Surface Water Treatment Plant

Fig 4-8: Flow Diagram of conventional surface water treatment plant (“filtration plant”)

Coagulation = Charge reductionFlocculation = Contact of particles

Fig 4-10: Effect of salt on electric potential

Fig 4-11: Effect of valence on electric potential

Fig 4-8: Flow diagram of water softening plant

Alkalinity in Coagulation

Needed to neutralize acid formed

Fig 4-13: results from jar test

Paddle Mixer Details

Paddle Mixers in Left Chamber and Flocculators in Right Two Chambers

Fig 4-35: Settling in an upflow clarifier

Fig 4-32: Zones of sedimentation on a horizontal flow clarifier

Q

V

h

time

depthvs

Q

V

h

time

depthvs

V

hQ

QVh

vs

wlhhQ

vs

os vA

Qv

Fig 4-37: Partial solids removal in ideal sedimentation tank

Fig 4-37: Partial solids removal in ideal sedimentation tank

o

s

v

vP 100

Let’s say v0 = 0.20 mm/s

What % removal for particles with settlingvelocity = 0.15 mm/s?

%7520.0

15.0100 P

Fig 4-43: Typical gravity filter box

Fig 4-44: Operation of rapid sand filter

Manual Control Panel in Water Treatment Plant

Lime slaker and feed system.

Upflow solids contact tank. Effluent weir on right.

Settling tank with radial weirs

Rapid sand filter with exposed under drain block.Wash water troughs run from left into gullet on right.

Rapid sand filter with water level just below backwash troughs. Note iron stain at high water line.

Rapid sand filter during filtration.Reflection shows water level above gullet and backwash troughs.

Rotameter used to measure flowrate of gaseous chlorine into water.

Hydrofluorosilicic acid drum and pump metering system for feeding fluoride into water.

Softening sludge lagoon. Winter view shows ice (light blue) where supernatant water is stnading.

Overview of water treatment plant showing sludge lagoons and building housing treatment facilities.