Characteristics, treatment techniques, and operational limitations for refinery wastewater: Review

Abstract

Large quantities of wastewater generate from refineries in the process of crude oil usage, distillation, and cooling systems. The wastewater samples need to be treated before disposing into the environment. Disposal of the untreated refinery wastewater causes problems for the water sources and environment. The aim of this work was to study the characteristics, treatment techniques, and limitations of refinery wastewater treatment. A number of tables were prepared to summarize and review wastewater characteristics, treatment process, and the operational limitations. Results revealed that values of some parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), phenols, oil and grease, and total suspended solids (TSS) were 40.25 mg/L to 8,000 mg/L, 80 mg/L to 21,000 mg/L, 3.5 mg/L to 128 mg/L, 12.7 mg/L to 50,000 mg/L, and 22.8 to 2,580 mg/L, respectively. Numerous treatment technologies were used for the treatment of refinery wastewater. Treatment techniques have benefits, weaknesses, and operational limitations. Most amount of the TSS, oil and grease, organic materials are eliminated in the primary and secondary treatment units. Tertiary/Advanced treatment units are necessary for removal of the remaining portions of the contaminants, heavy metals, nitrogen compounds, and phosphorus. Combination of physical, chemical and biological treatment techniques increase removal efficiency of the contaminants.