Water Treatment Technologies and Their Costs - Global Drinking Water Management and Conservation - page 39

Table 3.3 Treatment Technologies
Technology Description Treatment

class

High rate treatment
and clari cation a

￿ Consists of a clari cation system (Acti o) and
filtration system (Dusen o Mixed Bed Filters)

Class 2

￿ Reduces turbidity, color, suspended solids, algae, taste

and odor (T&O), metals and total organic carbon

￿ The resulting filtered water from the Dusenflo gravity

filter can contain little or no Giardia and Cryptospo-
ridium cysts
￿ MINIMUM PLANT SIZE: 473 m 3 /day

UV System b ￿ Utilizes the ability of ultra violet rays to deactivate

microorganisms

Class 3

￿ This system on its own is chemical free and produces

no disinfection byproducts

￿ However, it can also be used in conjunction with other

treatment processes forming a ”

approach for treating water for drinking purposes
￿ UV will inactivate bacteria, viruses and protozoa,
including Giardia and Cryptosporidium with a dose of
40 mJ/cm 2
￿ We assume some filtration system to remove
sediments (e.g. sand filtration) would be required and
is included in the cost

“ multi-barrier

MINIMUM PLANT SIZE: 200 m 3 /day ￿

MF-UF c ￿ Micro filtration and ultra filtration involves separating

water from organic and inorganic matter contained in
the water by forcing it through a micro porous
membrane

Class 3

￿ Pore sizes in microfiltration membranes are 0.1 to 10
microns thick while ultra filtration membranes are
between 0.001 and 0.1 microns

￿ Microfiltration will remove Giardia and Cryptospori-

dium cysts, bacteria, and some viruses; however not
all viruses can be removed via this process.

￿ Microfiltration is also used in sterilization of bever-

ages and pharmaceuticals, clearing of fruit juices,
wine and beer, separation of oil-water emulsions and
pre-treatment of water for Nano-filtration and reverse
osmosis

￿ Ultra filtration removes all viruses, bacteria and

suspended solids between 0.001 and 0.1 m. Ultra

filtration is used in paint treatment, oil-water emulsion
separations, the food industry and textile industry
￿ MINIMUM PLANT SIZE: 379 m 3 /day

µ

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