Development and application of a novel immobilized marine microalgae biofilter system for the treatment of shrimp culture effluent

Removal of excessive nutrients is essential for aquaculture wastewater treatment to protect receiving waters from eutrophication and for potential reuse of the treated water. This semi pilot-scale wastewater treatment system consists of agar-alginate algal blocks (AAAB). It was tested for removal of nutrients in shrimp farm wastewater. Aquaculture wastewater (90 days old Litopenaeus vannamei cultured water) was treated with a novel biofilter that was filled with a marine microalgae Picochlorum maculatum immobilized in alginate blocks. The removal rates of nutrients (phosphate, nitrate, nitrite and ammonia) were evaluated at each cycle for ten cycles. The results showed that the nitrite (89.6%) and ammonia (98.5%) were removed effectively while - phosphate (57%) and nitrate (46.4%) were removed less effectively.