탁도제거를 위한 미세공기 부양법 연구

Studies of Micro-Air Flotation for Removal of Turbidity

  • Choi, Boram (Department of environmental engineering, Pukyong National University) ;
  • Kim, Dongsoo (Department of marine bio-materials and aquaculture, Pukyong National University) ;
  • Kim, Jongoh (Department of civil engineering, Gangneung-Wonju National University) ;
  • Kim, Taeyoon (Department of environmental engineering, Pukyong National University)
  • 발행 : 2013.08.01

초록

본 연구에서는 해수담수화의 효율을 높이기 위한 효율적인 전처리 기법을 찾기 위해 응집제 투입과 같이 마이크로 공기를 주입하여 전처리 효율을 측정하였다. $AlCl_3{\cdot}6H_2O$와 PGA 응집제 주입량에 따른 탁도 제거효율을 알아보았다. 탁도 유발 물질은 해저퇴적토와 해양미세조류를 선정하여 실험에 필요한 탁도를 구현하였다. 퇴적토 함유 인공해수는 $AlCl_3{\cdot}6H_2O$ 0.5g/L 주입 시 제거율 73.7%를 얻은 반면 PGA 경우 0.05g/L 주입만으로 92.4% 제거율을 얻었다. 미세조류 함유 인공해수 또한 PGA 응집제 0.05g/L의 주입 만으로 95% 이상의 높은 제거효율을 보였다. 퇴적토를 함유 인공 해수에 비해 미세조류를 함유한 인공해수에서 효율이 더 좋았으며, 두 경우 모두 0.1g/L의 PGA 응집제 투입 후 1분간의 응집과정을 거친 후 마이크로 공기를 5초간 주입하였을 때 최적의 제거효율을 보여주었다. 마이크로 공기 주입 후 약 10분 후 최고의 탁도 제거율에 도달하였다. 본 연구결과를 통해 높은 탁도를 가진 해수일지라도 응집제와 마이크로 공기를 주입할 시 신속히 제거가 되었으므로, 본 연구결과는 해수 전처리에 효과적으로 사용될 수 있을 것으로 판단된다.

In this study, efficiency of pre-treatment of turbid seawater was measured where micro-air bubbles were used to remove particles in seawater after input of natural coagulant PGA. Artificial seawater was prepared having the intended trubidity using marine sediments and microalgae. 73.7% of turbidity removal was achieved when 0.5g/L of $AlCl_3{\cdot}6H_2O$ was added in the artificial seawater, but 92.4% of turbidity removal was observed when 0.05g/L of PGA was added in the artificial seawater containing microalgae. In addition, much greater turbidity removal was achieved for microalage than sediments. For both cases, input of 0.1g/L PGA and following additional input of micro-air bubbles for 5 seconds resulted in the maximum removal efficiency where reaction time of coagulation was 1 min and flotation by micro-air bubbles was 10 min. From this study, we concluded that micro-air floation after coagulation could be a possible economical pre-treatment method for highly turbid seawater.

키워드

참고문헌

  1. Agarwal, A., Ng, W. J. and Liu, Y.(2011), Principle and applications of microbubble and nanobubble technology for water treatment, Chemosphere, Vol. 84, No. 8, pp. 1175-1180. https://doi.org/10.1016/j.chemosphere.2011.05.054
  2. Altaher, H.(2012), The use of chitosan as a coagulant in the pre-treatment of turbid sea water, J. Hazard. Mat., Vol. 233-234, No. 2, pp. 97-102. https://doi.org/10.1016/j.jhazmat.2012.06.061
  3. Annadurai, G., Sung, S. S. and Lee, D. J.(2004), Simultaneous removal of trubidity and humic acid from high turbidity strom water, Adv. Environ. Res., Vol. 8, No. 3, pp. 713-725. https://doi.org/10.1016/S1093-0191(03)00043-1
  4. Chu, L. B., Xing, X. H., Yu, A. F., Zhou, Y. N., Sun, X. L. and Jurcik, B.(2007), Enhanced ozonation of simulated dyestuff wastewater by microbubbles, Chemosphere, Vol. 68, No. 12, pp. 1854-1860. https://doi.org/10.1016/j.chemosphere.2007.03.014
  5. Chu, L. B., Xing, X. H., Yu, A. F., Sun, X. L. and Jurcik, B.(2008a), Enhanced treatment of practical textile wastewater by microbubble ozonation, Process Safety and Environ. Protection, Vol. 86, No. 2, pp. 389-393. https://doi.org/10.1016/j.psep.2008.02.005
  6. Chu, L. B., Yan, S. T., Xing, X. H., Yu, A. F., Sun, X. L. and Jurcik, B.(2008b), Enhanced sludge solubilization by microbubble ozonation, Chemosphere, Vol. 72, No. 3, pp. 205 -212. https://doi.org/10.1016/j.chemosphere.2008.01.054
  7. Dincer, S. R., Karakaya, N., Gunes, E. and Gunes, Y.(2008), Removal of COD from oil recover industry wastewater by the advanced oxidation process (AOP) based on $H_2O_2$, Globe NEST J., Vol. 10, No. 1, pp. 31-38.
  8. Kilic, M. Y., Kestioglu, K. and Yonar, T.(2007), Landfill leachate treatment by the combination of physicochemical methods with adsorption process, J. Biol. Environ. Sci., Vol. 1, No. 1, pp. 37-43.
  9. Konig, E. H. and Van Der Merwe, I. W.(2000), Applying ultrafiltration as polishing process in direct water reclamation, Proceedings of the Water Institute of Southern Africa (WISA), Sun City, pp. 127-128.
  10. Li, P., Takahashi, M. and Chiba, K.(2009), Enhanced free-radical generation by shrinking microbubbles using a copper catalyst, Chemosphere, Vol. 77, No. 12, pp. 1157-1160. https://doi.org/10.1016/j.chemosphere.2009.07.062
  11. Liu, S., Wang, Q. H., Ma, H. Z., Huang, P. K., Li, J. and Kikuchi, T.(2010), Effect of micro-bubbles on coagulation flotation process of dyeing wastewater, Separation and Purification Technol., Vol. 71, No, 6, pp. 337-346. https://doi.org/10.1016/j.seppur.2009.12.021
  12. Takahashi, M., Kawamura, T., Yamamoto, Y., Ohnari, H., Himuro, S. and Shakutsui, H.(2003), Effect of shrinking microbubble on gas hydrate formation, J. Physic. Chem., Vol. B 107, No. 10, pp. 2171-2173.
  13. Takahashi, M.(2005), ${\zeta}$ potential of microbubbles in aqueous solutions: electrical properties of the gas-water interface, J. Physic. Chem., Vol. B 109, No. 11, pp. 21858-21864.
  14. Takahashi, M., Chiba, K. and Li. P.(2007), Free-radical generation from collapsing microbubbles in the absence of a dynamic stimulus, J. Physic. Chem., Vol. B 111, No. 8, pp. 1343-1347.
  15. Yang, H. J. and Kim, H. S.(2009), Effect of coagulation on MF/UF for removal of particles as a pretreatment in sea water desalination, Desalination, Vol. 249, No. 7, pp. 42-52.
  16. Yang, C.(2002), Observation of microbubble attachment onto a hydrophilic glass surface, Chemical Engr. Sci., Vol. 57, No. 11, pp. 1485-1488. https://doi.org/10.1016/S0009-2509(02)00016-7
  17. Zhidong, L., Na, Z., Honglin, Z. and Dan, L.(2009), Studies and applications processes on flocculants in water treatment in China, Electron. J. Geotech. Eng., Vol. 14, No. 1, pp. 1-7.