Water Quality Improves by Recycling Settled Sludge

Wastewater operators are responsible for the biological processes of an activated sludge plant where, at the beginning of the treatment process, settled activated seed sludge is inoculated in incoming raw sewage flow to kick‐start the growth of bioreducing organisms in the sewage. This article describes how this same process of recirculation works equally well in the flocculation and coagulation processes of drinking water treatment. Recycling fresh, settled chemical floc back to the incoming raw water flow initiates formation of good‐quality chemical floc with exceptionally good solids and impurities removal and settling and filtering characteristics, particularly during coldwater seasons. This practice also provides many labor and cost‐saving advantages.