Integrated red tilapia aquaculture with Chlorococcum sp. cultivation: Bioremediation of aquaculture wastewater and biomass production

Abstract

The growing need for sustainable aquaculture requires innovative wastewater treatment solutions with environmental and economic benefits. This study examines the use of Chlorococcum sp., a locally isolated microalga, for nutrient removal and biomass production in aquaculture wastewater. Red tilapia (Oreochromis spp.) fingerlings were reared in a 200 L tank over 92 days, with continuous monitoring of water quality parameters. Variations in fish survival rate and feed conversion ratio were influenced by water quality fluctuations. The harvested wastewater was then utilized as a culture medium for Chlorococcum sp. in a flat-plate photobioreactor, achieving high nutrient removal efficiencies—98.7 % total nitrogen (TN), 98.94 % total phosphorus (TP), and 83.58–86.59 % chemical oxygen demand (COD) reduction. Microalgae biomass concentration reached 1.075 g/L (batch 1) and 1.45 g/L (batch 2), with substantial cell growth. Growth kinetics indicated the localy isolated microalgae was resilient in aquaculture wastewater. These findings highlight the potential of Chlorococcum sp. for sustainable wastewater treatment while contributing to biomass valorization. The study provides key insights for optimizing microalgae-based bioremediation in large-scale aquaculture systems.