Wastewater can contain physical, chemical and biological pollutants. Households may produce wastewater from flush toilets, sinks, dishwashers, washing machines, bath tubs, and showers. ... After treatment at a wastewater treatment plant, treated wastewater (also called effluent) is discharged to a receiving water body.
Wastewater is "used water from any combination of domestic, industrial, commercial or agricultural activities, surface runoff or stormwater, and any sewer inflow or sewer infiltration". Therefore, wastewater is a byproduct of domestic, industrial, commercial or agricultural activities.