Quantity of generated wastewater that is treated in a given year and discharged from treatment plants (effluent). Wastewater treatment is the process to render wastewater fit to meet applicable environmental standards for discharge. Three broad phases of traditional treatment can be distinguished: primary, secondary and tertiary treatment. Discharge standards vary significantly from country to country, and therefore so do the phases of treatment. For purposes of calculating the total amount of treated waste water, volumes and loads reported should be shown only under the highest"" type of treatment to which it was subjected. ""