This article presents the possibility of using the classical Fenton process (Fe(II)/H2O2) to purify synthetic textile wastewater (COD=1872 mg O2/dm3, TOC=660 mg/dm3) containing azo dye Anilan Blue GRL 250% (200 mg/dm3) and Sodium Lauryl Sulphate (SLS) as anionic surfactant at a concentration of 95 mg/dm3. Model studies were carried out using RSM, obtaining a good fit of approximated values to experimental values (R2=0.9461 and R2adj=0.7379). For optimal process parameters (pH 3, Fe(II) 0.85 g/dm3, H2O2 14.5 g/dm3), complete decolourisation (<10 mg Pt/dm3) was achieved as well as a reduction in COD, TOC and SLS concentrations to 83%, 44% and 98%, respectively.