As saline industrial wastewater production increases and freshwater resources decline, it is crucial to develop sustainable and cost-effective treatment methods. This study investigated the growth, pigment production, and desalination capacity of the halophilic microalgae Dunaliella salina in brackish wastewater from a power plant (BWW) and modified Johnson medium (MJM) with varying NaCl concentrations (0.5–2.5 M). Synthetic media with controlled salinities were selected for accurate comparison with real wastewater and to evaluate the effect of salinity on growth and metabolite production. The maximum biomass recorded in MJM#0.5 and BWW was 2.14±0.28 g/L and 1.82±0.23 g/L, respectively, and decreased with increasing salinity, reaching 1.68 ± 0.14 g/L in MJM#2.5, indicating the negative impact of high osmotic pressure on cell division and nutrient uptake. Chlorophyll production followed a similar trend, with the highest total chlorophyll (16.9±1.7 mg/L) observed in MJM#0.5. With increasing salinity to moderate levels (MJM#2), ionic stress was induced, leading to enhanced carotenoid and β-carotene production (41.4±4.3 and 37.2±1.2 mg/L, respectively). In BWW, due to nitrogen and phosphate limitation as well as moderate ionic stress, significant accumulation of carotenoids and β-carotene was observed, with values of 30.2±1.8 and 27.9±6.1 mg/L, respectively. Salinity reduction in BWW was substantial, with EC and TDS decreasing by 23.2±2.5% and 52.5±7.5%, respectively. Major ions were effectively removed, including phosphate (90.4 ± 18.8%), total nitrogen (69.5 ± 5.8%), and sulfate (71.7 ± 7.8%). These results demonstrate that D. salina can simultaneously produce valuable metabolites and sustainably treat saline wastewater.