1. Introduction
A large amount of water is used in refinery processes, especially during distillation, hydro-treating, desalination and systemwater cooling,
which means that wastewater from a petroleum refinery is typically characteristic of heavy pollution subsequently running into rivers [1].
It is generally regarded that a light fraction of aliphatic, aromatic petroleum hydrocarbons,
ammonia and halogenated organic substances,
which are the most important contaminants contribute to high chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) value [2].
The traditional treatments of refinery wastewater are based on mechanical and physicochemical methods such as oil–water separation and coagulation followed by biological treatment.
Several solutions have been proposed in this regard,
including the use of chemical coagulation [3,4], biodegradation