Industrial processes and operations use a large amount of water, however only a small amount of that water may be used or incorporated into the final product. The majority of the water is expelled as wastewater and may contain numerous pollutants. Before this wastewater is discharged into the environment, steps must be taken to ensure that any pollutants present are at safe levels.

Industrial wastewater treatment methods depend on the elements present in the wastewater at the end of the process or activity. Industrial wastes can be processed by the methods used at municipal treatment plants. However where the effluent may need special treatment to prevent polluting the environment, industries are required to treat the harmful component of the waste. Some industries are required to develop their own treatment plants to manage the specific type of wastewater generated at their facility.

There are numerous treatment methods depending on the content of the effluent for example:

Oils and grease can be skimmed from the surface of the effluent; however, where oils and grease have dissolved into the liquid effluent removing them can be very difficult.

Metals can either be removed by changing the pH or through chemical treatment, however, if this does not work the metal contained in the effluent needs to be concentrated and recycled.

Acids and Alkalis need to be neutralised before being released into the environment.

Effluent or coolant temperature must be reduced before it can be safely released into the aquatic environment. This can be achieved by dilution or by evaporative cooling.