**8. Conclusion**

One of the problems of today's world is the pollution of underground water sources due to the pollutants imported from various industries, especially refineries. These harmful particles enter the water in different ways and pollute the water.

The volume of production effluents is increasing, and there are many petroleum substances in these effluents. Due to the fact that these hydrocarbons are difficult to decompose biochemically and cause damage and destruction to the environment, they must be purified before being discharged into the environment.

Therefore, due to the harmful risks that they cause to human health, the environment, plants, and aquatic organisms, the treatment of petroleum effluents has been given a lot of attention. In addition, due to the large volume of petroleum effluents, a method that can be easily performed, is economically viable, and is able to separate oil pollution with high efficiency is very important.

A specific separation method should be used for each type of industrial waste according to the physical nature of the oil waste. These petrochemical effluents are mainly in the form of oil-in-water emulsions; as a result, breaking emulsions and separating oil require a correct understanding of their physical properties and chemical composition. The choice of each of the methods depends on the economic conditions and the type and form of the oily pollutant in the water. Petroleum wastewater management is done based on the type of pollutant and its volume. Choosing the right treatment method depends on many variables (pollutant type, wastewater volume, pollutant concentration, ability to recycle and extract valuable materials, local energy sources). For example, if the wastewater volume is small and sunlight is available, solar evaporation is the best choice.
