What is wastewater treatment, and why is it so gross?

Water in sanitary sewers is pretty disgusting. The water going into a sanitary sewer comes from houses, businesses, and factories--and that includes toilet water. So we’re talking big-time gross.

This gunky water is called “wastewater.” But don’t worry. Wastewater is cleaned up at a “wastewater treatment” plant before it ever gets into our rivers.

wastewater treatment

During wastewater treatment, water is separated from “sludge”--the solid gunk in wastewater. This is done in the round “clarifiers” shown here.

Photo: City of Redmond, Oregon