The petrochemical industry is a significant source of hazardous waste, leading to widespread environmental
pollution. For the first time, an integrated approach was employed in the current study to combine life cycle
assessment (LCA) coupled life cycle cost (LCC) analysis with waste sludge disposal scenarios to evaluate trickling
filter (TF), membrane bioreactor-reverse osmosis (MBR-RO), and integrated fixed-film activated sludgemembrane bioreactor (IFAS-MBR) performance at the individual unit level for the treatment of petrochemical
wastewater. The midpoint LCA modeling indicated that the main environmental burdens in the studied systems
were freshwater eutrophication (<5.31 kg P eq) and toxicity potentials (<263.16 kg 1,4-DCB). These impacts
were primarily attributed to the emissions of zinc, copper, nickel, and the processing of heat and gas. Furthermore, the results of the LCC analysis revealed that the TF system was more cost-effective than the MBR-RO and
IFAS-MBR systems. By utilizing the produced biogas for energy provision in the TF system, significant reductions
in toxicity potentials and ecosystem impact categories ranging from 26.72 % to 56.69 % were observed. Additionally, the biowaste scenario exhibited lower environmental concerns (<50 %) compared to incineration or
landfill. In conclusion, this investigation provides valuable perspectives and a sustainable strategy for future
policymaking regarding petrochemical wastewater treatment.