N-methyldiethanolamine (N-MDEA) is used in the natural gas refinery process to remove carbon dioxide (CO2) and hydrogen sulphide (H2S) and was discharged as pollutants with other aromatic hydrocarbons such as Benzene-Toluene-Xylene (BTX) compounds. The small leakage of this component will contaminate the environment and lead to heavy water pollution. These dangerous materials that polluted the water system can effect the aquatic life by consume dissolved oxygen. Thus, some effort must be carried out to overcome these problems. In this study, photocatalytic process has been introduced for the treatment of these compounds using coupled ZnO/TiO2, WO3/TiO2 and ternary ZnO/WO3/TiO2 which were prepared via sol-gel method. The parameters studied in this research were ratio of photocatalyst used, the effect of sonication and ozonation processes, various initial concentrations of substrate and different UV wavelength for the degradation of N-MDEA and BTX compounds in aqueous system. This research should help and provide a new insight to the scientist worldwide in waste water treatment or anyone else who may be considering utilizing this techniques for green environmental efforts.