ADVANCED WASTEWATER TREATMENT USING MICROALGAE IN NILE TILAPIA (OREOCHROMIS NILOTICUS) AQUACULTURE.

Removal of dissolved inorganic nutrients and heavy metals from wastewater effluent using microalgae is a subject of great interest due to its polytonal stress in aquatic ecosystems. Advanced treatment (ter‌tiary treatment) of wastewater includes the removal of dissolved inor‌ganic nutrients and heavy metals from secondary treated. So, Cider°lia vulgaris and Scenedesmus bijuga microalgae in this study were incubated for six days in secondary treated domestic sewage in an outdoor cultiva‌tion tanks. The results revealed that a complete depletion of ammonium and orthophosphate nutrients occurred with both algae, whereas nitrate up‌take rate was 84% in C vulgaris and 57.7% in S. bijuga. Mineral ele‌ments (Magnesium, Potassium and Sodium) nearly had the same uptake rate for both algae. Uptake rates of heavy metals (Fe, Zn, Cu, Pb & Ni) in Chfovea experimental tank was higher than that of Scenedesmus tank. On contrary, Mn heavy metal uptake rate by Chlore4a was lower (80%) than its uptake rate (100%) by Scenedesmus Further study on using of sewage grown CAloretkt and Scenedes-mus with high protein content 46.5% & 52.7%, respectively in fish feed‌ing was conducted. There were no great differences in weight gain and specific growth rate of the experimented tilapia fishes at different nutri‌tional regime. The highest protein content (67.5%) occurred in fishes fed with Scenedesmus biomass grown in sewage and supplemented with 2% artificial fish food regime. The results indicated that, cultivation of Chktretia vulgaris and Scenedesmus bijuga in secondary treated sewage effluent can be used as an advanced sewage treatment to remove inorganic N, reduce pollu‌tion problems, and to produce algal protein useful in fish feeding.