Abstract:
Effluent from aquaculture is high in dissolved inorganic nitrogen and phosphorus.
The effluent should be treated before discharge into the aquatic environment.
Biological treatment by using microalgae is widely used to remove nutrient from
wastewater. The major drawback of this treatment is the difficulties to regulate and
harvest the microalgae from the culture system. Immobilization of microalgae by
using calcium alginate is potential to overcome the problem. Immobilization also
provides a more stable matrix and better protection to the microbe and enhances
nutrient removal. This study aims to improve immobilization of Nannochloropsis sp.
in calcium alginate for removing excessive nutrient from the aquaculture water.
Optimal formulation for immobilizing Nannochloropsis sp. in calcium alginate was
5 % (w/v) alginate solution and hardens by 2 % (w/v) CaCl2 solution. Performance
of the immobilized cell was boosted by addition of nutrient during the process of
immobilization. As compared to the ordinary formulation, growth rate and ammonia
uptake of the nutrient-enriched immobilized cell increased by 67.9 % and 42.7 %,
respectively.
