Biofloc wastewater for microalgae (Chlorella ellipsoidea) production: an approach to algal biomass production and nutrient remediation

Bold Basal Medium (BBM) is a standard but expensive medium for Chlorella ellipsoidea culture. This study evaluated the effect of biofloc wastewater (BWW) on the growth and pigment content of C. ellipsoidea and also investigated its bioremediation potential. The experiment was conducted for 24 d in five treatments, each with three replications. BBM was replaced with BWW at 0, 25, 50, 75, and 100% levels and considered as control (0% BWW), 25% BWW, 50% BWW, 75% BWW, and 100% BWW treatment, respectively. During the exponential period, the cell dry weight, optical density, cell density, specific growth rate, chlorophyll a, b, and beta-carotene content were significantly (P (<) 0.05) higher in 75% BWW treatment, which was followed by 0% BWW, 50% BWW, 100% BWW, and 25% BWW, correspondingly. NH3, NO2, and PO4 recovery efficiency were also higher in 75% BWW treatment. Therefore, the study proves that 75% BWW has the potential to culture C. ellipsoidea as an alternative to expensive BBM along with nutrient recovery from BWW.