Water Quality Engineering: Physical/Chemical Treatment Processes

Abstract

This chapter deals with the explanation of chemical treatment. The use of chemicals in the treatment of municipal wastewater has increased with the degree of pollution because of the disposal of insufficiently pre-treated industrial wastewater into the municipal wastewater sewerage system. Colloidal solids and very finely divided suspended matter can be removed to a greater or less degree from wastewater only if they are rendered settleable by the addition of coagulants. These are chemical dispersing in water as fine particles loaded with positive electric charge neutralizing the electric field of the natural solid particles in colloidal suspension. Because of this phenomenon, the colloidal suspensions crowd together to form flocs those become larger and larger because of the flocculation. The chapter also explains the theory of chemical precipitation and its efficiency. © 1985, Oedituha Tehnică.