The winery wastewaters (WW) are characterized by their acidic pH, due to the presence of organic acids and phenolic compounds. Additionally, they contains ethanol, sugars, and other organic compounds that contribute to their high pollutant load. These characteristics make them a significant environmental challenge, requiring specific treatments to reduce its toxicity and enable sustainable utilization. This study proposes a pre-treatment process based on air bubbling and the addition of fly ash from a biomass power plant, with the aim of using the treated wastewater as a culture medium for the growth of microalgae (Chlorella vulgaris). The results obtained showed that the pre-treatment is effective in neutralizing acidity, eliminating ethanol, and reducing the organic load present in the WW, making the medium suitable for microalgae cultivation. Elimination of ethanol by aeration of the raw WW can be achieved after 4 days and the pH was corrected to values close to neutrality by adding fly ash at a concentration of 15 g/L. Only a fraction of the added ash is dissolved in the WW therefore a precipitated ash fraction is also recovered for alternative applications. This study highlights the feasibility of transforming waste into valuable resources through innovative and sustainable approaches.