Most industries are now required to treat their wastewater on site before it is discharged to river or sewer (to meet a discharge consent limit), but this treatment will vary depending on the contaminants present. Domestic wastewater will include both sewage and ‘grey’ water, such as outflow from baths and washing machines, and underground pipes will collect the wastewater, which ends up at a centralised urban wastewater treatment works (UWwTW).
Wastewater can be defined as water which is of no further immediate value to the purpose for which it was used or in the pursuit of which it was produced, because of its quality. However, it is possible that wastewater from one producer can be used as a potential supply to another organisation.