The use of algae to treat wastewater has been under investigation for decades. Laboratory experiments were performed to study the growth rate and nitrate and phosphate uptake of free and immobilized cells of saline tolerant, nitrogen fixing cyanobacterium Gloeocapsa gelatinosa. The immobilization was carried out in calcium alginate matrix. The immobilized cells were found to be highly effective in the removal of nutrients. 93% of nitrate was absorbed by immobilized cells within 24 hours whereas algae- free beads and free algal cells absorbed only 46% and 70% respectively. 80% of phosphate was also absorbed by immobilized cells within 24 hours. The results suggest that G. gelatinosa is a promising biological agent for nutrient removal from wastewater. Bioreactors with immobilized cells of this alga could be developed for the removal of nutrients from aquatic system.

Gloeocapsa gelatinosa, calcium alginate, immobilization, micro algae, nutrient removal.