Korean Journal of Environmental Biology (환경생물)

Korean Society of Environmental Biology (한국환경생물학회)
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Development of Economic Culture System Using Wastewater for Microalgae in Winter Season

폐수를 이용한 겨울철 경제적 미세조류 배양 시스템의 개발

  • Lee, Sang-Ah (Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB)) ;
  • Lee, Changsoo (Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB)) ;
  • Lee, Seung-Hoon (Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB)) ;
  • An, Kwang-Guk (Department of Biological Science, School of Biological Sciences and Biotechnology, Chungnam National University) ;
  • Oh, Hee-Mock (Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB)) ;
  • Kim, Hee-Sik (Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB)) ;
  • Ahn, Chi-Yong (Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB))
  • 이상아 (한국생명공학연구원 환경바이오연구센터) ;
  • 이창수 (한국생명공학연구원 환경바이오연구센터) ;
  • 이승훈 (한국생명공학연구원 환경바이오연구센터) ;
  • 안광국 (충남대학교 시스템생명과학부) ;
  • 오희목 (한국생명공학연구원 환경바이오연구센터) ;
  • 김희식 (한국생명공학연구원 환경바이오연구센터) ;
  • 안치용 (한국생명공학연구원 환경바이오연구센터)
  • Received : 2013.08.27
  • Accepted : 2014.03.03
  • Published : 2014.03.31
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Abstract

The outdoor mass cultivation is not possible for microalgae in Korea all year round, due to cold winter season. It is not easy to maintain proper level of productivity of microalgae even in winter. To prevent a drastic decrease of temperature in a greenhouse, two layers were covered additionally, inside the original plastic layer of the greenhouse. The middle layer was made up of plastic and the inner layer, of non-woven fabric. Acrylic transparent bioreactors were constructed to get more sunlight, not only from the upper side but also from the lateral and bottom directions. In winter at freezing temperatures, six different culture conditions were compared in the triply covered, insulated greenhouse. Wastewater after anaerobic digestion was used for the cultivation of microalgae to minimize the production cost. Water temperature in the bioreactors remained above $10^{\circ}C$ on average, even without any external heating system, proving that the triple-layered greenhouse is effective in keeping heat. Algal biomass reached to 0.37g $L^{-1}$ with the highest temperature, in the experimental group of light-reflection board at the bottom, with nitrogen and phosphorus removal rate of 92% and 99%, respectively. When fatty acid composition was analyzed using gas-chromatography, linoleate (C18 : 3n3) occupied the highest proportion up to 61%, in the all experiment groups. Chemical oxygen demand (COD), however, did not decrease during the cultivation, but rather increased. Although the algal biomass productivity was not comparable to warm seasons, it was possible to maintain water temperature for algae cultivation even in the coldest season, at the minimum cost.

우리나라는 겨울철에 미세조류가 성장하기에 적합하지 않은 기후조건을 가진다. 따라서, 차세대 바이오매스의 공급원료로서의 미세조류 배양을 겨울철에 이룩하기는 쉽지 않다. 본 연구에서는 적은 에너지를 이용하여 미세조류가 성장이 불가한 영외환경에서 미세조류를 성장시키기 위해서, 삼중막의 비닐하우스를 설치하였다. 또한 투명한 아크릴 재질로 수조를 제작하여 빛을 수조의 모든 면에서 받을 수 있게 함으로써, 빛의 이용성을 최대화하였다. 6가지의 다양한 실험조건을 설정하여 겨울철 영하의 기후조건에서 최소한의 비용으로 하수종말처리장 폐수를 사용하여 미세조류를 배양하였다. 또한 미세조류 바이오매스를 증가시킴과 동시에 환경오염의 원인이 될 수 있는 영양염류 성분 중 질소를 최대 92%, 인을 최대 99%까지 제거시켰다. 본 연구에서 바이오디젤의 원료가 될 수 있는 가장 주된 지방산은 리놀렌산(C18 : 3n3)으로 총 지질량의 최대 61%까지 차지했다. 지방산의 생산성은 2.4 g $m^{-2}day^{-1}$이었다. 결론적으로, 본 연구를 통하여 차세대 바이오매스 생산을 위한 미세조류 배양을 저온 시기에서도 이룩하였으며, 그에 따른 폐수처리에서도 좋은 성과를 이루었다.

Keywords

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