Effect of Light/dark Cycles on Wastewater Treatments by Microalgae

  • Lee, Kwangyong (Institute of Industrial Biotechnology, Department of Biological Engineering, Inha University) ;
  • Lee, Choul-Gyun (Institute of Industrial Biotechnology, Department of Biological Engineering, Inha University)
  • Published : 2001.05.01

Abstract

Chlorella kessleri cultivated in artificial wastewater using diurnal illumination of 12h light/12h dark (L/D) cycles. The inoculum density was 10(sup)5 cells/mL and the irradiance in light cycle was 45$\mu$mol㎡s(sup)-1 at the culture surface. As a control culture, another set of flasks was cultivated under continuous illumination. Regardless of the illumination scheme, the total organic carbon (TOC) and chemical oxygen demand (COD) was reduced below 20% of the initial concentration within a day. However, cell concentration under the L/D lighting scheme was lower tan that under the continuous illuminating scheme. Thus the specific removal rate of organic carbon under L/D cycles was higher than that under continuous illumination. This result suggested that C. kessleri grew chemoorganotrophically in the dark periods. After 3 days, nitrate was reduced to 136.5 and 154.1mg NO$_3$-N/L from 168.1mg NO$_3$-N/L under continuous illumination and under diurnal cycles, respectively. These results indicate nitrate removal efficiency under continuous light was better than that under diurnal cycles. High-density algal cultures using optimized photobioreactors with diurnal cycles will save energy and improve organic carbon sources removal.

Keywords

References

  1. Nature Prod.Rep. v.3 Marine matural products Faulkner D.J.
  2. Fuel Energy Abstracts Jan v.25 Spiral tubular bioreactor for hydrogen production by photosynthetic microorganisms: Desing and operation ` Markov S.A.;P.F.Weaver;M.Seibert
  3. Bioscience v.46 Algal diversity and commercial algal products Radmer R.J.
  4. J.Biotechnol. v.70 commercial production of microalgae: Ponds,tanks and fermenters Borowitzka M.A.
  5. Wat.Sci.Tech. v.35 Organic wastewater treatment without greenhouse gas emission by photosynthetic bacteria Nakajima F.;N.Kamiko;K.Yamamoto
  6. J.Ferment.Bioeng. v.86 Improvement of microalgal NOx removal in bubble column and airlift reactors Nagase H.;K.Eguchi;K.Yoshihara;K.Hirata;K.Miyamoto
  7. Energy Convers.Mgmt. v.36 CO₂fixation by artificial weathering of waste concrete and coccolithophorid algae cultures Takano H.;T.Matsunaga
  8. J.Ferment.Bioeng. v.81 Carbon dioxide fixation in batch culture of Chlorella sp.using a photobioreactor with a sunlight-collection device Hirata S.;M.Hayashitani;M.Taya;S.Tone
  9. Energy Convers.Mgmt. v.38 The biolobical CO₂fixation and utilization project by RITE(2) Murakami M.;M.Ikenouchi
  10. Appl.Biochem.Biotechnol. v.73 Carbon dioxide fixation and polyunsaturated fatty acid production by the red alga porphyridium cruentum Akimoto M.;A.Shirai;K.Ohtaguchi;K.Koide
  11. Energy v.22 CO₂fixation and ethanol production with microalgal photosynthesis and intracellular anaerobic fermentation Hirano A.;R.Ueda;S.Hirayama;Y.Ogushi
  12. Wat.Sci.Technol. v.38 Toxicity identification evaluation of ammonia, nitrite and heavy metals at the Stensund wastewater aquaculture plant Adamsson M.;G.Dave;L.Forsberg;B.Guterstam
  13. Resour.Conservation Recycling v.11 Influence of organic-N sources on an algal wastewater treatment system Lau P.S.;N.F.Y.Tam;Y.S.Wong
  14. Water.Res. v.32 The relative importance of Lemma gibba L., bacteria and algae for the nitrogen and phosphorus removal in duckweed-covered domestic wastewater Korner S.;J.E.Vermaat
  15. Water.Res. v.31 Wastewater nutrient removal by marine microalgae grown on a corrugated raceway Craggs R.J.;P.J.McAuley;V.J.Smith
  16. Handbook of Microalgal Mass Culture Laboratory Techniques for the Cultivation of Microalgae Vonshak A.;A.Fichmond(ed.)
  17. Standard Methods for the Examination of Water and Wastewater(20th ed.) APHA;AWWA;WEF
  18. Microalgae: Biotechnology and Microbiology Culture Media Becker E.W.
  19. Microalgal Biotechnology Chlorella Oh-Hama T.;S.Miyachi;M.A.Borowitzka;L.J.Borowitzka(eds.)