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