• 한국산업융합학회 논문집
• /
• 제11권3호
• /
• pp.107-111
• /
• 2008

Usually, flow mediation earth and settling pond etc. of processing plant to handle water or wastewater. Mediation is the wastewater that flowed past settling pond than material of heavy particles, water weight colloid particles that big solids are removed but are suspensibility material settlement exclusion impossible. So, we need flocculation and coagulation action to remove materials from this colloid state. Flocculation and coagulation by addition of chemical agents forms floc settle size. That is, shorten the sedimentation time and quality of processing water because promoting sedimentation doing to do fines or suspended solids and colloid can materials large size and also, flocculation to annex efficiency of filtration augment. Therefore, I executed this research to prove that COD efficiency for wastewater by using inorganic coagulant.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 B
• /
• pp.952-954
• /
• 2000

In the cleaning-water treatment process, the flocculation machine is operated by the V.S motor when the coagulation-facility of the coagulation-process is operated. But after the flocculation machine is stopped by an instantaneous power failure, the transient takes place when the coagulation facility is re-started. To improve the transient state, we developed the reinforcement-circuit which had the function of soft-start and adapted to the field. As a result of this study, we reduced the damage of facilities and had the safety in maintaining the quality of water and improved the efficiency in the maintenance and the management.

• 한국전산유체공학회지
• /
• 제21권3호
• /
• pp.24-30
• /
• 2016

In the water purification plant, the mixture of water and chemical from the mixing basin enters the flocculation basin. The rotating flocculators are generally used for the efficient flocculation of dregs. In this paper, the performance of flocculators of a vertical paddle type, widely used in the typical flocculation basins, and a hydro-foil type, recently disseminated in the field, are compared with each other by use of the numerical method. Also the characteristics and the efficiency are analyzed with CFD techniques. The strain rate and the eddy viscosity are compared for two types to predict the mixing efficiency, and the maximum speed and its location are pursued from the computed data. The hydrofoil type shows that the eddy viscosity is enhanced 1.66 to 3.03 times larger than that of vertical paddle type, and also produced 1.87 to 1.95 times larger flocs for each stage. However, the rapid rotation of hydrofoil may chop the floc to small size due to the higher turbulence intensity. From the result of computation, the strong and weak points of each type have been analyzed for the decision making.

• KSBB Journal
• /
• 제27권2호
• /
• pp.103-108
• /
• 2012

The harvesting of microalgae is a critical step that precedes biodiesel conversion. The most widely used harvesting technology is flocculation and floatation. In this study, the efficiency of the flocculants aluminum sulfate and poly aluminum chloride were evaluated for harvesting the alga Dunaliella tertiolecta in conjunction with dissolved air floatation. Using the jar test the optimum concentration range for aluminum sulfate was 1.0~1.5 g/L and for poly aluminium chloride, 1.5~2.0 g/L. The degree of coagulation was visualized by microscopy. Further analysis in combination with dissolved air floatation showed that the optimal concentration for aluminum sulfate was 1.1 g/L and for poly aluminum chloride, 1.6 g/L.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
• /
• pp.176-177
• /
• 2005

KOWACO - ChangWon Branch - have conducted the new study which aimed to improve flocculation performance in Mixers. The Purposes in this study were increasing flocculation efficiency by finding significant factor which was affected flow characteristics. In the result of this research we modified the error in equation of G-value and RPM which have been used till quite recently. Also we developed program auto-calculating G-value and RPM and then we had made their statistical list. We had conducted experiment with flocculation Mixer's model sized 1/10 by PIV's method. We analysed characteristic of all flow fields by changing case such as changing direction of flocculator roatation etc.

• 펄프종이기술
• /
• 제32권4호
• /
• pp.18-26
• /
• 2000

In order to investigate the influencing factors in flotation fractionation, flotations were performed at varied conditions. The selectivity of fines fractionation was mainly affected by long fiber flocculation degree and if there were not sufficient flocculation of long fibers, more loss of long fibers could not be avoided. The amount of flotation rejects were totally dependent on the stability of froth floated on the stock surface. Only small size fines could stabilize the froth as they hindered the drainage of liquid lamella in flotation-froth. More flotation reject and better flocculation of long fibers were two important factors for improving flotation. Changing a flotation flux or an air-mixing ratio to increase the flocculation of fibers increased long fiber ratio in the reject. In order to satisfy the both conditions of reducing long fiber loss and of increasing flotation reject, search of fractionation promoter is needed.

• 한국산학기술학회논문지
• /
• 제15권12호
• /
• pp.7438-7442
• /
• 2014

정수처리공정 중 응집공정의 효율을 평가하기 위하여 Floc Size 분포를 분석하여 응집공정의 효율 평가를 수행하였다. 응집 효율은 탁도를 기준으로 평가하는 방법보다 응집 상태를 직접 평가하는 Floc의 크기 및 개수를 분석하여 정량화하는 기법을 제시하였다. 원수의 탁도 분포에 따른 Floc의 성장 상태를 분석하였다. 응집지에서 원수 탁도가 5.0 NTU 내외로 유입되었을 경우 응집지 각 단의 G값이 각각 50 sec-1,, 30 sec-1, 10 sec-1일 때 효율이 가장 높게 나타났으며, 원수 탁도가 263 NTU로 유입되었을 경우 G값을 각각 65 sec-1, 40 sec-1, 10 sec-1으로 운전한 경우 효율이 가장 높게 나타났으며, 이때 $1200{\mu}m$ 이상의 Floc 개수는 약 14개로 분석되었다. G값에 따라 응집효율을 평가할 수 있는 지표인자로 Floc의 크기 및 개수로 공정 진단 수행이 가능할 것으로 판단된다.

• 한국유체기계학회 논문집
• /
• 제8권3호
• /
• pp.33-41
• /
• 2005

The optimum condition is defined as one that best suits the purpose of flocculation; the number of small particles should decrease, while that of large particles should increase. The object of this research was to develop a new impeller and substitute for conventional flocculators. The flow characteristics of turbines and hydrofoil type flocculators in turbulent fluids were observed using a standard $k-{\epsilon}$ Model and a computational fluid dynamics (CFD) simulation program-FLUENT. The experiments were performed to compare PBT(Pitched Blade Turbine) flocculator with twisted hydrofoil type flocculators for velocity distribution, and floe formation at conventional water treatment plants in Korea. As a result of the CED solution, twisted hydrofoil types are similar to hydrofoil flocculators for flow characteristics without regard to the twisted angle, On the other hand, it was established that turbine flocculators are greater than hydrofoil flocculators with flow unevenness and dead zone formation. Twisted hydrofoil type-II (Angle $15{\sim}20^{\circ}$) is the most proper impeller for water flocculation from this point of view with a decreasing the dead zone, maintaining of the equivalent energy distribution and a drawing up of the sedimentation substance from the bottom of the flocculation basin.

• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
• /
• pp.267-274
• /
• 2004

The optimum condition is defined as one that best suits the purpose of flocculation; the number of small particles should decrease, while that of large particles should increase. The object of this research was to develop a new impeller and substitute for conventional flocculators. The flow characteristics of turbines and hydrofoil type flocculators in turbulent fluids were observed using a standard k-$\epsilon$ Model and a computational fluid dynamics (CFD) simulation program- FLUENT The experiments were performed to compare PBT(Pitched Blade Turbine) flocculator with twisted hydrofoil type flocculators for velocity distribution, and floc formation at conventional water treatment plants in Korea. As a result of the CFD solution, twisted hydrofoil types are similar to hydrofoil flocculators for flow characteristics without regard to the twisted angle, On the other hand, it was established that turbine flocculators are greater than hydrofoil flocculators with flow unevenness and dead zone formation. Twisted hydrofoil type- II (Angle $15{\~}20^{\circ}$) is the most proper impeller for water flocculation from this point of view with a decreasing the dead zone, maintaining of the equivalent energy distribution and a drawing up of the sedimentation substance from the bottom of the flocculation basin.

• Journal of Microbiology and Biotechnology
• /
• 제28권3호
• /
• pp.432-438
• /
• 2018

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 $Na^+$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$ 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.