• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1189-1193
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• 2007

국내 정수장내 설치되어 있는 혼화기는 대부분 기계식 급속혼화 방식을 채택하여 운영하고 있으며 대부분의 혼화지가 크게 설계되어 설계 변경을 하지 않고서는 혼화 효율을 높이는 한계가 있다. 혼화지내 격벽을 설치하여 혼화 구간을 축소시킴으로써 혼화구간이 큰 구조에 비해 6.27%의 효율이 더 좋은 것으로 나타났으며 격벽이 설치된 혼화구간내에 임펠러는 격벽으로 둘러싸인 유출부쪽(상단부)에서 85.45%로 가장 좋은 효과가 나타났다. 또한 약품위치가 임펠러 하단에 가까우면 혼화효과가 크며 멀 경우에 격벽설치에 따른 혼화효과가 더욱 큰 것으로 나타났다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.842-846
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• 2008

원수의 탁질 중에서 입경이 $10^{-1}$mm이상인 것은 보통침전으로 제거가 가능하지만, 입경이��$10^{-3}mm$이하가 되면 일반적으로 콜로이드입자라고 총칭하며 그대로의 상태로서는 거의 침강되지 않을 뿐만 아니라 급속여과기구에서도 포착되지 않는다. 따라서 급속여과 방식에서는 이와 같은 탁질을 효과적으로 제거하기 위한 전처리로서 응집조작으로 인한 콜로이드상의 탁질을 플록화하여 약품침전이나 급속여과에서 포착되도록 탁질의 성상을 변화시키는 조작이 반드시 필요하다. 또한 양호한 플록을 효과적으로 형성시키는 약품혼화와 플록형성 등을 강구해야 한다. 이에 본 연구에서는 현재 국내에서 운영하고 있는 정수처리시스템의 일부인 혼화지내에 혼화지점의 단면적을 축소시켜 약품혼화효과를 극대화하고 혼화기의 소요동력을 감소시켜 혼화효과를 개선하며 혼화지내 혼화기 운용의 비용 절감 효과를 증가시키기 위한 저에너지형 CF혼화장치를 개발하는데 연구 목적이 있다. 연구결과 CF혼화장치의 설치시 약품 투입 위치에 따라 $2{\sim}6%$정도의 탁도제거율의 상승과 슬러지 높이의 차이를 보이는 것으로 나타났으며 이 실험 결과 약품투입장소에서 혼화지의 Compact화로 인해 급속 혼화를 이룰 경우 더 많은 플록화로 인해 탁도 제거율이 높아지는 것을 알 수 있다.

• Journal of computational fluids engineering
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• v.22 no.1
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• pp.1-7
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• 2017

The mixing of water and chemicals is an important process in the water purification plant. In this paper, we compare PDM(pump diffusion mixer) and hydraulic mixer at the basin in the mixing process. The proper flow rates are predicted and compared in both mixers using CFD technique. As a result, the flow rate of purifier chemical liquid should be 5% of that of water for the optimal performance of mixing process. The characteristics of the two mixing methods are compared with each other for strong and weak points on the operation of the purification system, discussed in the view point of CFD simulations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.6-13
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• 2017

This study examines the effect of the type and number of orifices in an in-line mixer to improve the mixing performance and pressure loss. Recently, in-line non-power-consuming mixers have been increasingly used to complement mechanical mixers, which have a long dwell time, noise, excessive energy consumption, and high maintenance costs. An in-line mixer with an orifice for efficient mixing in water treatment was examined by numerical analysis using the commercial code FLUENT. The flow characteristics of pressure loss and velocity distribution within the mixer and the mixing efficiency were compared with and without the orifices. The CFD results show that the mixing efficiency was improved, but the pressure loss was increased by the in-line mixer with an orifice. A sensitivity study was also done on the principal parameters.

• Journal of Korea Water Resources Association
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• v.30 no.6
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• pp.731-741
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• 1997

Optimum design conditions of rapid mixing impellers for an effective Water Treatment Plant operation were experimentally studied by thorough examination of parameters, such as impeller type and detention time. which govern the removal efficiency of turbidity. It was found that the impeller type is one of the major parameters governing the economic power consumption and the efficiency of turbidity removal. The experimental results showed that not only the velocity gradient G but also a new design guide. so called mixing energy per unit volume of raw water, could be used as a design and operation guides for rapid mixing in W.T.P.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.52-58
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• 2005

To establish low-cost and high efficiency water treatment process, feasibility of applying ultrasonic spray nozzle for chemical injection was evaluated. Ultrasonic spray nozzle was manufactured using piezoelectric ceramics. Treatment efficiencies of contaminants by ultrasonic spray nozzle were compared with conventional chemical mixing such as back-mixing. It was found out that the rate of chemical diffusion rate by ultrasonic spray nozzle was faster than by back-mixing method. Removal efficiencies of various contaminants, such as turbidity, organics and microorganism by ultrasonic spray nozzle were also higher than by back-mixing method. By adapting ultrasonic spray nozzle in coagulant injection process, it can be prevented that the decline of treatment efficiency by coagulant overdose. The amount of coagulant can be reduced by applying ultrasonic spray nozzle in water treatment. Along with these advantages chemical mixing chamber is not required if ultrasonic spray nozzle is adapted. From these results, it can be concluded that chemical injection by ultrasonic spray nozzle is an economical and highly efficient device for coagulant mixing.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.706-713
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• 2017

This study compared and analyzed the water treatment efficiency and the applicability of water treatment plant using the existing Mechanical Rapid-Mixer by introducing the Non-powered Vortex Mixer to the domestic water treatment plant. For this study, fluid flow characteristics and head loss of a Non-powered Vortex Mixer are calculated by Computational Fluid Dynamics (CFD)respectively. The head loss rate inside the mixer was 11.30% when the inflow velocity was 0.5 m/sec, 16.27% at 0.6 m/sec and 21.44% at 0.7 m/sec, the head loss rapidly increased at the optimal velocity of 0.5 m/sec. For the inflow velocity of 0.5 m/sec, the turbulent intensity at the inlet was 2.37% and at the outlet was 7.83%, so there was sufficient mixing strength for the particulate matter and the coagulant. The result of the water quality of the treatment plants with the inflow velocity of 0.38 m/sec that was operated in three years after replacing all 12 units of the existing Rapid-Mixer with the Non-powered Mixer met the standards. Hence, it is possible to reduce the energy consumption of 64,143 ~ 65,306 kWh/year since the Rapid-Mixer is replaced by the Non-powered Vortex Mixer.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.4
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• pp.65-71
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• 2003

A new type of ultrasonic spray nozzle was fabricated employing a piezoelectric device. The spray nozzle was designed to disperse chemicals in a water treatment mixing tank. The piezoelectric properties in ultrasonic spray nozzles were optimized to improve the dispersion of chemicals. The piezoelectrics were packaged in an aluminum case with silicone resin for the aqueous solution proof packaging. Chemicals were dispersed with high efficiency and the chemicals consumption was reduced by the ultrasonic fine particle spraying. The concentration of Escherichia coli in mixing tank was decreased remarkably using ultrasonic spray nozzle dispersion compared to the conventional methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1452-1457
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• 2011

Strength properties of cement mortar was carried out silica fume(SF) and Titanium Dioxide($TIO_2$) by nano admixture of dry process and wet process. Experimental parameters were Nano admixture as the dry process and wet process 5, 10, 15 or 20%. As a result, strength properties of cement mortar by silica fume(SF) and Titanium Dioxide($TIO_2$) were similar and in a comparative experiment of the dry process and wet process Nano admixture using wet process Nano admixture showed a greater strength properties.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.437-443
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• 2018

This study investigates the effect of the mixing elements on the pressure loss and mixing performance in line mixer. The high density ozone water devices mixed with gas and liquid are used in various fields such as sterilizing of group feeding facilities and water quality management at a fish farm. Due to the decrease in rainfall due to climate change, pasteurization of drinking water from ground water and surface water is extremely important. Therefore, it is intended to develop a line-mixed gas liquid mixer with a small amount of space. In this study, the effects of the number of static mixers and the types and the number of the orifice used in line mixer on the volume fraction and the pressure loss were studied by CFD simulation. The pressure drops of line mixer with orifice which curved vanes were attached to were down to more than 50 percent of that of line mixer with static mixer whereas the mixing performance of the former was similar to that of the latter.