Growing wastewater microalgae contrib-utes to the elimination of nutrients present in wastewater because they need N and P for the synthesis of proteins, nucleic acid, and phos-pholipids. The most sustainable approach for achieving high biomass and high lipid build-up, along with environmental protection. In the current research, nine microalgae were culti-vated on two variations of wastewater (agricul-tural and industrial dyes) and compared to the synthetic medium. The results indicated that after three weeks of the incubation period, the ability of microalgae to grow in sterilized (syn-thetic medium and wastewater) and gave greater biomass and chlorophyll (a) than in non-sterilized ones. Out of the tested nine mi-croalgae, four microalgae (Anabaena oryzae, Spirulina platensis, Anabaena sp (2) and Nos-toc sp) were selected which gave the highest significant values of dry weight, biomass productivity and chlorophyll (a) content. The selected microalgae showed the highest signif-icant values of the chemical composition, i.e., total carbohydrate, protein and lipid when cul-tivated in agricultural wastewater more than those cultivated in both industrial dye’s wastewater and synthetic broth medium. Among four microalgae, two microalgae of A. oryzae HSSASE6 (KT277789), and S. platen-sis NIES-39 (A00800) were chosen where the chemical composition contents ranged from 1.17 to 1.21-fold and 1.03 to 1.06-fold of car-bohydrate, 1.06 to 1.09-fold and 1.88 to 1.93-fold of protein and 1.41 to 1.52-fold and 1.76 to 1.90-fold of lipid more than those of other microalgae, respectively. The agriculture wastewater was inoculated with a single cul-ture of A. oryzae HSSASE6 (KT277789) or S. platensis NIES-39 (A00800) individually with 10 % of inoculum size, which more preferred than was inoculated with consortia culture. Re-sults also showed that A. oryzae HSSASE6 (KT277789) was more efficient strain for giv-ing biomass and productivity in agricultural wastewater than S. platensis NIES-39 (A00800) (about 28% more).

The study was carried out  at  Faculty of Agriculture, Ain Shams University to assess the effect of two of algae species (Arthrospira platensis and Nannochloropsis gaditana) on growth performance of monosex  tilapia fish (Oreochromis niloticus), fish were fed on a basal diet supplemented with 0,3,5,7% of each algae. To perform seven experimental treatments were assigned in three replicates each. The experiment was designated as follows:  (T1) control (without algae), (T2) basal diet supplemented with 3% spirulina (spiru 3), (T3) basal diet supplemented with 5% spirulina (spiru 5), (T4) basal diet supplemented with 7% spirulina (spiru 7), (T5) basal diet supplemented with 3% Nannochloropsis (nanno 3), (T6) basal diet supplemented with 5% Nannochloropsis (nanno 5) and (T7) basal diet supplemented with 7% Nannochloropsis  (nanno 7). Experimental tanks were a part of closed recirculating system, where almost constant environmental conditions were kept throughout the experimental period. Twenty-one quadrate fiber glass tanks with 108-liter water capacity were stocked with 15 fish per tank. The individual initial body weight (2.7 g) was recorded at the beginning of the experiment. All fish in each tank was weighed every two weeks during the whole experimental period. The fish were fed the experimental diet for 95 days Results indicated that nanno 5 treatment had higher significant trend (P<0.05) final body weight (FBW), average weight  gain (AWG) and average daily gain (ADG) compared with the other experimental treatments. The best specific growth rate (SGR), feed conversion ratio (FCR) and feed efficiency ratio (FER) were found in nanno 7. Also, it was observed that spiru 7 have a high significant difference (P<0.05) in protein efficiency ratio (PER) and protein productive value (PPV). On the other hand, the results showed that the lowest AWG, ADG and (FER) appeared in spiru 7%. No mortality in nanno7 and spiru 7. Finally, using of nano 5% or spiru 7% enhance growth performance and feeding in tilapia fish.

This study was carried out to evaluate the efficiency of mixed algal cultures for wastewater treatment. Free and alginate-immobilized forms of mixed algal culture were used. The highest removal percentages of biological oxygen demand (BOD) were 86.4% and 71.2 % after 32hrs and 48 hrs. in case of free and immobilized cells, respectively. Moreover, the highest values of chemical oxygen demand (COD) removal were 83.74% and 59.71% after 32hrs and 48 hrs for free and immobilized cells, respectively. Treatment with free cells showed removal values for total dissolved salts (TDS), phosphorus and NH3-N were 20.5%, 34.6% and 43.8% respectively after 32 hours. While in case of immobilized cells the highest removal values 18.4%, 34% and 58.5%, for TDS, Phosphorus and NH3-N, respectively were recorded after 48 hrs. Generally, concentration of heavy metals decreased due to treatment with algal free and immobilized cells. As a result of treatment with algal free and immobilized cells, 100% and 95.9% of Cu wastewater content was removed after 8 hrs and 48 hrs, respectively. Moreover, 96.2% and 98.1% of Fe was removed after 32 and 48 hours due to application of free and immobilized cells, respectively. As a result of inoculation with the mixed algal cultures in free cells 99.4% of Mn and 84.2% of Zn content were removed after 32 hours. Whereas, 98.6% of Pb content was removed after only 8 hrs. In case of using the immobilized cells the highest removal percentages of the three heavy metals recorded after 48 hours as follow 97.8% of Mn, 89.0% of Pb and 97.37% of Zn. Accordingly, treatment of wastewater with mixed algal free or immobilized cells is a fruitful method to produce an effluent of high quality to be used for irrigation. Whereas, the algal free cells were found to be more efficient than the immobilized ones.