STUDY ON BASIC METHODS OF SPENT CAUSTIC TREATMENT

Recently, refinery and petrochemical producer is forced by more stringent environmental regulations to better monitor and control their wastewater. Oneof the key contributors to relatively high chemical oxygen demand (COD) and biological oxygen demand (BOD) is from the acid gas (both CO2 andH2S) and mercaptan removal system(s) typically using dilute caustic soda (NaOH) as the active reagent. The resultant waste stream is otherwiseknown as spent caustic. It’s difficult to treat and dispose of due to its noxious properties. Today’s various methods are used for treating spent caustic,such as wet air oxidation and direct acid neutralization. In this review, these methods were studied in detail and were compared together