Simulated textile effluent treatment and biomass production through an integrated ozonation and microalgae process: optimization using response surface methodology.

Ozonation has proven highly effective for treating textile effluents, particularly for dye removal and enhancing biodegradability. However, due to the high costs associated with ozonation, it becomes more efficient when combined with biological processes such as microalgae cultivation. This study investigated an integrated ozonation and microalgae process using Chlorella sorokiniana to treat simulated textile effluent while producing biomass. The key factors considered in this integrated process were ozonation time (OT), microalgae aeration rate (MA), and the proportion of ozonated textile effluent (PE) in the microalgae culture medium. A central composite design (CCD) and response surface methodology (RSM) were employed to assess the significance of factors, their interactions, and to identify the optimal conditions. The integrated approach effectively removed over 96% of ammoniacal nitrogen and 74% of color, with phosphorus removal rates ranging from 57 to 96%. Optimal conditions for maximizing biomass production while meeting environmental discharge standards were identified: 19.30 min for OT, 3 L·min⁻¹ for MA, and 100% for PE. Under these conditions, biomass productivity would achieve 3.18 × 10⁻² g·L⁻¹·day⁻¹, with color and phosphorus removal rates exceeding 94%.