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2.10 CHAPTER TWO

TABLE 2.4 Most Common Drinking Water Treatment Processes

Water quality parameter Process components
Turbidity-particulate reduction Filtration
• Rapid sand---conventional
Coagulation
Flocculation
• Clarification
Plain settling
Plate settlers
Solids contact
Dissolved air flotation
Filtration
• Rapid sand--direct mode
Coagulationlflocculation
Filtration
Slow sand filtration
• Diatomaceous earth filtration
• Membrane filtration
Ultrafiltration
Nanofiltration
Reverse osmosis
Bacteria, viruses, cyst removal Partial reduction--filtration (above)
Inactivation---disinfection
• Chlorine
• Chloramine
• Chlorine dioxide
• Ozone
• UV
Color Coagulation/rapid sand filtration
Adsorption
• Granular activated carbon (GAC) media
• Powdered activated carbon (PAC) addition
• Synthetic resins (ion exchange)
Oxidation
• Ozone
• Chlorine
• Potassium permanganate
• Chlorine dioxide
Nanofiltration
Taste and color control Oxidation
• Ozone
• Chlorine
• Chlorine dioxide
• Potassium permanganate
BAC adsorption
Volatile organic reduction Air stripping
• GAC adsorption
• Combination of the above
Disinfection by-product control Precursor reduction
• Enhanced coagulation
• GAC adsorption
• Biologically activated carbon (BAC) media--
preozonation
• Nanofiltration