By-products and wastes generated by the oil and gas industry must be properly managed and treated. Oil-drilling cuttings (ODCs) are the major wastes generated during the process of oil/gas exploration and extraction. ODCsispre-treated in a sonicator by mixing it with synthetic seawater of pre-specified composition at varying volume ratios, with the presence of the anionic surfactant sodium dodecyl sulphate (SDS) at various concentrations (0%, 0.2%, and 0.5%). The pre-treated solution is placed in a poly (methyl methacrylate) (PMMA) column where an ozone-rich gas is bubbled through a porous diffuser. During the ozonation process, a number of parameters (pressure drop, pH, redox-potential, temperature) are monitored on-line, while solid and liquid samples are collected to detect the changes of the total organic carbon (TOC), chemical oxygen demand (COD) and total petroleum hydrocarbons (TPH).