Performances of solar photocatalytic pilot plant using TiO2-P25 (Degussa) were investigated for removal of commercial azo dye chosen as model compound. Experiments were carried out to optimize various parameters, influencing the performance of the operated thin-film fixed-bed reactor (TFFBR) with an area of 25 m(2). The results showed kinetic dependency on flow rate, catalyst loading, and initial dye concentration. The best discoloration rate was obtained at the optimum flow rate of 3 m(3)/h. Increasing catalyst loading density up to 10 g/m(2), does not lead to high improvement of the discoloration rate. The photocatalytic degradation kinetic of TOC is discussed in terms of Langmuir-Hinshelwood model. Initial mineralization rate expressed by mg kJ(-1) reach a maximum value at initial TOC closed to 30 mg/L.