4.1.3 Liquid wastes from industrial areas

In industrial areas liquid wastes are generated by processing or manufacturing industries and service industries, such as car repair shops. The type of industry determines the composition of the waste. The wastewaters from facilities that make food products will not be harmful to humans, but those from other industries may contain a variety of chemical compounds, some of which may be hazardous (and therefore potentially harmful). Industrial wastewaters which contain hazardous substances must be treated, and the substances removed before the wastewater is discharged to the environment. We will consider some specific examples of industrial wastes in Section 4.3.

The presence of hazardous materials is one way in which industrial wastewaters are often different from domestic wastewaters. Another difference is that the flow rate can vary dramatically in some industries, for example, where production rates vary with the season, such as in the processing of certain food crops.