Biotechnology Letters

, Volume 40, Issue 4, pp 697–702 | Cite as

Harvesting Chlorella vulgaris via rapid sedimentation induced by combined coagulants and tapered shear

  • Haiyang Zhang
  • Yang Ou
  • Ting Chen
  • Lan Yang
  • Zicheng Hu
Original Research Paper



In this study, a rapid sedimentation induced by combined coagulants and gradual shear was developed to harvest Chlorella vulgaris.


The microalgal harvesting efficiency was observably promoted by the synergistic effect between FeCl3 and PAM, especially in the first 10 min. A higher harvesting efficiency, 95.61%, could be achieved within approximately 3 min due to the large and dense flocs generated by the combined coagulants. In contrast, the efficiencies were only 54.25 and 60.20% with FeCl3 and PAM, independently. When coagulation was performed under gradually reduced shear (from 50 to 30 rpm), smaller clusters or cells filled the pores of the aggregates via interception, which caused the flocs to become larger and more compact.


The sedimentation time was shortened to 30 s for microalgal coagulation induced by the simultaneous use of combined coagulants and tapered shear, providing an effective approach to harvesting microalgae.


Chlorella vulgaris Coagulation Combined coagulants Gradual shear Microalgae harvesting Sedimentation 



The authors gratefully acknowledge the support of the Doctor Research Foundation of Southwest University of Science and Technology (14zx7130) and Foundation of Key Laboratory of Solid Waste Treatment and Resource Recycle Ministry of Education for Professional Innovation Research Team (14tdgk02).


  1. Alam MA et al (2014) Characterization of the flocculating agent from the spontaneously flocculating microalga Chlorella vulgaris JSC-7. J Biosci Bioeng 118:29–33. CrossRefPubMedGoogle Scholar
  2. Alhattab M, Brooks MS-L (2017) Dispersed air flotation and foam fractionation for the recovery of microalgae in the production of biodiesel. Sep Sci Technol 52:2002–2016. CrossRefGoogle Scholar
  3. Barros AI, Gonçalves AL, Simões M, Pires JCM (2015) Harvesting techniques applied to microalgae: a review. Renew Sustain Energy Rev 41:1489–1500. CrossRefGoogle Scholar
  4. Bo X, Gao B, Peng N, Wang Y, Yue Q, Zhao Y (2011) Coagulation performance and floc properties of compound bioflocculant-aluminum sulfate dual-coagulant in treating kaolin-humic acid solution. Chem Eng J 173:400–406. CrossRefGoogle Scholar
  5. Chang TJ (1998) Simplified settling velocity formula for sediment particle—discussion. J Hydraul Eng-Asce 124:653–654. CrossRefGoogle Scholar
  6. Demirbas A (2010) Use of algae as biofuel sources. Energy Convers Manag 51:2738–2749. CrossRefGoogle Scholar
  7. Godos ID, Guzman HO, Soto R, García-Encina PA, Eloy Becares, Muñoz Raúl AVV (2011) Coagulation/flocculation-based removal of algal-bacterial biomass from piggery wastewater treatment. Bioresour Technol 102:923–927. CrossRefPubMedGoogle Scholar
  8. Gorin KV et al (2015) Methods coagulation/flocculation and flocculation with ballast agent for effective harvesting of microalgae. Bioresour Technol 193:178–184. CrossRefPubMedGoogle Scholar
  9. He WP, Nan J, Li HY, Li SN (2012) Characteristic analysis on temporal evolution of floc size and structure in low-shear flow. Water Res 46:509–520. CrossRefPubMedGoogle Scholar
  10. Ho YC, Norli I, Alkarkhi AFM, Morad N (2010) Characterization of biopolymeric flocculant (pectin) and organic synthetic flocculant (PAM): a comparative study on treatment and optimization in kaolin suspension. Bioresour Technol 101:1166–1174. CrossRefPubMedGoogle Scholar
  11. Huang G, Chen F, Wei D, Zhang X, Chen G (2010) Biodiesel production by microalgal biotechnology. Appl Energy 87:38–46. CrossRefGoogle Scholar
  12. Kim J, Ryu BG, Kim BK, Han JI, Yang JW (2012) Continuous microalgae recovery using electrolysis with polarity exchange. Bioresour Technol 111:268–275. CrossRefPubMedGoogle Scholar
  13. Laamanen CA, Ross GM, Scott JA (2016) Flotation harvesting of microalgae. Renew Sustain Energy Rev 58:75–86. CrossRefGoogle Scholar
  14. Maggi F, Mietta F, Winterwerp JC (2007) Effect of variable fractal dimension on the floc size distribution of suspended cohesive sediment. J Hydrol 343:43–55. CrossRefGoogle Scholar
  15. Ofori P, Nguyen AV, Firth B, McNally C, Ozdemir O (2011) Shear-induced floc structure changes for enhanced dewatering of coal preparation plant tailings. Chem Eng J 172:914–923. CrossRefGoogle Scholar
  16. Oliveira C, Rodrigues RT, Rubio J (2010) A new technique for characterizing aerated flocs in a flocculation–microbubble flotation system. Int J Miner Process 96:36–44. CrossRefGoogle Scholar
  17. Smith BT, Davis RH (2012) Sedimentation of algae flocculated using naturally-available, magnesium-based flocculants. Algal Res 1:32–39. CrossRefGoogle Scholar
  18. Sun CZ et al (2011) Effect of pH and shear force on flocs characteristics for humic acid removal using polyferric aluminum chloride–organic polymer dual-coagulants. Desalination 281:243–247. CrossRefGoogle Scholar
  19. Teixeira MR, Rosa MJ (2007) Comparing dissolved air flotation and conventional sedimentation to remove cyanobacterial cells of Microcystis aeruginosa: Part II. The effect of water background organics. Sep Purif Technol 53:126–134. CrossRefGoogle Scholar
  20. Turchiuli C, Fargues C (2004) Influence of structural properties of alum and ferric flocs on sludge dewaterability. Chem Eng J 103:123–131. CrossRefGoogle Scholar
  21. Vahedi A, Gorczyca B (2011) Application of fractal dimensions to study the structure of flocs formed in lime softening process. Water Res 45:545–556. CrossRefPubMedGoogle Scholar
  22. Vandamme D, Foubert I, Muylaert K (2013) Flocculation as a low-cost method for harvesting microalgae for bulk biomass production. Trends Biotechnol 31:233–239. CrossRefPubMedGoogle Scholar
  23. Wang DS, Wu RB, Jiang YZ, Chow CWK (2011a) Characterization of floc structure and strength: role of changing shear rates under various coagulation mechanisms. Colloids Surf A 379:36–42. CrossRefGoogle Scholar
  24. Wang YH, Sg Zhou, Li N, Yang Y (2011b) Influences of various aluminum coagulants on algae floc structure, strength and flotation effect. Procedia Environ Sci 8:75–80. CrossRefGoogle Scholar
  25. Wang SK, Stiles AR, Guo C, Liu CZ (2015) Harvesting microalgae by magnetic separation: a review. Algal Res 9:178–185. CrossRefGoogle Scholar
  26. Wong SS, Teng TT, Ahmad AL, Zuhairi A, Najafpour G (2006) Treatment of pulp and paper mill wastewater by polyacrylamide (PAM) in polymer induced flocculation. J Hazard Mater 135:378–388. CrossRefPubMedGoogle Scholar
  27. Wu C-D, Xu X-J, Liang J-L, Wang Q, Dong Q, Liang W-L (2011) Enhanced coagulation for treating slightly polluted algae-containing surface water combining polyaluminum chloride (PAC) with diatomite. Desalination 279:140–145. CrossRefGoogle Scholar
  28. Zhang X, Wang L, Sommerfeld M, Hu Q (2016) Harvesting microalgal biomass using magnesium coagulation-dissolved air flotation. Biomass Bioenergy 93:43–49. CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  • Haiyang Zhang
    • 1
  • Yang Ou
    • 1
  • Ting Chen
    • 1
  • Lan Yang
    • 1
  • Zicheng Hu
    • 1
  1. 1.Key Laboratory of Solid Waste Treatment and Resource Recycle Ministry of EducationSouthwest University of Science and TechnologyMianyangChina

Personalised recommendations