Wastewater treatment serves one of the critical functions of modern society. Networks of sewers convey wastewater to pump stations and eventually a wastewater treatment plant — also called a water resource recovery facility. The water then passes through a headworks systems to remove large debris and grit before entering a settling tank. The water then passes through primary, secondary and tertiarty treatment steps, which vary plant-by-plant. Activated sludge is among the most common treatment processes used. Read more about wastewater treatment in the articles below.