Feasibility of Microalgae Immobilisation in Alginate Bead for Kitchen Wastewater Treatment

Abstract

Microalgae harvesting after wastewater treatment is a critical challenge due to the free-floating nature of cells. This study evaluates the feasibility of immobilising Botryococcus sp. in alginate beads, focusing on bead size stability, compressive strength, and cell retention. Sodium alginate and calcium chloride (CaCl2) were optimised to produce beads with improved mechanical properties and minimal cell leakage. Beads formed with 40 gL–1 alginate and 40 gL–1 CaCl2 demonstrated superior compressive strength and stability. The immobilised microalgae exhibited no cell leakage at low and medium biomass stocking densities. Moreover, the alginate matrix supported microalgae growth, underscoring its potential for sustained wastewater treatment applications. These findings highlight the viability of alginate-immobilised microalgae systems for biomass recovery and reuse.