• Title, Summary, Keyword: coagulants

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Characterization of Coagulation on Synthetic Polymerization Al(III) Inorganic Coagulants for Water Treatment (상수처리용 합성 무기고분자 Al(III)계 응집제의 응집특성)

  • Han Seung-Woo;Jung Chul-Woo;Kang Lim-Seok
    • Journal of Environmental Science International
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    • v.8 no.6
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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).

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Nanofiltration of Dyeing Wastewater Using Polyamide Ro-Membranes after the Pretreatment with Chemical Coagulants

  • Hwang Jeong-Eun;Jegal Jonggeon;Mo Joonghwan;Kim Jaephil
    • Korean Membrane Journal
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    • v.7 no.1
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    • pp.58-66
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    • 2005
  • Nanofiltration (NF) of a dyeing wastewater was carried out using polyamide NF-membranes. Before applying the wastewater to the membrane process, it was pretreated with various chemical coagulants such as alum, ferric chloride and HOC-100A. In order to see the effect of the pretreatment of the wastewater using chemical coagulants on the membrane separation process, the optimum conditions for the coagulation and sedimentation process using the chemical coagulants were sought. By the pretreatment, despite the different coagulants used, the chemical oxygen demand (COD) and UV-absorbance of the wastewater were lowered by more than $70\%$. The pretreated wastewater was then applied to the membrane process. The effect of the coagulants used for the pretreatment on the membrane fouling was studied. From this study, it was found that the HOC-100A was the best out of the coagulants used far the removal of the materials that could cause membrane fouling.

The Effects of pH and Dosages According to Qualities of Raw Waters and Basicity of Coagulants (원수 수질특성과 응집제 염기도에 따른 응집 pH 및 주입량의 영향)

  • Park, Noh-Back;Lee, Bum;Tian, Dong-Jie;Lee, Young-Ju;Jun, Hang-Bae
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.5
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    • pp.581-593
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    • 2010
  • The objectives of this study were to investigate the effects of raw water pH and basicity of coagulants on turbidity removal with several raw waters having different level of turbidity, alkalinity and pH. Raw waters were sampled from M, S and B water treatment plants(WTP) located at Miryang, Nakdong, Han river, respectively. Six coagulants which have different levels of basicity and aluminum contents were used for this evaluation. High basicity of the coagulant helped to properly control coagulation processes for treating turbid and low alkali raw water. It was difficult for operators to determine optimum coagulant dose for high basicity coagulants, since residual turbidity tended to decrease continuously as coagulant dose increased. Turbidity removal efficiencies with high basicity coagulants(E and F) were higher than the other coagulants at ambient pH for the M WTP. Turbidity removal efficiencies, however, at adjusted pH 7.0 showed similar among six coagulants. Residual turbidity kept low at excess dosages with high basicity coagulants. Optimum coagulant dosages at adjusted pH 7.0 showed higher than those at ambient pH in M WTP. On the contrary in B WTP, optimum coagulant dosage at ambient pH were higher than that at adjusted pH 7.0.

Enhancement of Dewatering and Settling Characteristics for Swine Wastewater Using Coagulants (응집제를 이용한 양돈폐수의 침감성 및 슬러지의 탈수성 증대)

  • Kang, Seon-Hong;Min, Koung-Suk
    • Journal of Korean Society on Water Environment
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    • v.18 no.3
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    • pp.313-319
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    • 2002
  • Laboratory experiments using metal coagulants[alum, PAC(Poly Aluminum Chloride)] and polymer were conducted in this study to enhance dewatering and settling characteristics for swine wastewater. In this study, application of mixture of metal coagulants and polymer improved settling and dewatering characteristics for swine wastewater compared to using only metal coagulants. Also sludge volume was decreased when the mixture was applied. About 80-90% of settling velocity was increased and thickening ratio was increased as much as two times when adding 100mg/L of cationic polymers. Polymer was excellent for enhancing dewatering property among coagulants.

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.

Combined Effects of Metal Coagulants and Monochloramine on Polyamide RO Membrane Performance (금속성 응집제와 모노클로라민의 상호작용이 Polyamide계 RO막 성능에 미치는 영향)

  • Kim, Kyunghwa;Hong, Seungkwan;Park, Chanhyuk;Yoon, Seongro;Hong, Seongpyuo;Lee, Jonghwa
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.4
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    • pp.637-643
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    • 2006
  • The bench-scale chlorine exposure study was performed to investigate the effect of pretreatment by free chlorine and monochloramine ($NH_2Cl$) on the performance of RO membranes made of polyamide (PA). Feed monochloramination at 2mg/L did not cause significant productivity loss compared to free chlorine. However, metal coagulants reacted with monochloramine, the PA membrane suffered from a gradual loss of membrane integrity by chlorine oxidation, which was characterized as a decrease in salt rejection. Especially, RO membranes exposed to alum coagulants with monochloramine revealed the salt rejection lower than those exposed to iron coagulants. XPS membrane surface analysis demonstrated that the chlorine uptake on the membrane surface increased and carbon peaks were shifted significantly when exposed to alum coagulants with monochloramine.

Formation, Breakage and Reformation of Humic Flocs by Inorganic and Organic Coagulants

  • Kam, Sang-Kyu;Lee, Min-Gyu;Kang, Kyung-Ho;Xu, Mei-Lan
    • Journal of Environmental Science International
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    • v.17 no.3
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    • pp.275-285
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    • 2008
  • The floc formation, breakage and reformation of humic acid by inorganic (alum and PAC) and organic coagulants (cationic polyelectrolytes) at several conditions (pH, ionic strength and floc breakage time) were examined and compared among the coagulants at different conditions using a continuous optical monitoring method, with controlled mixing and stirring conditions. For alum, the shapes of formation, breakage and reformation curves at different pH (5 and 7) were different, but the shapes and the sizes of initial floc and reformed floc were nearly the same in the absence and presence of electrolytes at pH 7. For PAC, similar shapes of the curves were obtained at different pH and ionic strength, but the sizes were different, except for those of reformed flocs at different pH. However, for these coagulants, reformed flocs after floc breakage, occurred irreversibly for all the conditions used in this study. For organic coagulants, the time to attain the initial plateau floc size, the extent of floc strength at high shear rate and reversibility of reformed floes were different, depending floc formation mechanism. Especially, for the cationic polyelectrolyte forming humic flocs by charge neutralization or electrostatic patch effect mechanism, reformed flocs occurred reversibly, regardless of pH and floc breakage time, but occurred irreversibly in the presence of electrolytes.

Characteristics of Adsorption on the RO Membrane Surface by Coagulants Types (응집제 종류에 따른 RO막 표면 흡착 특성)

  • Jeong, Youngmi;Park, Chanhyuk;Lee, Sanghyup;Kweon, Jihyang
    • Journal of Korean Society of Water and Wastewater
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    • v.21 no.4
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    • pp.477-483
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    • 2007
  • A coagulation process for RO (reverse osmosis) membrane pretreatment system was an effective technology to remove colloidal and particulate matters. However, coagulant residuals from the pretreatment process may negatively affect RO membrane performance. The bench-scale coagulant exposure study was performed to investigate the effect of their residual on adsorbed mass which related to the membrane performance. Coagulant addition in this study ranged from 0 to 5mg/L ferric chloride, alum, and 2mg/L cationic polymer(poly-di-methyldiallyl ammonium chloride) as coagulant aids. This results showed that adsorbed mass is not significantly increased during short-time period, however, accumulated mass of coagulants on the membrane surface is significantly increased during long-time experimental period. The effect of pH on coagulants adsorption characteristics was significantly differed due to the electrostatic repulsive interactions between soluble coagulants and membrane surface charge. This data suggest that the RO membrane performance of drinking water treatment plant could be decreased by adsorption of residual coagulants when applied for the coagulant pretreatment process.

Addition of Coagulants for Phosphorus Removal from Combined Sewer Overflows (CSOs) (합류식 하수관거 월류수의 인제거를 위한 응집제 투여)

  • Son, Sang-Mi;Jutidamrongphan, Warangkana;Park, Ki-Young
    • Journal of Korean Society of Water and Wastewater
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    • v.26 no.2
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    • pp.295-302
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    • 2012
  • The coagulation of combined sewer overflows ($CSO_{s}$) was investigated by jar-testing with several commercial coagulants. $CSO_{s}$ sample showed different characteristics of coagulation from secondary wastewater with three common coagulants, aluminum sulfate, ferric chloride and polyaluminum chloride (PACl). Jar-tests showed that relatively wide range of optimal SS and T-P removal yielded with alum and ferric chloride compared with cationic polymers, though efficient SS and T-P removal can be achieved with all three coagulants. The decrease of pH was caused by the increase in dosage of aluminum sulfate, ferric chloride and PACl as coagulants. The pH was changed from 7.0 to 4.7 with the dosages of ferric chloride 25 mL/L. Aluminum sulfate revealed pH of 5.0 and PACl was highest pH of 5.4 after dosing of coagulants. The optimal pH to treat $CSO_{s}$ with aluminum sulfate were 6-6.5; with PACl 6-7, and with ferric chloride higher than 7.

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.