The purpose of this research is to co-culture microalgae and yeast in secondary treated wastewater in a bioreactor. Wastewater will be characterized via measuring pH, turbidity, COD, ammonia, nitrate, orthophosphate, conductivity, and total suspended solids, before and after microalgae and yeast cultivation to monitor the efficiency of the wastewater treatment process. For harvesting biomass an ozonation/ozoflotation process will be used with the variation in the flow rate, ozonation time and ozone concentration to optimize the process. This research will empirically investigate the effect of cell disruption of microalgae using ozoflotation. Furthermore, the research aims to find the optimum harvesting approach by combining ozoflotation with other techniques. All the experiments will be done multiple times in order to achieve accurate results. This research aims to combine the separation of microalgae and harvesting of lipid in the same process to reduce the energy demand. Also, it aims to quantify the cell rupture of microalgae by ozonation.