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III. Water TreatmentTopic III.3. Water Precipitation: Processes and

FacilitiesPrecipitation Processes

Precipitation of spherical mineral particles in batch settler

(Stockes)

Precipitation of natural particles (with arbitrary shapes and dimensions) in batch settler

Relationship between percentage of the settled particles - and time of settling - t

Relationship between percentage of the settled particles - and settling velocity - u0

Precipitation of natural particles in continuous flow settling tanks with mean horizontal flow velocity - v and real settling velocity - u

; ;

2...18

1dgu

w

wp

0

0

00 .

30

. uv

u

uuu

0.ukv )(

L

Hfk

2

Precipitation Processes

= f(t) = f(u0)

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Precipitation Processes

Scheme of Horizontal Continuous Settling Tankv - mean horizontal flow velocity; u0 - vertical precipitation velocity at batch conditions; w -

vertical component of pulse (arbitrary flow) velocity;

u - real settling velocity

, where F is the water mirror area, m2

, where k = 7,5 with L/H = 10; k = 10 with L/H = 15; k = 12 with L/H = 20

,where W is volume the setter, m3

0.6,3

.

u

QF

0.ukv

uHQtQW .6,3/..

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Kinds of Settling Tanks

Scheme of Horizontal Settling Tank1 - coarse water; 2 - sediments cleaning device; channel for floating particles removal;

5 - sludge removal pipe

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Kinds of Settling Tanks

Vertical Settling Tank

a - without flocculation chamber

б - with built-in flocculation chamber

1 - coarse water

2 - settled water

3 - sludge removal

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Kinds of Settling Tanks

Radial Settling Tank1 - coarse water; 2 - sludge circulation; 3 - stilling chamber; 4 - settling zone; 5 - sludge

cleaner; 6 - sludge; 7 - settled water; 8 - mixer; 9 - reagents inlet pipe

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Kinds of Settling Tanks

Scheme of Lamella Settling Tank

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Kinds of Settling Tanks

Lamella Settling Tank

Prefabricated lamella settler Lamella modules