Harvesting Nannochloris oculata by inorganic electrolyte flocculation: effect of initial cell density, ionic strength, coagulant dosage, and media pH.
Process variables affecting harvesting efficiency of Nannochloris oculata by AlCl(3) flocculation such as, cell density, ionic strength, coagulant dosage, media pH, and cell surface charge were investigated. Initial cell density and coagulant dosage had a significant effect on the removal efficiency; however, levels of ionic strength tested were not significant. Best flocculation conditions of investigated variables were: 0.0016 ng of AlCl(3)/cell, 3.0×10(7) cell/mL, and pH 5.3. Removal efficiency at optimum conditions and salt concentrations of: 0, 15, and 30 g/L NaCl was 96, 98, and 97 %, respectively. Low cell density cultures ∼10(6) cell/mL, required five times greater AlCl(3) dosage to achieve the same removal efficiency. Destabilization of algal cultures using 0.0032 ng of AlCl(3)/cell was observed by reducing the zeta potential to -22 mV. Acidification with HCl for conducting flocculation at pH 5.3 could be a significant cost burden unless is mitigated by selecting a low-buffering-capacity media.
Biological and Agricultural Engineering Department, Texas A&M University, 2117 TAMU, College Station, TX 77843, USA.
Andrea J
AJ
Garzon-Sanabria
Ryan T
RT
Davis
Zivko L
ZL
Nikolov
D002452:Cell Count; D000460:Chlorophyta / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development*; D003470:Culture Media / Q000737:chemistry*; D004573:Electrolytes / Q000494:pharmacology*; D005427:Flocculation / Q000187:drug effects; D005618:Fresh Water; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D009994:Osmolar Concentration; D012965:Sodium Chloride / Q000494:pharmacology; D012984:Software; D055672:Static Electricity
D003470:Culture Media; D004573:Electrolytes; D012965:Sodium Chloride