Microalgae feeds are currently used in relatively small amounts in aquaculture, mainaly for the production of larvae, juvenile and adult fish, as well as for raising the zooplankton required for feeding of juvenile animals. The operating costs for outdoor cultivation of microalgae were LE 34.76/ton live algae in sewage and drainage water. While the oven thy biomass Chlorella vulgaris and Scenedesmus bijuga by cultivated on sewage water were LE 58.15 & 51.87/kg dry biomass respectively but on the drainage water were LE 54.65 & 50.12/kg dry algae, respectively. The microalgae production by wastewater and drainage water can reduce the costs for algae production 14.2% cheaper than by clean processes. In this study the labor cost represented the major count of the total operating costs (46.03%), followed by electricity (20.13%).