Advanced Treatment Strategies for Spent Caustic Wastewater: A Comprehensive Study

Abstract

Spent caustic is a highly alkaline and toxic wastewater stream generated in petroleum refining and petrochemical industries, primarily from
LPG, naphtha, and ethylene treating units, containing high concentrations of sulphides, mercaptans, and phenolic compounds. Conventional
treatment methods such as steam stripping, wet air oxidation, and neutralization suffer from limitations including high energy consumption
and incomplete pollutant removal. Advanced oxidation processes (AOPs), particularly hydrogen peroxide (H₂O₂)-based systems, have gained
attention due to their ability to generate hydroxyl radicals capable of degrading refractory organic compounds. These methods demonstrate
improved efficiency and environmental performance compared to conventional techniques.