Microalgae have immense potential in remediating toxic content in wastewater and serve as prospective organisms in the treatment of wastewater. Our present study reduces the input cost for microalgae cultivation using wastewater as a growth medium. Scenedesmus rubescens KACC 2, isolated from Siruvani freshwater body (India), was investigated for removal of nitrates, phosphates and heavy metals by growing microalgae in wastewater both as free cells and immobilized algal cells. Among the various polymers used for immobilization, beads with good stability were selected (аlginate and аlginate-сarrageenan) for phycoremediation. Growth and uptake of nutrients in the culture were compared and reduction in the levels of nitrates, phosphates, and heavy metal contents were monitored periodically. Reductions of phosphates (98%) and nitrates (75%) were observed with alginate algal beads. Mn, Zn, and Cu were more reduced by algae beads than with free cells. The study concludes that the immobilized microalga were effective in wastewater treatment, as with free cells, by utilizing nutrients and serve as a cost-effective green technology in biomass generation.

Keywords: microalgae, effluents, phycoremediation, cost-effective medium, immobilization, green technology

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