Flocculation-based methods of microalgae removal from the eutrophic pond enrichment culture

• Published in: Water science & technology. Water supply 2021-12, Vol.21 (8), p.4254-4262
• Main Authors: Melnikova, Anna A., Komova, Anastasiya V., Vasilev, Ruslan A., Namsaraev, Zorigto B., Gorin, Kirill V.
• Format: Article
• Language: English
• Subjects: Algae; Algal blooms; Aquatic ecosystems; Aquatic microorganisms; ballast; Biomass; Cations; Coagulants; Composite materials; Efficiency; Enrichment media; Eutrophication; Ferric chloride; Flocculants; Flocculation; harvesting of biomass; inorganic coagulants; Laboratories; Methods; Microalgae; Microorganisms; Phosphorus; Phytoplankton; Plankton blooms; Polyacrylamide; Polyethylene; polymeric flocculants; Ponds; Reagents; Sedimentation & deposition; Water depth; Water quality; Water treatment
• ISSN: 1606-9749; 1607-0798
• DOI: 10.2166/ws.2021.174

The method of flocculation of biomass from the water depth to the bottom can be applied in case of local algae blooms. In our research, the combined application of FeCl3 and Polyethyleneoxide-based cationic flocculant was applied for the first time for the harvesting of the enrichment culture obtained from the reservoir during eutrophication. The effects of coagulant (FeCl3·6H2O), various flocculants based on polyacrylamide (PAA), polyethylenoxide (PEO) and flocculated biomass as ballast agent, dosage and sedimental time on flocculation efficiency of harvesting enrichment culture obtained from Pond Chernoistochinsky during eutrophication have been studied. The results show that the flocculation efficiency achieved about 90% after 5 min of sedimentation when adding coagulant and flocculant mixture (FeCl3 30 mg/L + PEO based Sibfloc-718 2.5 mg/L) or flocculant with ballast agent (FeCl3 30 mg/L + Sibfloc-718 2.5 mg/L + 1,7% flocculated biomass). PAA, PEO and FeCl3·6H2O did not demonstrate a sufficient flocculation capacity with enrichment culture containing different types of microalgae.