The present work aims to evaluate the potential for bioremediation and CO2 fixation by cultivating the microalgae of the genus Chlorella minutissima in cassava wastewater. Experimental work investigated the growth of microalgae in the effluent and determined its growth rate based on different dilutions. Four culture media scenarios were created. The values measured in the laboratory were compared with a mathematical model adjusted based on the kinetic growth. The efficiency of the process was evaluated in terms of the reduction of the organic load, nutrient consumption, and cell count in the initial state (time 0) and complete growth (after the seventh day) using microscopy analysis. After biological treatment, a percentage of reduction of COD (chemical oxygen demand) of around 30%, TS (total solids) 75%, nutrient removal 92%, cyanide near 99%, and average CO2 biofixation 0.19 g L−1 d−1 were observed. The reduction percentages are close to those found in the literature for other cultivation media. It was observed in this study that the biomass productivity and CO2 fixation agree with those obtained in other studies and confirm the efficiency of the very tiny Chlorella microalgae with high photosynthetic capacity.