A packed-bed (PBR), fiber (FR), membrane (MR), and tubular (TR) photocatalytic reactor have been modeled to compare their performance on a pilot scale. The influence of radial dispersion in the PBR and mass-transfer limitation in the PBR, FR, and TR has been taken into account. The oxygen concentration in the liquid has a large influence on the performance and, therefore, air or pure oxygen should be added. The MR and PBR have a better performance than the TR and FR. Only a small degree of mass-transfer limitation occurs in the PBR. Radial dispersion hardly influences the performance of the PBR. External mass-transfer limitation influences the conversion in the TR and FR severely. The PBR, MR, and TR show a much better energy efficiency than the FR.