Our main purpose was to study the disinfection of a secondary wastewater anaerobic effluent by a combined photolytic-photocatalytic continuous reactor using solar irradiation. This reactor had a rectangular section and included back-and-forth-flow internal channels. It comprised two compartments: the first one corresponded to photolytic disinfection with a residence time and the second one corresponded to photocatalytic disinfection with a residence time. The photocatalyst used was Degussa P-25 fixed on an ordinary tile. By use of this reactor between and with a water flow rate of , the total coliform concentration diminished by four orders of magnitude, reaching values lower than (most probable number)/, which are below the regulation. Even if photolysis was important, this single process did not permit one to obtain an outlet coliform concentration below ; however, it helped to improve the photocatalytic performance. A decrease in chemical oxygen demand (COD) was also observed in the photocatalytic compartment, illustrating an oxidation of organic pollutants. In parallel, batch experiments were carried out to get information about the residence times, the photocatalytic performance of fixed on an ordinary tile, and the photolytic effect. The results suggest that this low cost and easy to operate treatment system could be a promising alternative to usual systems for the decrease in COD and the disinfection of domestic wastewaters.