Cascade Aerator

30 Pages·2012·1.1 MB·English

Islamic University of Gaza  ‐Environmental Engineering Department
WWaatteerr TTrreeaattmmeenntt
EENV 4331
Lecture 2:   Aeration
Dr.   Fahid Rabah
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2.1 Purpose of Aeration in water Treatment
AAeerraattiioonn iiss uusseedd ffoorr mmaannyy ppuurrppoosseess iinn wwaatteerr TTrreeaattmmeenntt , tthhee
main uses are:
11.. IInnccrreeaassee tthhee ddiissssoollvveedd ooxxyyggeenn ccoonncceennttrraattiioonn iinn wwaatteerr..
2. Decrease CO concentration thereby reduce its
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ccoorrrroossiivveenneessss..
3. Reduce taste and odor caused by dissolved gases such as
HHyyddrrooggeenn ssuullpphhiiddee ((HH SS)) aanndd mmeetthhaannee ((CCHH )) tthhaatt aarree
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removed during aeration.
44.. OOxxiiddiizzee iirroonn aanndd mmaannggaanneessee ffrroomm tthheeiirr ssoolluubbllee ttoo
insoluble states and cause them to precipitate so that they
maybe removed by sedimentation and filtration processes.
5. Remove certain volatile organic compounds.
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2.2 Types of aerators used in water Treatment
TThhee mmoosstt ccoommmmoonn aaeerraattoorrss uusseedd iinn wwaatteerr ttrreeaattmmeenntt aarree ::
1. Gravity Aerators: In gravity aerators, water is allowed to fall
bbyy ggrraavviittyy ssuucchh tthhaatt aa llaarrggee aarreeaa ooff wwaatteerr iiss eexxppoosseedd ttoo
atmosphere, sometimes aided by turbulence. Cascade
aerators and Multi‐tray aerators are two examples of this
type.
2. Fountain Aerators : These are also known as spray aerators
with special nozzles to produce a fine spray.
3. Injection or Diffused Aerators : It consists of a tank with
perforated pipes, tubes or diffuser plates, fixed at the
bbottttom tto rellease ffiine aiir bbubbbblles ffrom compressor uniitt.
4. Mechanical Aerators : Mixing paddles as in flocculation are
usedd. PPaddddlles may bbe eiitthher subbmergedd or att tthhe surfface.
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CCaassccaaddee AAeerraattoorr
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CCaassccaaddee AAeerraattoorr
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CCaassccaaddee AAeerraattoorr
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Cascade Aerator
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Cascade Aerator
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Cascade Aerator
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Cascade Aerator
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