Journal of Korean Society of Environmental Engineers (대한환경공학회지)

Korean Society of Environmental Engineers (대한환경공학회)
권호 표지
DOI QR코드

DOI QR Code

Efficient Micro-Ozone-Bubble Generation by Improving Ozone Dissolution Tank Structure

오존용해탱크 구조 개선을 통한 효율적인 마이크로오존버블 생성

  • Park, Yong-hwa (Graduate School of water Resources, Sungkyunkwan University) ;
  • Lee, Gwang-hi (Research institute at Haesung Engineering Inc) ;
  • Jang, Am (Graduate School of water Resources, Sungkyunkwan University)
  • 박용화 (성균관대학교 수자원전문대학원) ;
  • 이광희 (해성엔지니어링(주) 기술연구소) ;
  • 장암 (성균관대학교 수자원전문대학원)
  • Received : 2017.09.14
  • Accepted : 2017.10.16
  • Published : 2017.10.31
⟨ Previous Next ⟩

Abstract

The purpose of this study is to investigate how ozone-dissolution-tank structure affects micro-ozone-bubble distribution, energy consumption and water treatment efficiency. The partition walls inside the ozone-dissolution-tank generate pressure changes, shear forces, and swirling flows, which change the size of the bubble diameter. The size of the bubble diameter differs by 10.5% depending on the partition walls. Changes in ozone-bubble diameter are related to energy consumption. As the ozone-bubble becomes smaller, the bubble generation energy increases, but the ozone production energy decreases as the dissolution efficiency increases. Therefore, an ozone-dissolution-tank should be determined by means of an optimal condition producing a micro-ozone-bubble with a minimum sum of bubble generation energy and ozone production energy. The energy consumed to inject the same amount of ozone into the effluent differs by 2.5% depending on the partition walls. However, considering the water treatment efficiency, the conditions for selecting the ozone-dissolution-tank are variable. This is because the free radicals that increase as the ozone-bubble gets smaller are very efficient for water treatment. Even at the same ozone injection concentration, the water treatment efficiency differs by 10.4% according to the partition walls. Therefore, we have studied ozone-dissolution-tank structure which produces reasonable ozone-bubble considering water treatment efficiency and energy efficiency.

본 연구는 오존용해탱크 구조에 따라 마이크로오존버블의 분포, 에너지 소비, 수처리 효율이 어떻게 변하는지를 알아보고자 하였다. 오존용해탱크 내부의 격판은 압력의 변화, 전단력, 선회유동을 발생시키고 이는 버블 직경의 크기에 변화를 준다. 버블 직경의 크기는 내부의 격판에 따라 10.5%까지 차이가 났다. 오존 버블 직경의 변화는 에너지 소비와 관련이 깊다. 오존 버블이 작아질수록 버블생성에너지는 높아지지만 용존 효율이 올라가면서 오존생산에너지는 줄어들게 된다. 따라서 버블생성에너지와 오존생산에너지의 합이 최소인 마이크로오존버블을 생성하는 오존용해탱크를 선정하여야 한다. 동일한 양의 오존가스을 방류수에 주입하기 위해 소비된 에너지는 내부의 격판에 따라 2.5%까지 차이가 났다. 하지만 수처리 효율까지 고려한다면 오존용해탱크 선정 조건이 달라진다. 오존 버블이 작아질수록 증가하는 자유라디칼이 수처리에 매우 효율적이기 때문이다. 동일한 오존주입농도에서도 내부의 격판에 따라 수처리 효율이 10.4%까지 차이가 났다. 따라서 수처리 효율과 에너지 효율을 고려하여 합리적인 마이크로오존버블을 생성하는 오존용해탱크 구조에 대하여 연구하였다.

Keywords

Acknowledgement

Supported by : 환경부

References

  1. Khuntia, S., Majumder, S. K. and Ghosh, P., "Microbubble-aided water and wastewater purification: a review," Rev. Chem. Eng., 28(4-6), 191-221(2012).
  2. Takahashi, M., Chiba, K. and Li, P., "Free-radical generation from collapsing microbubbles in the absence of a dynamic stimulus," J. Phys. Chem. B., 111(6), 1343-1347(2007). https://doi.org/10.1021/jp0669254
  3. Carey, V. P., "Liquid-vapor Phase Change Phenomena,"(1992).
  4. Takahashi, M., "${\zeta}$ potential of microbubbles in aqueous solutions: electrical properties of the gas-water interface," J. Phys. Chem. B., 109(46), 21858-21864(2005). https://doi.org/10.1021/jp0445270
  5. Terasaka, K., Hirabayashi, A., Nishino, T., Fujioka, S. and Kobayashi, D., "Development of microbubble aerator for waste water treatment using aerobic activated sludge," Chem. Eng. Sci., 66(14), 3172-3179(2011). https://doi.org/10.1016/j.ces.2011.02.043
  6. Somiya, I., "Ozone handbook,"(2004).
  7. Lee, S. H., Jung, K. J., Kwon, J. H. and Lee, S, H., "A study on the solubilisation of excess sludge using microbubble ozone," Korean Soc. Environ. Eng., 32(4), 325-332(2010).
  8. Ambulgekar, G. V., Samant, S. D. and Pandit, A. B., "Oxidation of alkylarenes using aqueous potassium permanganate under cavitation: comparison of acoustic and hydrodynamic techniques," Ultrasonics Sonochem., 12(1), 85-90(2005). https://doi.org/10.1016/j.ultsonch.2004.04.005
  9. Wang, X., Wang, J., Guo, P., Guo, W. and Li, G., "Chemical effect of swirling jet-induced cavitation: Degradation of rhodamine B in aqueous solution," Ultrasonics Sonochem., 15(4), 357-363(2008). https://doi.org/10.1016/j.ultsonch.2007.09.008
  10. Wang, X. and Zhang, Y., "Degradation of alachlor in aqueous solution by using hydrodynamic cavitation," J. Hazard. Mater., 161(1), 202-207(2009). https://doi.org/10.1016/j.jhazmat.2008.03.073
  11. Saharan, V. K., Pandit, A. B., Kumar, P. S. and Anandan, S., "Hydrodynamic cavitation as an advanced oxidation technique for the degradation of Acid Red 88 dye," Ind. and Eng. Chem. Res., 51(4), 1981-1989(2012). https://doi.org/10.1021/ie200249k