Abstract: The embodiments herein relate to a photocatalytic reactor system and photo-degrading method for eliminating organic and high molecular oil contaminant (or pollutants) from industrial wastewater. A more economical and stable titanium dioxide (TiO2) having a diameter of 21±10 nm is used as the photocatalyst. Method and system of present invention is highly efficient, compatibles with the environment and does not require secondary or additional treatments. In one embodiment, an optimal and very low catalyst concentration (100 ppm) is used for high degradation of the pollutant which is irradiated for utmost 120 min using UV light. This has an industrially interest as this method is considered as an alternative or synergetic process for biological degradation, having high residence times, required to provide significant COD removal. The analysis of the contained materials showed that the efficiency of the applied degradation system is high for all the identified present organic pollutants.