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Effects of electric current on electrocoagulation for optimal harvesting of microalgae for advanced wastewater treatment

하수고도처리용 미세조류의 최적회수를 위한 전기응집기술 적용에 있어 전류의 영향

  • Lee, SeokMin (Department of Environmental Engineering, Center for Environmental Studies, Kyung Hee University) ;
  • Joo, Sung Jin (Department of Environmental Engineering, Center for Environmental Studies, Kyung Hee University) ;
  • Choi, Kyoung Jin (Department of Environmental Engineering, Center for Environmental Studies, Kyung Hee University) ;
  • Zhang, Shan (Department of Environmental Engineering, Center for Environmental Studies, Kyung Hee University) ;
  • Hwang, Sun-Jin (Department of Environmental Engineering, Center for Environmental Studies, Kyung Hee University)
  • 이석민 (경희대학교 환경공학과.환경연구센터) ;
  • 주성진 (경희대학교 환경공학과.환경연구센터) ;
  • 최경진 (경희대학교 환경공학과.환경연구센터) ;
  • 장산 (경희대학교 환경공학과.환경연구센터) ;
  • 황선진 (경희대학교 환경공학과.환경연구센터)
  • Received : 2014.07.28
  • Accepted : 2014.08.11
  • Published : 2014.08.15

Abstract

Microalgae is known as one alternative energy source of the fossil fuel with the small size of $5{\sim}50{\mu}m$ and negative charge. Currently, the cost of microalgae recovery process take a large part, about 20 - 30% of total operating cost. Thus, the microalgae recovery method with low cost is needed. In this study, the optimum current for Scenedesmus dimorphus recovery process using electrocoagulation techniques was investigated. Under the electrical current, Al metal in anode electrode is oxidized to oxidation state of $Al^{3+}$. In the cathode electrode, the water electrolysis generated $OH^-$ which combine with $Al^{3+}$ to produce $Al(OH)_3$. This hydroxide acts as a coagulant to harvest microalgae. Before applying in 1.5 L capacity electrocoagulation reactor, Scenedesmus dimorphus was cultured in 20 L cylindrical reactor to concentration of 1 OD. The microalgae recovery efficiency of electrocoagulation reactor was evaluated under different current conditions from 0.1 ~ 0.3 A. The results show that, the fastest and highest recovery efficiency were achieved at the current or 0.3 A, which the highest energy efficiency was achieved at 0.15 A.

Keywords

References

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