Sitra Muhaba Yimam creator author. text my 2023 2023 monographic eng xiv, 174 pages : illustrations ; 30 cm. + 1 CD-ROM Petrochemical industries produce a huge amount of wastewater during the production of various petrochemical products. The generated wastewater is required to properly treated before being released into the environment because it contains harmful chemical compounds to human health, the aquatic ecosystem and the environment. However, studies on the lifecycle assessment of petrochemical wastewater treatment processes on energy recovery are rare. Thus, this study aims to investigate the environmental impacts of petrochemical wastewater treatment for the production of methane and hydrogen and make comparisons of environmental impacts for the cases when the two different treatment methods which means the existing method and the new method (Multistage contact oxidation and Photo-reforming) are used for the methane and hydrogen productions in the tertiary treatment stage. For the site data collection, the Petrochemical wastewater treatment plant (PWWTP) which is one of the petrochemical companies available in the Gebeng Industrial Estate, Kuantan was selected as a primary data source. Secondary data from literature and databases of LCA assessment software was obtained. The methodology adapted in this study is of a qualitative method and for the data collection the question form was sent to the treatment plant. Moreover, the collected data was analysed by using a life cycle assessment (LCA) technique which is a widely applied and ISO-guided approach was implemented. The software used for the analysis was GaBi 9.2.1. The GWP contribution by the Ex-PWWTP wastewater line was 6 and 57 times higher than those contributed by electricity generation and chemical production, respectively. This can be significantly reduced if the methane gas is collected and reused as source of energy for the treatment plant. Furthermore, changing the energy mix for electricity generation from fossil fuel to renewable energy can reduce the environmental impacts significantly. Overall, the least environmental impact was registered for the case where the photoreforming technology was implemented and the methane gas produced from the anaerobic digestion was reused. Therefore, it is recommended to use (implement) the photoreforming technology integrated with energy recovery equipment for the petrochemical wastewater treatment process at the Gebeng area treatment plant. specialized Sitra Muhaba Yimam Faculty of Industrial Management Thesis (Master of Science) -- Universiti Malaysia Pahang – 2023 Includes bibliographical references Faculty of Industrial Management Dissertations Universities and colleges Dissertations THE0009830 (Local) UMPSA 240419 20251125110847.0 eng