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Impact of varying nitrate (NO3-N) and phosphate (PO4-P) concentrations and sewage water (SW) on the growth, nutrient removal, lipid accumulation, enzymatic antioxidant activity and phytochemical contents of the microalgae Scenedesmus dimorphus, Coelastrella tenuitheca, Chroococcus turgidus and Parachlorella kessleri under monoculture and their consortia have been investigated. High growth rates were observed for all the four algae in both mono and mixed culture conditions at enhanced concentrations of N (1500 mg/L NO3-N) and P (40 mg/L PO4-P). The species Scenedesmus dimorphus outperformed other microalgae growing in SW in efficiently removing nitrogen. The algal consortia of mixed species was found to be more effective in phosphorus removal. The carbohydrate and protein contents were highest in Parachlorella kessleri, about 37% and 44%, respectively, in SW cultivation. The algal consortia demonstrated highest starch content (4%) in nitrogen deprived growth medium. Highest lipid production (43%) was observed in the SW culture. The species Coelastrella tenuitheca, Chroococcus turgidus and Scenedesmus dimorphus irrespective of the growth media indicated significant accumulation of phenol, flavonoid and tannin. The DPPH, catalase and ascorbic peroxidase assay showed pronounced antioxidant activity. Nutrient (N and P) enrichment exhibited enhanced antioxidant enzymatic activity and accumulation of cell storage products. NOVELTY STATEMENT: This study explores the response mechanisms and nutrient removal capabilities of various microalgal species and their consortia in sewage water treated media. The results provide valuable insights into the potential role of algae in wastewater treatment processes, revealing high tolerance and considerable NO3-N and PO4-P removal capabilities of Scenedesmus dimorphus and algal consortia toward different wastewaters. The results of the study are relevant for the development of sustainable solutions for water pollution management. The algae and their consortia grown in wastewater showed high levels of carbohydrates, proteins, lipids, bioactive compounds accumulation and antioxidant activity rendering them a sustainable and renewable resource for various industrial applications. [ABSTRACT FROM AUTHOR]