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DOI : 10.17640/KSWST.2018.26.5.143 , Vol.26, No.5, 143 ~ 154, 2018
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| Title |
| Empirical Evaluation of Microbubble Characteristics for Dissolved Air Flotation System |
| 장향연 Hyang-youn Chang , 박나리 Na-ri Park , 장여주 Yeo-ju Jang , 임현만 Hyun-man Lim , 정진홍 Jin-hong Jung , 김원재 Weon-jae Kim |
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| Abstract |
| The treatment efficiency of dissolved air flotation (DAF) process depends greatly on the operating characteristics of the microbubble generating system. In this study, the indices to compare and quantify the microbubble generation characteristics have been reviewed comprehensively such as ① representative size (㎛), ② number density distribution (counts/mL), ③ specific interfacial area (m2/m3), and ④ specific volume (ppm, v/v). A microbubble generating system utilizing saturation tank type, which has been most commonly applied in DAF processes, was fabricated on a pilot scale and the behavior of the above indicators was monitored while varying the conditions of operating pressure and flow rate. As a result, according to the operating pressure, the representative size increased until the operating pressure reached 3.5 kgf/cm2, and then decreased continuously as the preassure increased. Microbubbles in the range of 20 - 50 ㎛ were formed at the maximum with the condition of 3.5 - 4.5 kgf/cm2. The values of specific interfacial area and specific volume also showed the maximum at 3.5 - 4.5 kgf/cm2. For the operating flow rate, the representative size continuously increased with the increase of the flow rate. The specific interfacial area and specific volume reached their maximum values at the condition of 45 - 50 L/min. As a result of examining the indices of microbubble generation characteristics for a pilot scale generating system, it could be concluded that the applicability of the specific interfacial area and specific volume were better than that of the representative size and number density distribution. |
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| Key Words |
| DAF (dissolved air flotation), Microbubble, Microbubble generating system, Number density distribution, Representative size, Specific interfacial area, Specific volume |
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