Comparative Evaluation of Sodium Alginate and Agar Beads for Ammonia and Phosphate Removal in Algae-Based Phycoremediation Systems

This study investigates the efficiency of algal beads synthesised with sodium alginate and agar for the removal of ammonia and phosphate in phycoremediation systems, addressing the persistent issue of nutrient pollution in wastewater.The objectives were to optimise bead formulation, compare pollutant removal performance between agar-and alginate-based matrices, and evaluate the statistical significance of the results.Algal biomass was immobilised in 2% sodium alginate and 2% agar to produce uniform beads, and their nutrient removal efficiency was assessed over a three-day period using spectrophotometric analyses; the salicylate method at 660 nm for ammonia and the molybdate method at 880 nm for phosphate.Statistical analyses were conducted using independent t-tests and one-way ANOVA.The alginate-based beads demonstrated significantly higher removal efficiencies for ammonia (up to 85%) and phosphate (up to 80%) compared with agar-based beads, which achieved approximately 65% and 60%, respectively (p < 0.05).The superior performance of alginate beads is attributed to their enhanced porosity and nutrient diffusion capacity, while agar beads, despite their mechanical stability, exhibited limited nutrient transport and uneven algal distribution.These findings underscore the importance of bead matrix composition in algae-based phycoremediation and identify sodium alginate as a promising encapsulation material for enhancing nutrient removal efficiency in sustainable wastewater treatment applications.