Water Resources Engineering Civil Engineering ENGC...
Transcript of Water Resources Engineering Civil Engineering ENGC...
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Water Treatment Technology
Water Resources EngineeringCivil Engineering
ENGC 6305
Dr. Fahid Rabah PhD. PE.
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1. Introduction
1.1 Objectives of water treatment• The principal objective of water treatment is to provide
potable water that is chemically and biologically safe for human consumption. It should also be free from unpleasant tastes and odors.
• water treatment objective is to produce both "potable" and "palatable".- Potable: - Water that can be consumed in any desired amount without concern for adverse heath effects. Potable dose not necessarily mean that the water tastes good.- Palatable: - it is a water that is pleasing to drink but not necessarily safe.
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1. Introduction…cont’d
1.1 Objectives of water treatment..Cont’d• Water treatment aims at producing water that satisfies
a set of drinking water quality standards at a reasonable price to the consumers.
• Removal of solids in water. Solids maybe suspended, dissolved or colloidal. Some of the dissolved solids should stay in water at healthy concentrations.
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1.2 Water Quality
1.2.1 Water quality characteristicsa. Physical characteristics:-• Turbidity• Color• Taste and odor• Temperatureb. Chemical characteristics:• Many dissolved chemicals exist in water and many of them are
of concern such as:-Chloride, fluorides, Iron, lead, manganese, sodium, sulfate, zinc, toxic inorganic substances, toxic organic substances,
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1.2 Water Quality
1.2.1 Water quality characteristics.. Cont’dc. Microbiological characteristic:-Pathogens: viruses, bacteria, protozoa, helminthes
(warms)
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1.2 Water Quality
1.2.2 Water quality standards
See the EPA Primary drinking water standards
See the typical composition of water from different sources
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Secondary MCLs (mg/L)
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1.2 Water Quality1.2.3 Water classification by source
Ground- vs. Surface WaterGroundwater
• constant composition• high mineral content• low turbidity• low color• low or no D.O.• high hardness• high Fe, Mn
Surface water• variable composition• low mineral content• high turbidity• colored• D.O. present• low hardness• taste and odor
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1.2 Water Quality
1.2.3 Water classification by source- Surface water- Ground water.
• The difference between the two water types is given in the following table.
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1.3 Water treatment methods1.3.1 Unit operations and Unit processesWater treatment plants utilize many treatmentprocesses to produce water of a desired quality.These processes fall into two broad divisions:-A) Unit operations: (UO)
Removal of contaminants is achieved by physical forces such as gravity and screening.
B) Unit processes (UP)Removal is achieved by chemical and biological reactions.
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1.3 Water treatment methods1.3.2 Most common treatment methods• Coagulation and flocculation (UP)• Softening (UP)• Reverse osmosis RO (UP)• electrodialysis (UP)• ion exchange (UP)• adsorption (UO)• Precipitation (UP)• disinfection (UP)• sedimentation (UO)• filtration (UO
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1.4 Water Treatment Plants
1.4.1 Most common water treatment plantsWater treatment plants can be classified as:-
A) Simple disinfection:-It is a direct pumping and chlorine injection. Used to treat high quality water.
B) Filtration plants: (surface water)• Removes: color, turbidity, taste, odor, and bacteria (filtration
plant)• if the source water has better quality with lower solids,
flocculation and sedimentation can be omitted, this modification is called direct filtration.
C) softening plants:- (ground water)
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Surface Water Treatment
Surface water from supply
Rapid Mix
FlocculationBasin
Sedimentationbasin
SludgeRapid Sand Filter
Disinfection
Storage
To DistributionSystem
Screen
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Groundwater Treatment
Ground waterfrom wells
Sedimentationbasin
SludgeRecarbo-nation
To Distri-butionSystem
Rapid Mix
FlocculationBasin
Disinfection
StorageCO2
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Treatment Flow ChartCapacity: 132 million m3/day
Reservoir
Intake
ChlorineinjectionStabilization
tank
PAC Coagulant
Sedimentationtank
Flashmix
Flocculationtank
Filter
ChlorineinjectionClear wellPump
Finished waterstorage tank
Household
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Conventional Water Treatment Process
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Sedimentation
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Sedimentation Tank
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Circular Clarifiers
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Automatic Backwash Filter
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Filtration
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Flocculator
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Vertical Baffle Flocculator
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Flocculation
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Trojan UV 8000 LP System
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