Explain the Surface Water Treatment Methods

A. Physical Unit Operations

• change in water quality is brought about through the application of physical forces
• screening, mixing, gas transfer, sedimentation, filtration,...etc.

B. Chemical Unit Operations

• Removal or treatment of contaminants is brought about by the addition of chemicals or chemical reactions
• precipitation, disinfection, coagulation, oxidation, ion exchange

C. Biological Unit Operations

• Removal of contaminants is brought about by biological means
• used only for wastewater treatment and not for water treatment
• activated sludge, trickling filter, oxidation ponds, lagoons....etc.

D. These processes are usually combined in most treatment systems