• Title/Summary/Keyword: coagulant floc

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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.

Effects of ballasting Agent (Microsand) on Physical Floc Characteristics (세사 투입에 따라 형성된 플럭의 물리적 특성)

  • Ryu, Jae-Na;Lim, Yoon-Dae;Oh, Je-Ill
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.5
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    • pp.485-493
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    • 2010
  • Chemical coagulation destabilizes colloidal particles so that particles grow to larger flocs. Solid particles are then removed by solid-liquid separation after typical precipitation. Rapid precipitation enhances the separation by reducing the precipitation time with larger and denser particles. Conventionally, polyelectolyte compounds (polymers) function as a flocculant aid by introducing a interparticle binding, which increases the particle size and density. And more recent ballasted flocculation adds a ballasting agent (microsand) to form denser particles with its high-density(sp gr=2.65). The current research was to evaluate the manner in which ballasted flocs are formed under different injection timings of microsand and to recognize the effects on floc formation. $FeCl_3$ as a coagulant, anionic polymer for a flocculation aid and microsand were used for the floc formation. Floc size (diameter) was widely ranged with the highest mean value when microsand was injected between $FeCl_3$ and polymer. Mean floc density was larger when the floc formed smaller. Settling velocity increased with larger floc size, whilst not significantly affected by the timing of microsand injection. The additional slow mixing on floc formation increased floc size to some extent.

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.

Determination of Optimum Dosage of Polymer by Zeta potential in the Wastewater Treatment (수처리 시 Zeta전위 측정에 의한 응집제 주입량 결정)

  • Cho, Jun-Hyung;Kang, Mee-Ran
    • Journal of Forest and Environmental Science
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    • v.22 no.1
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    • pp.27-31
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    • 2006
  • Sedimentation characteristics such as SS, COD removal efficiency of wastewater in the toilet paper mill using recycled paper were examined by zeta potential. Optimum dosage of coagulant were determined by turbidity, SS, COD and then equation for treatment efficiency was suggested. Mechanical strength of floc was determined by turbidity.

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Effects of dissolved oxygen and coagulants on algal autoflotation (응집제종류 및 용존산소농도에 따른 조류의 Autoflotation효과)

  • 권오상;박혜경
    • Journal of environmental and Sanitary engineering
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    • v.15 no.1
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    • pp.7-13
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    • 2000
  • To develop the removal technique of algal bloom the efficiencies of algal flocculation/ autoflotation by the kinds of coagulant and oversaturated oxygen concentration were investigated. The summarized results are as follow. 1. In the algae flocculation test with alum[$Al_2(SO_4)_3{\cdot}18H_2O$], optimum pH was 5.5 and, with chitosan optimum pH was 7.0. 2. Chitosan which was natural polymer showed the 5~10 times higher algal biomass flocculation efficiency than alum in the condition of same algal concentration. 3. For the each coagulant, the higher ${\Delta}DO$(oversaturated dissolved oxygen concentration - saturated dissolved oxygen) was, the faster the rising velocity of the algal floc was. 4. In the condition of about 4mg/L ${\Delta}DO$, the rising velocity of chitosan is about 2 times higher than that of alum, and chitosan formed the stronger algal floc.

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Variation of Sedimentation & Dewaterability Characteristics of Sewage Sludge under Various Coagulants (응집제 종류에 따른 하수 슬러지의 침강 및 탈수 특성 변화)

  • Baik, Seon Jai;Jo, Jung Min;Song, Hyun Woo;Han, Ihn Sup
    • Journal of Korean Society on Water Environment
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    • v.30 no.3
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    • pp.311-318
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    • 2014
  • The purpose of this study is to investigate the effect of various types of coagulant on dewaterability and settleability of sewage sludge for the application of dewatering process. Cationic organic coagulants and inorganic coagulants of the aluminium base were used; PAC (Poly Aluminium chloride, $Al_2O_3$ 17%) and C-210P (0.2%). After Jar test, PAC 26 mg/L and 0.2% C-210P 55 mg/L was decided as the optimum concentration of the coagulant according to zeta potential measurement. pH, alkalinity and viscosity were measured in all experiments and the data on sedimentation characteristics is analyzed by SDI, SVI sedimentation rate and solid flux. The SRF(Specific Resistance of Filtration) experiment was conducted with the result of single and dual injection system as the dewaterability experiment. As a result, the organic coagulant making large floc has good characteristics of sedimentation and agglutination. Also, it is observed that the organic coagulants injection has a better dewaterability efficiency of coagulants under the condition of the lowest SRF value, followed by dual and inorganic coagulants injection.

Experimental study on feasibility test for removing particles in air scouring membrane backwash water with metal membrane (금속막을 이용한 저압 막 공기병용 역세척수 처리 타당성 연구)

  • Park, No-Suk;Yoon, Sukmin;Moon, Yong-Taik;Lee, Sun-Ju;Park, Sunghyuk
    • Journal of Korean Society of Water and Wastewater
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    • v.29 no.2
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    • pp.251-259
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    • 2015
  • The main objective of this research is to study feasibility for applying metal membrane to remove particles from air scouring membrane backwash water. Also, the research was conducted to investigate the influence of polyamine coagulation on floc growth in membrane backwash water as pretreatment for removal particles. From the results of experiments for evaluating the influence of polyamine coagulation on floc growth, it was investigated that particles in the rage of $2{\sim}50{\mu}m$ grew up to $30{\sim}5,000{\mu}m$. In addition, all six metal membranes showed lower removal efficiency, which was 0.87~13.89%, in the case of no polyamine coagulant. On the other hand, in the case of injecting polyamine coagulant, those did extremely high efficiency in 56~92%. From the SEM(Scanning Electron Microscope) images of filtered wiremesh and metal foam membrane, sieve effects were predominant for liquid solid separation in wiremesh and adsorption and diffusion capture effects were predominant in metal foam membrane.

Studies on the Determination of Optimal Flocculation Condition in Wastewater of Recycled Paper (재생지 폐수의 최적 응집조건 결정에 관한 연구)

  • 이성호;임택준;조준형
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.33 no.3
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    • pp.44-51
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    • 2001
  • Sedimentation characteristics such as SS, $BOD_5$, COD removal efficiency of waste water in the toilet paper mill using milk carton were examined. Optimum dosage of coagulant, rapid mixing time and slow mixing time were determined by turbidity, SS, COD, $BOD_5$ and then equation for treatment efficiency was suggested. Mechanical strength of floc was determined by turbidity. For the coagulant, polyacrylamide (PAM) is more efficient for removing pollution than the aluminium sulfate. Effective mixing ratios of PAM and aluminum sulfate to remove pollution are 70:30 and 30:70. The lowest turbidity was showed when rapid mixing at 300 rpm after coagulant injection was applied. That which indicates the highest point of flocs mechanical strength.

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Evaluation of Floc Formation Conditions for Increasing Flotation Velocity in DAF Process (DAF 공정에서 부상속도 향상을 위한 플럭형성 조건 평가)

  • Kwon, Soon-Buhm;Min, Jin-Hee;Park, No-Suk;Ahn, Hyo-Won
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.2
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    • pp.245-255
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    • 2006
  • Dissolved air flotation is a solid-liquid separation system that uses fine bubbles rising from bottom to remove particles in water. In order to enhance the flotation velocity and removal efficiency of flocs in the flotation process, we tried to obtain pretreatment conditions for the optimum DAF process operation by comparing and evaluating features of actual floc formation and flotation velocity etc, according to coagulant types and conditions for flocculation mixing intensity by using PIA, PDA, and FSA. Accordingly, generating big flocs that have low density at low flocculation mixing intensity may reduce treatment efficiency. In addition, generating small flocs at high flocculation mixing intensity makes floc-bubbles smaller, which reduces flotation velocity, In this study, it was found that high flocculation mixing intensity could not remove the remaining micro-particles after flocculation, which had negative effects on treated water quality, Therefore, in order to enhance treatment efficiency in a flotation process, flocculation mixing intensity around $50sec^{-1}$ is effective.