The aim of the research was to determine the possibility of treated dairy wastewater using in the process of microalgae Platymonas subcordiformis biomass production. Researches were conducted in the laboratory scale with vertical photobioreactors using. Experiment was divided on the three variants based on the amount of wastewater introduced to culture medium. The researches proved the tested wastewater can be used in the intensive culture biomass of microalgae Platymonas subcordiformis. The highest technological effects associated with the increase in algal biomass obtained in the control sample where the concentration of algae cells at the end of the expansion process was nearly 3500 mgs.m.o./dm³. In embodiments using waste water as a component of the culture medium obtained microalgae increase over 2000 mgs.m.o./dm³.