Treatment Requirements	Technology Options to Meet Regulatory Requirements	Stage of Acceptability	Comments
Filtration of surface water supplies to control turbidity and microbial contamination	Slow sand filtration	Established	Operationally simple; low operating cost; requires relatively low turbidity source water
	Package plant filtration	Established	Compact; variety of process combinations available
	Ultrafiltration (membranfiltration)	Emerging	Experimental, expensive
	Cartridge filtration	Emerging	Experimental, expensive
Disinfection	Chlorine	Established	Most widely used method; concerns about health effects of by-products
	Ozone	Established	Very effective but requires a secondary disinfectant, usually some form of chlorine
	Ultraviolet radiation	Established	Simple, no established harmful by-products, but requires secondary disinfectant, usually some form of chlorine
Organic contamination control	Granular activated carbon (GAC)	Best Available Technology (BAT)	Highly effective; potential waste disposal issues; expensive
	Packed column aeration	Best Available Technology (BAT)	Highly effective for volatile compounds; potential air emissions issues
	Diffused aeration	Established	Variable removal effectiveness
	Multiple tray aeration	Established	Variable removal effectiveness
	Higee aeration	Experimental	Compact, high energy requirements; potential air emissions issues
	Mechanical aeration	Experimental	Mostly for wastewater treatment; high energy requirements, easy to operate
	Catenary grid	Experimental	Performance data scarce; potential air emissions issues
Inorganic contamination control	Membranes (reverse osmosis and electrodialysis)	Established	Highly effective; expensive; potential waste disposal issues
	Ion exchange	Established	Highly effective; expensive; potential waste disposal issues
	Activated alumina	Established	Highly effective; expensive; potential waste disposal issues
	Coagulation/Filtration	Established	May be difficult for very small systems
	Aeration	Established	Preferred technology for radon removal