정수장 플록형성지의 수리학적 특성과 교반강도가 플록형성 효율에 미치는 영향

정용준 ( Yong Jun Jung ),민경석 ( Kyung Sok Min ) 한국물환경학회 2005 한국물환경학회지 Vol.21 No.3

The main purpose of the flocculation process is to make flocs bigger to be removed easily in the following processes. The flow pattern and mixing intensity have a great influence on flocculation. In this study, the flow pattern was examined by a hydraulic tracer-test, where 3 water treatment plants having 800,000 ㎥/d, 44,000 ㎥/d and 40,000 ㎥/d were employed. Also, the settling test was conducted to find out the relationship between the mixing intensity and the settling ability of flocs. The hydraulic tracer-test was conducted for the various flocculation processes that have different structures of flocculation basins. In the result, the retention time distribution (RTD) curves for the flocculation processes were quite different. In case of the inappropriate structure of the flocculation basin, the flow is not even so that the floc does not grow enough. To find out the relationship between mixing intensity and settleability of flocs, G-values were calculated and the settling test was conducted for two flocculation basins which have the same conditions except the G-value. For the flocculation basin with uneven G-value, the floc settleability was revealed poor. On the other hand, the flocculation basin with even G-value, the settleability was better than the previous one. From these experimental results, it is confirmed that the flow pattern is closely related to the structure of the flocculation basin and the settleability is affected by mixing intensity. Therefore the flow pattern and the strength of the mixing intensity should be examined sufficiently to design and operate flocculation basin.

Flocculation of gelatinized starch: Flocculation performance and floc characterization

Xiaojiao An,Yong Kang,Guishui Li 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.7

The removal of single macromolecules impurity is the basis study for the promotion of flocculation technology application in the Chinese herbal medicine solution purification. We applied the flocculation process to remove gelatinized starch in solution. Three types of cationic polyacrylamide (CPAM) with different charge density were used for flocculation of gelatinized starch solution. The flocculation performance was evaluated in terms of the amylose removal ratio (AMRR), the amylopectin removal ratio (APRR), total starch removal ratio (TSRR) and supernatant turbidity (ST). The flocs were characterized by sedimentation performance, Fourier transform infrared (FTIR), scanning electron microscope (SEM) and X-ray photoelectric spectroscopy (XPS) method. The experimental results show that the flocculant CN15 has the best performance for gelatinized starch flocculation among three flocculants. According to the characterization analysis, the flocs exhibited an obvious network structure, and it is concluded that hydrogen bonding between N-H in CPAM and C-O in the starch and bridging flocculation played the essential roles in flocculation of the gelatinized starch.

Evaluation of Flocculation Performance using Floc Characteristics

Kim, Seung-Hyun,Lee, Hyang-Inn,Yoon, Cho-Hee 대한상하수도학회 2003 상하수도학회지 Vol.17 No.1

This study investigated effects of flocculation time, intensity, and coagulant dosage on flocculation performance using bentonite suspension. These effects were evaluated using such floc characteristics as fractal dimension and size. In terms of fractal dimension and size of flocs, flocculation was complete within 10min for alum coagulation. Fractal dimension and floc size increased with increasing flocculation time, but reached a plateau within 10min. The difference after 10min was not statistically verified. Iron coagulation produced more favorable flocculation for sedimentation. A larger and more regular floc formed at iron coagulation. Cycled flocculation, where floc break-up period was added during flocculation, produced more regular shaped and denser, but smaller flocs than normal flocculation.

Investigation of the effect of water chemistry on biologically mediated flocculation in the aquatic environment

Choi, Jeong Woo,Lee, Byung Joon 한국수자원학회 2017 한국수자원학회논문집 Vol.50 No.11

생체고분자물질은 수자원환경에서 점토, 미생물, 바이오매스 등 부유입자들을 응집시키고, 침전, 퇴적시키는 역할을 한다. 본 연구는 다양한 수질화학 조건이 생체고분자물질에 의한 부유입자 응집에 미치는 영향을 파악하고자, 수질화학 조건을 제어하여 응집실험을 수행하였다. 각 응집실험은 이온강도, 2가 양이온 농도, 휴믹물질 분율이 제어된 실험조건에서 Kaolinite 현탄액에 생체고분자물질인 Xanthan Gum을 주입하여 수행하였다. 수체가 가지는 응집능은 응집체 크기 및 잔류 고형물 농도를 측정을 통하여 평가하였다. 본 연구에서, 이온강도 증가는 점토입자 및 생체고분자물질 간 정전기적 반발력을 감소시키고 생체고분자물질이 점토 입자 간 가교를 형성하여 응집을 증대시킨 것으로 파악되었다. 이온강도가 0.001에서 0.1 M NaCl로 증대될 경우, 응집을 증진시켜 응집체 크기는 약 3배 이상 증 대되고 부유고형물농도는 약 2.5배 이상 저감되었다. 또한, 2가 양이온이 수체에 존재하는 경우, 점토입자-생체고분자물질 혹은 생체고분자물질 상호 간 가교를 형성하여, 즉 점토-Ca2+-고분자 또는 고분자-Ca2+-고분자 가교를 형성하여, 생체고분자물질에 의한 부유입자 응집을 증대시켰다. 수체에 Ca2+가 낮은 농도라도 존재 할 경우, 응집을 크게 증진시켜 부유고형물농도가 원주입농도에 비하여 20배 이상 저감되는 것으로 나타났다. 하지만, 휴믹물질이 존재하는 경우, 점토입자 표면에 흡착되어 점토입자의 정전기적 반발력을 증대시켜 생체고분자물질의 흡착을 방해하고 응집을 감소시켰다. 수체에 휴믹물질이 존재할 경우, 응집을 저감시켜 부유고형물농도는 저감되지 않고 원 주입농도와 유사하게 나타났다. 본 연구의 결과는 수자원환경에서 부유입자 및 퇴적물 거동을 이해하고 수질 및 퇴적물에 대한 최적 관리 방안을 도출하기 위한 기초 자료로 활용될 수 있으리라 기대된다. Extracellular Polymeric Substances (EPS) in the water environment assemble fine, colloidal particles, such as clays, microorganisms and biomass, in large flocs, which are eventually subject to sedimentation and deposition and determine water/sediment quality and quantity. This study hence aimed to investigate the way that water and colloidal chemistry affects EPS-mediated flocculation of colloidal particles, using a jar-test experiment. Especially, ionic strength, divalent cation and humic substances concentrations were selected as experimental variables in the jar-test experiments, to elucidate their effects on EPS-mediated flocculation. A higher ionic strength increased flocculation capability, reducing electrostatic repulsion between EPS-attached colloidal particles and enhancing particle aggregation. 0.1 M NaCl ionic strength had higher flocculation capability, with 3 times larger floc size and 2.5 times lower suspended solid concentration, than 0.001 M NaCl. Divalent cations, such as Ca2+, built divalent cationic bridges between colloidal particles and EPS (i.e., colloid-Ca2+-EPS or EPS-Ca2+-EPS) and hence made colloidal particles to build into large, settelable flocs. A small Ca2+ concentration enhanced flocculation capability, reducing suspended solid concentration 20 times lower than the initial dosed concentration. However, humic substances, adsorbed on colloidal particles, reduced flocculation, because they blocked EPS adsorption on colloidal particles and increased negative charges and electrostatic repulsion of colloidal particles. Suspended solid concentration in the tests with humic substances remained as high as the initial dosed concentration, indicating stabilization rather than flocculation. Findings about EPS-mediated flocculation in this research will be used for better understanding the fate and transport of colloidal particles in the water environment and for developing the best management practices for water/sediment quality.

Flocculation and Formation the Action and Effect

Sang-Gil Lee,Hak Lae Lee,Hye Jung Youn,Young-Bin Jeong 한국펄프·종이공학회 2006 한국펄프종이학회 기타 간행물 Vol.- No.-

Formation which is one of the most fundamental characteristic of paper quality is affected by a number of variables. Fiber flocculation in the headbox has been recognized as the most important variable influencing formation. Consistency and crowding number of headbox stock are known to represent the flocculation potential of stocks. The effects of consistency and crowding number on paper formation were studied by measuring the flocculation of fiber suspensions. Increasing consistency increased the degree of fiber flocculation. Especially the consistency of long fiber fraction was the most crucial factor of flocculation. Tensile strength of handsheets was furnish dependent rather than flocculation dependent. Crowding number of a furnish can be used for the characterization of stock flocculation.

탁도 측정을 통한 점착성 유사의 플록형성 분석

김동현(Dong Hyun Kim),유형주(Hyung Ju Yoo),이승오(Seung Oh Lee) 한국연안방재학회 2020 한국연안방재학회지 Vol.7 No.2

In many estuaries and rivers, the contaminants such as heavy metals have became serious threat to ecosystem including human communities since eagerly development of heavy industrialization. It was found that such materials tended to bound with cohesive sediments, and this bond mechanism is affected by hydraulic characteristics, for instance, turbulence intensity. To understand the complex relationship with the sediment-bond mechanism and hydrodynamics, the study for flocculation which includes the bond between sediment particles without heavy metals should be preceded as the first step. In this study, the flocculation of single sediment (Kaolin) was analysed through laboratory experiments in which the rotational jar-flow was generated and 3D numerical simulation which was performed to obtain the detailed flow fields and calculate hydraulic characteristics. First, the PIV experiment was conducted for the verification of 3D numerical model. And the flocculation index (IF) was proposed to consider the relation with the external energy and average turbulence length scale through the regression approach. The results showed that the flocculation was more affected by turbulence length (eddy size) than by turbulence intensity, and there was the significant specific range of turbulence length about formation of flocculation.

Flocculation Effect of Alkaline Electrolyzed Water (AEW) on Harvesting of Marine Microalga Tetraselmis sp.

( Su-jin Lee ),( Woo-seok Choi ),( Gun-hoo Park ),( Tae-ho Kim ),( Chulhong Oh ),( Soo-jin Heo ),( Do-hyung Kang ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.3

Microalgae hold promise as a renewable energy source for the production of biofuel, as they can convert light energy into chemical energy through photosynthesis. However, cost-efficient harvest of microalgae remains a major challenge to commercial-scale algal biofuel production. We first investigated the potential of electrolytic water as a flocculant for harvesting Tetraselmis sp. Alkaline electrolyzed water (AEW) is produced at the cathode through water electrolysis. It contains mineral ions such as Na⁺, K⁺, Ca²⁺, and Mg²⁺ that can act as flocculants. The flocculation activity with AEW was evaluated via culture density, AEW concentration, medium pH, settling time, and ionic strength analyses. The flocculation efficiency was 88.7% at 20% AEW (pH 8, 10 min) with a biomass concentration of 2 g/l. The initial biomass concentration and medium pH had significant influences on the flocculation activity of AEW. A viability test of flocculated microalgal cells was conducted using Evans blue stain, and the cells appeared intact. Furthermore, the growth rate of Tetraselmis sp. in recycled flocculation medium was similar to the growth rate in fresh F/2 medium. Our results suggested that AEW flocculation could be a very useful and affordable methodology for fresh biomass harvesting with environmentally friendly easy operation in part of the algal biofuel production process.

Flocculation optimization of Spirogyra Using Polyaluminium Chloride

강숭빈,최종일 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Flocculation is known to be one of the most effective ways to harvest microalgae. This study aims to reduce the amount of flocculant and optimize Flocculation conditions to maximize the yield of algal biomass. To achieve this goal, the Response Surface Methodology (RSM) was used to optimize the concentration of coagulant concentration, reaction pH and cell density for harvesting. Response Surface Methodology (RSM) was used to optimize concentrations of flocculant, reaction pH and cell density. Microalgae and Spirogyra varians were flocculated using polyaluminium chloride as an inorganic flocculant. According to the RSM results, the optimal flocculation conditions were calculated with an optical cell density of 0.33 at 5 ppm aluminum chloride, pH 7.5 and OD₆₄₀. The obtained recovery yield of S.varians was 97.6% at the optimal condition.

LAMMER Kinase Lkh1 Is an Upstream Regulator of Prk1-Mediated Non-Sexual Flocculation in Fission Yeast

( Yoon-dong Park ),( Soo Jeong Kwon ),( Kyung Sook Bae ),( Hee-moon Park ) 한국균학회 2018 Mycobiology Vol.46 No.3

The cation-dependent galactose-specific flocculation activity of the Schizosaccharomyces pombe null mutant of lkh1þ, the gene encoding LAMMER kinase homolog, has previously been reported by our group. Here, we show that disruption of prk1þ, another flocculation associated regulatory kinase encoding gene, also resulted in cation-dependent galactose-specific flocculation. Deletion of prk1 increased the flocculation phenotype of the lkh1þ null mutant and its overexpression reversed the flocculation of cells caused by lkh1 deletion. Transcript levels of prk1þ were also decreased by lkh1þ deletion. Cumulatively, these results indicate that Lkh1 is one of the negative regulators acting upstream of Prk1, regulating non-sexual flocculation in fission yeast.

전산유체역학을 이용한 응집지 유입 분배수로의 유량 균등배분에 관한 연구

박진영 ( Chinyoung Park ),전용성 ( Yongseong Jeon ),하현섭 ( Hyunsup Ha ),황태문 ( Tae-mun Hwang ),조정훈 ( Jeonghoon Cho ) 한국수처리학회(구 한국수처리기술연구회) 2018 한국수처리학회지 Vol.26 No.5

The water should be evenly distributed to each flocculation/sedimentation basin because it can affect the floc formation and the efficiency of sedimentation. In order to find the optimum operation method for the equal distribution of the flow rate by using the CFD (Water-CFD), the flow analysis was carried out by considering the basic operation condition and improvement plans. From the results of the CFD simulation, the following conclusions were obtained. When 8 all flocculation/sedimentation basins were operated, the influx of the outermost 1st and 8th flocculation/sedimentation basins were the largest but the amount of 4th and 5th flocculation/sedimentation basins which were located at the center of the distribution channel were the least. The operation rate of water purification plant was 40% compared to facility capacity, therefore it was considered to stop the flocculation/sedimentation basins. The optimum operation method to minimize the influent flow difference was the stopping the 4th and 5th flocculation/sedimentation basins located at the center. The other methods such as the extension of the distribution channel(waterway) and the installation of the disturbance plate near the inlet of flocculation basin need the civil engineering work and the lots of extra costs. However, the effect of the equal distribution is not greater than the change of operation method.