang, Kiwon;Song, Sanghoon;Kim, Wonho
    • Elastomers and Composites
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    • v.55 no.3
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    • pp.167-175
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    • 2020
  • Various studies have been conducted to improve silica dispersion of silica filled tire tread compounds; among them, silica wet masterbatch (WMB) technology is known to be suitable for manufacturing silica filled compounds that have high silica content and high dispersibility. Till now, the WMB study is focused on the natural rubber (NR) or emulsion styrene-butadiene rubber (ESBR) that does not have a silica-affinity functional group, and a study of NR or ESBR having a silica-affinity functional group is still not well known. Unlike the dry masterbatch technology, the WMB technology can solve the problems associated with the high Mooney viscosity when applied to silica-friendly rubber. However, a coagulant suitable for each functional group has not yet been determined. Therefore, in this study, different coagulant applied silica WMB was prepared by applying calcium chloride, sulfuric acid, acetic acid, and propionic acid by using a carboxyl group functionalized reversible addition fragmentation chain transfer ESBR. The evaluation of the WMB compounds revealed that the calcium chloride added WMB compound showed excellent silica dispersion, abrasion resistance, and rolling resistance.

Evaluation of Flow Characteristics within In-Line Mixer for Water Treatment using CFD Technique (CFD모사 기법을 이용한 관내 혼화장치내 흐름 특성 평가)

  • Park, Dae-Jin;Park, Young-Oh;Park, No-Suk;Kim, Seong-Su;Wang, Chang-Kuen
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.3
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    • pp.351-358
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    • 2008
  • The modified in-line mixer which was suggested in this study for small water treatment facilities was evaluated on the performance of coagulation. For the objectives of this research, computational fluid dynamics(CFD) simulation was applied for analysis of flow characteristics within the modified in-line mixer. For verifying the results of CFD simulation, wet tests for the pilot plant were conducted. The wet test was to measure the actual coagulant dispersion distribution on the overall cross-section at a distance of 5.5D from the chemical injection point. From the results of CFD simulation and wet test, it was shown that the coagulant dispersion within the modified in-line mixer was occurred more uniformly than within the existing PDM(Pump diffusion Mixer). The results have confirmed the modified in-line mixer had several advantages compared with the existing PDM in terms of dispersion efficiency.

Evaluation of Coagulants Dispersion in Pump Diffusion Mixer for Water Treatment (CFD모사 기법을 이용한 Pump Diffusion Mixer내의 응집체 확산분포에 대한 평가)

  • Park, Young-Oh;Park, No-Suk;Kim, Seong-Su;Kim, Ki-Don;Lim, Kyung-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.1
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    • pp.49-63
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    • 2008
  • The objectives of this research were to evaluate the pressurized/the main inlet water flowrate ratio which have been used as the most important parameter for operating the pump diffusion mixer until now, to suggest the alternative operating parameter and the relating criteria if the flowrate ratio was not inadequate. For the objectives of this research, computational fluid dynamics (CFD) simulation was conducted for 21 cases of flowrate ratio in full-scaled pump diffusion mixer. From the results of CFD simulation, the local velocity gradient values were calculated in each case in order to analyze the simulation results in more detail. For verifying CFD simulation, wet test was conducted. The wet test was to measure the factual coagulant dispersion distribution at a distance of 5.4m from deflector. From both results of CFD simulation and wet test, flowrate ratio was inadequate as operating parameter or criteria, on the other hand the pressurized/the main inlet velocity ratio(dimensionless) was useful in predicting the performance of pump diffusion mixer. Also, the injected coagulant could be dispersed evenly in overall cross section on the condition that pressurized/the main inlet velocity ratio(dimensionless) is over at least 20.

Influence of Different Mixing Types on the Removal of Natural Organic Matter in Water Treatment (정수처리시 천연유기물질의 제거에 대한 급속혼화유형의 영향)

  • Kim, Hyun-Chul;Yu, Myong-Jin;Lee, Seock-Heon
    • Journal of Korean Society of Water and Wastewater
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    • v.19 no.3
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    • pp.370-377
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    • 2005
  • Dispersion of coagulant should be completed in a fraction of a second before the metal hydroxide precipitate has form. For the reason so-called pump diffusion flash mixing (PDFM) have been proposed, and PDFM is one of reasonable methods to quickly disperse the hydrolyzing metal salts. In this study, therefore, we attempt to understand the difference of removal characteristics of natural organic matter (NOM) between pump diffusion flash mixing (PDFM) and conventional rapid mixing (CRM) for coagulation in a water treatment system, and to enhance the removal of NOM through the improved mixing process. DOC and turbidity removal by PDFM higher than those by CRM, while SUVA value of water treated by PDFM was high as compared with that by CRM. Hydrophilic NOM was more effectively removed by PDFM than CRM, since charge neutralization effect increased by quick dispersion of coagulant. The DBP formation potentials due to NOM was effectively reduced by the improved mixing (i.e., PDFM) for coagulation and could be controlled through decrease in concentration of precursor rather than reduction of activity with disinfectant.

Effects of Temperature on Flocculation Kinetics Using Fe(III) Coagulant in Water Treatment (정수처리시 Fe(III) 응집제를 사용한 응집동력학에 대한 온도의 영향)

  • 강임석
    • Journal of Environmental Science International
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    • v.4 no.2
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    • pp.181-194
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    • 1995
  • Flocculation kinetics using ferric nitrate as a coagulant to coagulate kaolin clay in water was examined as a tool to investigate the effect of low temperature under tightly controlled treatment conditions. Both the particle size distribution data obtained from Automatic Image Analysis (AIA) system and the on-line measurement of the degree of turbidity fluctuation in a flowing suspension by Photometric Dispersion Analyzer (PDA) were used to measure flocculation kinetics. Results show that cold water temperature had a pronounced detrimental effect on flocculation kinetics. For improving flocculation kinetics at low water temperature, maintaining constant pOH to adjust water chemistry for temperature changes was found to be partially effective only in the more acidic pH range studied.

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The Effects of Mixer Geometry on Hydraulic Turbulence : Computational Modeling (3-D 전산유체를 이용한 급속혼화조 형상에 따른 난류 유동장 연구)

  • Park, No-Suk;Kim, Sung-Hoon;Park, Heekyung
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.7
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    • pp.1173-1182
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    • 2000
  • The rapid mixing process has been considered as an important step in water treatment. Since the coagulant dispersion into raw water by rapid mixer can influence on the flocculation and filtration efficiency, many researchers have developed various devices and mixing methodologies. Until now, they focused attention on only coagulant dose, pH. rotating velocity and G value but overlooked the real turbulent flow and mixer geometry in rapid mixer. Therefore this paper questions the significance of turbulent flows in rapid mixer and focuses on the analysis of turbulent fluid in various mixer geometry with CFD(Computational Fluid Dynamics). The results of the jar-tests using various geometries indicate that the turbidity removal rate in a circular jar without baffle is higher than that of a circular with baffle. And the turbidity removal rate in Hudson jar is also founded to be higher than in the circular jar with baffle. The CFD simulation of velocity fields in jar demonstrates that the differences of removal rates among the various geometries are largely due to the formation of the different turbulent fluids fields with different geometries.

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