Pretreatment plant

2

PRESENTATIOPRESENTATIONN

KURIEMAT POWER STATION I KURIEMAT POWER STATION I

WATER PRE WATER PRE TREATMENTTREATMENT

AT MOL (SHJ) – JUL. 2007AT MOL (SHJ) – JUL. 2007

FORFOR

PART OF OPERATION TRAININGPART OF OPERATION TRAININGUPPER EGYPT ELECTRICTY PROD CO. & EGYPTIAN UPPER EGYPT ELECTRICTY PROD CO. & EGYPTIAN

ELECTRICITY HOLDING COMPANYELECTRICITY HOLDING COMPANY

4

RAW WATER TREATMENTRAW WATER TREATMENT

WATER WATER CHEMISTRYCHEMISTRY

5

WHAT IS WATER?WHAT IS WATER?COLOURLESS, ODOURLESS, TASTELESS LIQUIDCOLOURLESS, ODOURLESS, TASTELESS LIQUIDPOLAR LIQUIDPOLAR LIQUIDHIGH DIELECTRIC CONSTANT (81 @ 17°C)HIGH DIELECTRIC CONSTANT (81 @ 17°C)EXTREMELY GOOD SOLVENT POWEREXTREMELY GOOD SOLVENT POWERWEAK ELECTROLYTEWEAK ELECTROLYTEDENSITY OF 1.00 @ 4°CDENSITY OF 1.00 @ 4°CALLOTROPIC FORMS: ICE(SOLID) & STEAM(GASALLOTROPIC FORMS: ICE(SOLID) & STEAM(GAS))

RAW WATER TREATMENT - WATER RAW WATER TREATMENT - WATER CHEMISTRYCHEMISTRY

6

Chemical FormulaChemical Formula

H2OH+ OH-

(H2O)n

HOH


7

The Water Molecule

HHO

104°


8

• TWO HYDROGEN ATOMS, 104deg APARTTWO HYDROGEN ATOMS, 104deg APART• DIPOLAR - POSITIVE CHARGE ON DIPOLAR - POSITIVE CHARGE ON

HYDROGEN. NEGATIVE CHARGE ON OXYGENHYDROGEN. NEGATIVE CHARGE ON OXYGEN• DUE TO HYDROGEN BOND HAS HIGH DUE TO HYDROGEN BOND HAS HIGH

ENERGY CONTENTENERGY CONTENT• HYDROGEN BOND CAUSES ICE TO EXPAND HYDROGEN BOND CAUSES ICE TO EXPAND

& CREATES SURFACE TENSION.& CREATES SURFACE TENSION.

WATER COMPOSITIONWATER COMPOSITION• WATER FORMULA = HWATER FORMULA = H2200


9

The Water cycleThe Water cycleNatural SystemNatural System


10

WATER IMPURITIESWATER IMPURITIES

–1 SUSPENDED SOLIDS1 SUSPENDED SOLIDS–22 DISSOLVED SOLIDS DISSOLVED SOLIDS–33 DISSOLVED GASES DISSOLVED GASES


11

SUSPENDED SOLIDS: SUSPENDED SOLIDS: COMPOSITIONCOMPOSITION• LARGE PARTICLES – GRIT, SAND, ORGANICS

LARGER THAN 1 MICRON

• SMALL PARTICLES - TURBIDITY DUE TO CLAY, SAND, SILT, ORGANICS ETC. 0.5 TO 1 MICRON

• COLLIODAL PARTICLES - GENERALLY OF SILICA LESS THAN 1 MICRON


12

SUSPENDED SOLIDS:SUSPENDED SOLIDS: EFFECTS EFFECTS RAW WATER TREATMENTRAW WATER TREATMENT

• SOLIDS PRESENT IN PROCESS USE CREATE VARIETY OF PROBLEMS.

• FOULING OF ION EXCHANGE RESINS & RO.

• DEPOSITS IN HEAT EXCHANGER TUBES AFFECTING HEAT TRANSFER & CAUSING CORROSION.

• POTENTIAL FOR RADIATION EXPOSURE IN NUCLEAR SECONDARY SYSTEMS

• INCREASED BOILER & COOLING TOWER BLOWDOWN

13


TREATMENT OF TREATMENT OF WATER WATER

IMPURITIESIMPURITIES

14


RAW WATER TREAT MENT MAINLY COMPRISE OF REMOVAL OF SUSPENDED SOLIDS, COLOR, BIOLOGICAL CONTAMINATION, ETC.

15

MAIN PROCESSES:MAIN PROCESSES:RAW WATER TREATMENTRAW WATER TREATMENT

• CLARIFICATION

– SETTLE OUT THOSE LARGER SUSPENDED PARTICLES THAT ARE READILY SETTLEABLE.

– CONDITION SMALLER MAKING THEM FILTERABLE

• FILTRATION

• SLUDGE HANDLING

• DISINFECTION

16

REMOVAL OF SUSPENDED SOLIDS:REMOVAL OF SUSPENDED SOLIDS:


• LARGE PARTICLES– THESE CAN BE SETTLED IN SEDIMENTATION

BASINS IN THE FORM OF RESERVOIR OR TANK.

• SMALL PARTICLES– REMOVAL OF SMALL PARTICLES REQUIRE

CLARIFICATION EQUIPMENT.

17


COAGULATICOAGULATIONON

18

CLARIFYING SYSTEM: CLARIFYING SYSTEM: COAGULATIONCOAGULATION


• THE KEY TO CLARIFICATION IS THE ADDITION OF CHEMICALS TO AGGLOMERATE SMALL SUSPENDED SOLIDS SHORTENING THEIR SETTLEMENT TIME.

• THE PRIMARY FACTOR IS ELECTRICAL CHARGE. ALL PARTICLES OF TURBIDITY & COLOR HAVE USUALLY NEGATIVE ELECTRICAL SURFACE CHARGE.

19

CLARIFYING SYSTEM: CLARIFYING SYSTEM: COAGULATIONCOAGULATIONRAW WATER TREATMENTRAW WATER TREATMENT

• THE SIGN OF PARTICLE ELECTRICAL CHARGE & MAGNITUDE ARE AFFECTED BY THE pH & IONIC CONTENT OF THE SURROUNDING WATER.

• THIS (-VE ) CHARGE ATTRACTS A COMPACT LAYER OF OPPOSITE CHARGED IONS (COUNTER IONS) IN A VERY CLOSE FORM & MORE DIFFUSE LAYER FURTHER AWAY.

• THE ABOVE LAYER COMBINATION CREATES ELECTROSTATIC POTENTIAL THAT REPELS OTHER SIMILAR CHARGED PARTICLES.

22


• CHEMICALS CALLED COAGULANTS ARE ADDED TO BREAKDOWN THIS BARRIER BY INTRODUCING OPPOSITE (+VE) .

• COAGULANTS ARE METALLIC SALTS THAT INTRODUCE +VE METAL IONS CARRYING TWO OR MORE ELECTRICAL CHARGES.

• THIS INCREASES THE CONCENTRATION OF COUNTER IONS IN THE DIFFUSE LAYER THUS THE REPULSIVE FORCE IS REMOVED THAT ALLOWS THE PARTICLES TO COME IN CONTACT.

23

CLARIFYING SYSTEM:CLARIFYING SYSTEM: COAGULATION COAGULATIONRAW WATER TREATMENTRAW WATER TREATMENT

• ALUM (ALUMIMIUM SULPHATE IS THE MOST WIDELY USED COAGULANT)

• IN ADDITION TO NEUTRALIZING THE ELECTROSTATIC BARRIER THEY REACT WITH ALAKLINITY OF THE WATER TO FORM A TOUGH ALUMINIUM HYDROXIDE “FLOC” WHICH IS STABLE OVER pH RANGE 5.7-7.5.

• IRON SALTS LIKE FeCl3 PRECIPTATE HYDROXIDE FLOC OVER MUCH BROADER RANGE 5 TO 11 HENCE ARE USEFUL IN LIME SOFTENING PLANTS.

25


• ALUM HYDROLIZING REACTION RELEASES SULPHURIC ACID THAT REACTS WITH ALKALINTY FORMING CaSO4 & CO2.

• EACH ppm OF ALUM USED BRINGS DOWN THE ALKALINITY BY 0.45 ppm. THUS TO COUNTERACT THIS EFFECT 0.4 ppm OF LIME (90% CaO) PER ppm OF ALUM IS ADDED OR 0.5 ppm OF SODA ASH PER ppm OF ALUM.

26


• SODIUM ALUMINATE IS SLIGHTLY ALKALINE. USEFUL TO ADD WITH LOW Ph WATERS REDUCING THE CONSUMPTION OF LIME NEEDED FOR SOFTENING.

• THE QUANTITY OF ANY COAGULANT IS ACTUALLY IS CLOSELY CONTROLLED TO GIVE THE OPTIMUM pH FOR BEST COAGULATION.

27

RAW WATER TREATMENTRAW WATER TREATMENT• OPTIMUM DOSAGE OF CHEMICALS VARY WITH

– SUSPENDED PARTICLE SIZE & CONCENTRATION

– DETENTION TIME BEFORE COAGULATION

– WATER TEMPERATURE

– AMOUNT OF MIXING ETC.

• IN VIEW OF THE ABOVE IT IS EXTREMLY DIFFICULT TO PREDICT THE DOSAGES.

• IN PRACTICE IT IS BASED ON JAR TESTS ON THE WATER IN USE.

CLARIFYING SYSTEM:- COAGULATIONCLARIFYING SYSTEM:- COAGULATION

28

CLARIFYING SYSTEM:- COAGULATIONCLARIFYING SYSTEM:- COAGULATIONRAW WATER TREATMENTRAW WATER TREATMENT

• JAR TEST SHOULD BE RUN AT LEAST ONCE IN A MONTH OR WHENEVER THERE IS APPRCIABLE CHANGE IN WATER QUALITY.

• AS GUIDE, THE UPPER 100 mm IN A SAMPLE SHOULD BECOME CLEAR IN 2-4 MINUTES.

• WATER WITH LOW TURBIDITY MAY BE MORE DIFFICULT TO COAGULATE THAN THAT WITH HIGH TURBIDITY.

29

CLARIFYING SYSTEM:- COAGULATIONCLARIFYING SYSTEM:- COAGULATIONRAW WATER TREATMENTRAW WATER TREATMENT

………….…………..

…………..

…………..

………….

………….…………..…………..………….………….…………..

…………..

…………..

…………..…………..

………….

………….………….

………….…………..………….…………..………….…………..…………..………….…………. …………..………….…………..………….…………..…………..…………..………….………….………….

JAR TEST

Test Beakers

Drive Motor

30

RAW WATER TREATMENTRAW WATER TREATMENTCOAGULANT COAGULANT

AIDS AIDS USE OF USE OF

POLYMERSPOLYMERS

31

CLARIFYING SYSTEM: CLARIFYING SYSTEM: USE OF POLYMERSUSE OF POLYMERSRAW WATER TREATMENTRAW WATER TREATMENT

• POLYMERS ARE USED TO ENHANCE COAGULATION BY GROWING FLOC SIZE.

• THESE ARE POLYELCTROLYTES – SYNTHETIC ORGANIC POLYMERS OF HIGH MOLECULAR WEIGHTS CONTAINING CHEMICALS GROUPS THAT CAN INTERACT WITH SURFACE SITES ON COLLOIDAL PARTICLES.

• THESE ACT WITH EXTREMELY HIGH SPEED ENLARGING THE FLOC SIZE THUS IMPROVING SETTLEMENT.

32

CLARIFYING SYSTEM: CLARIFYING SYSTEM: USE OF POLYMERSUSE OF POLYMERSRAW WATER TREATMENTRAW WATER TREATMENT

• POLYMERS ARE EITHER CATIONIC (+veLY CHARGED) OR ANIONIC (-veLY CHARGED) OR NONIONIC.

• SLIGHTLY ANIONIC POLYMER ARE NORMALLY EFFECTIVE. ONCE AGAIN JAR TEST IS NEEDED TO MAKE THE BEST CHOICE.

• SOMETIMES FOR LESS TURBID WATERS A CATIONIC POLYMER MAY ACT AS PRIMARY COAGULANT.

33

CLARIFYING SYSTEM: CLARIFYING SYSTEM: FLOCCULATIONFLOCCULATIONRAW WATER TREATMENTRAW WATER TREATMENT

• FLOCCULATION IS SLOW STIRRING OF COAGULATED PARTICLES TO ENHANCE THE PARTICLE GROWTH

• NORMAL RETENTION TIMES ARE 20 TO 30 MINUTES

• FLOCCULATING TANKS CAN BE EXTERNAL OR INSIDE CLARIFIER

34

Particle in suspension

Polymer molecule

Agglommerated solids

RAW WATER TREATMENTRAW WATER TREATMENTPOLYMER AID ACTION

35


CLARIFYINGCLARIFYINGEQUIPMENTEQUIPMENT

36

CLARIFYING SYSTEM: CLARIFYING SYSTEM: CLARIFYING EQUIPMENTCLARIFYING EQUIPMENTTHERE ARE NUMBER OF TYPES AND SHAPESTHERE ARE NUMBER OF TYPES AND SHAPESA FEW MOST COMMONLY USED ARE:A FEW MOST COMMONLY USED ARE:


• CONVENTIONAL

• SOLIDS CONTACT

• SOILDS RECIRCULATION

• TUBE SETTLLER

• LEMELLA PLATE

37

CLARIFYING SYSTEM: CLARIFYING SYSTEM: TYPICAL SURFACE LOADING RATES (mTYPICAL SURFACE LOADING RATES (m33/h/m/h/m22))


• CONVENTIONAL 1.2 -1.5

• SOLIDS CONTACT *2.5

• SOILDS RECIRCULATION* 2.5

• TUBE SETTLLER1.8

• LEMELLA PLATE (PROJECTED AREA)1.8

* RELATIVE TO SETTLING TANK SURFACE AREA

38

CLARIFYING SYSTEM: CLARIFYING SYSTEM: TYPICAL SURFACE LOADING RATES (mTYPICAL SURFACE LOADING RATES (m33/h/m/h/m22))


• CONVENTIONAL 1.2 -1.5

• SOLIDS CONTACT *2.5

• SOILDS RECIRCULATION* 2.5

• TUBE SETTLLER1.8

• LEMELLA PLATE (PROJECTED AREA)1.8

* RELATIVE TO SETTLING TANK SURFACE AREA

44


SOLIDS SOLIDS CONTACT/RECIRCULCONTACT/RECIRCULATING CLARIFIERSATING CLARIFIERS

45

CLARIFYING SYSTEM:CLARIFYING SYSTEM:SOLIDS RECIRCULATION CLARIFIERSSOLIDS RECIRCULATION CLARIFIERS


• INDUSTRIAL CLARIFIERS EMPHASIZE ON SOLIDS CONTACT.

• A NUMBER OF DESIGNS ARE AVAILABLE. ACCORDING TO LATEST DEVELOPMENTS SOLIDS RECIRCULATION TYPE ARE MOSTLY PREFERRED DESIGN.

46



• SOILD RECICULATION CLARIFIERS COMBINE MIXING, FLOCCULATION AND SETTLING IN ONE TANK.

• INCOMING WATER IS MIXED WITH CHEMICALS & INTIMATE CONTACT WITH RECIRCULATING PRE FORMED SLUDGE IN A REACTION ZONE.

• FROM REACTION ZONE PASSES TO DETENTION ZONE WHERE GENTLE MIXING ENHANCES THE FORMATION OF FLOCS.

47



• THE RECIRCULATION RATE DEPENDS ON THE INCOMING WATER TURBIDITY. VARIABLE SPEED IS PROIVDED FOR RECIRCULATING DRIVE FOR THIS PURPOSE.

• CHEMICALS ARE ADDED INTO THE LOWER PORTION OF REACTION ZONE OF THE CLARIFIER. THESE CAN ALSO BE ADDED IN TO THE INCOMING RAW WATER FEED PIPE.

48

CLARIFYING SYSTEM:CLARIFYING SYSTEM:SOILDS RECIRCULATION CLARIFIERSSOILDS RECIRCULATION CLARIFIERS


• FLOC GETS FULLY DENSIFIED WHEN WATER LEAVES AT BOTTOM, SETTLING RAPIDALLY AS CLEAR WATER RISES.

• DUE TO THIS EFFECT USE OF HIGHER RISE RATES BECOMES POSSIBLE THAT REDUCES THE SIZE OF THE CLARIFIER.

53

TROUBLE SHOOTING CLARIFIER (S)

58


FILTRATIFILTRATIONON

59

FILTRATION:FILTRATION:RAW WATER TREATMENT RAW WATER TREATMENT

• FILTRATION COMPLETES THE WORK BEGUN BY CLARIFIERS

• FILTRATION IS BASICALLY A PROCESS OF PLACING A POROUS/PERVIOUS BARRIER ACROSS FLOWING WATER TO REMOVE MATTER HELD IN SUSPENSION.

• IN ITS SIMPLEST FORM CAN BE SURFACE OF THE BARRIER LIKE IN STRAINER OR BY REMOVAL THROUGHOUT THE DEPTH OF MEDIUM.

60


• SURFACE FILTRATION IS LIMITED IN ITS REMOVAL CAPACITY. FOR INDUSTRIAL USE MEDIUM DEPTH IS THE ONLY PRACTICAL SOLUTION.

• GRANULAR MEDIA ARE STANDARD FOR THIS PURPOSE.

• IT FEATURES A BED OF GRADED FINE MEDIA SUPPROTED BY GRAVEL OF DIFFERENT GRADINGS THAT PREVENTS THE PERCOLATION OF FINE FILTERING MEDIA INTO THE COLLECTION SYSTEM.

61


• OVERLYING WATER PERCOLATES THROUGH DOWN THROUGH THE MEDIA & IS COLLECTED AND REMOVED BY THE UNDERDRAIN SYTEM.

• VARIOUS MECHANISMS WORK DURING FILTRATION LIKE SIMPLE ADSORPTION, ELECTROSTATIC EFFECTS, CHEMICAL BRIDGING, OR A COMBINATION.

• THE PHYSICAL CHRACTERISTICS OF THE MEDIUM, FLOW RATE, PARTICLE SIZE, DENSITY, WATER TEMPERATURE AFFECT THE FILTER PERFORMANCE.

62

FILTER MEDIA

FLOCCULATION

SEDIMENTATION

FILTER PORE

STRAINING

WATER BEING FILTERED

INTERCEPTION

FLOC

0.5mm

BACTERIUM 0.001 mm

64

CROSS SECTION THROUGH SINGLE MEDIA UNSTRATIFIED BED

CROSS SECTION THROUGH SINGLE MEDIA STRATIFIED BED

CROSS SECTION THROUGH DUAL MEDIA STRATIFIED BED

CROSS SECTION THROUGH TRI MEDIA STRATIFIED BED

GRAIN SIZE GRAIN SIZE

GRAIN SIZE GRAIN SIZE

65

MEDIA PROPERTIES & SIZE:MEDIA PROPERTIES & SIZE:RAW WATER TREATMENT RAW WATER TREATMENT

• NATURAL SILICA SAND SP. GR.- 2.65.

• CRUSHED ANTHRACOAL SP. GR. 1.6 – 1.75

• ACTIVATED CARBON SP. GR. 0.4 – 0.7

• CRUSHED GARNET SP. GR. 4.1 TO 4.6

• MEDIA ARE SPECIFIED BY THE EFFECTAIVE SIZE AND UNIFORMITY COEFFICIENT.

• COMMERCIAL SCREENING IS UNIFORMITY COEFFICIENT 1.6 TO 1.7.

66

GRAIN SIZE

EFFECTIVE SIZE – d10 FOR WHICH 10% SAMPLE IS FINERUNIFORMITY COEFFICIENT – THE RATIO OF d60 FOR WHICH

60% SAMPLE IS FINER TO THE d10

67

BED DEPTH COMBINATIONS:BED DEPTH COMBINATIONS:RAW WATER TREATMENT RAW WATER TREATMENT

• 0.4-0.6 mm SAND 250-300 mm

• 1.0-1.2 mm SAND 600-900 mm

• 0.8-1.0 mm ANTHRACITE 300-600 mm

• 1.4-1.6 mm SAND/ANTHRACITE 750-900 mm



68

RAW WATER TREATMENTRAW WATER TREATMENTPRESSUPRESSURERE

FILTERSFILTERS

69

VERTCAL PRESSURE MEDIA FILTER

FEATURESFEATURES

•BOTTOM MEDIA SUPPORT AND COLLECTION /DISTRIBUTION SYSTEM.

•FRONTAL PIPEWORK WITH ARRANGED NEST OF VALVES.

•INSTRUMENTATION.

•INLET OUTLET CONNECTIONS.

•VERTICAL CYLINDERICAL VESSEL INSIDE SUITABLY PROTECTED.

RAW WATER TREATMENT RAW WATER TREATMENT

BED PLATE

STRAINER

73

RAW WATER TREATMENTRAW WATER TREATMENTGRAVITGRAVITYY

FILTERSFILTERS

75


SERVICE RUN GRAVITY FILTERS.

• DECLINING FLOW RATE.

• CONSTANT FLOW RATE.

GENERAL FILTER OPERATIONGENERAL FILTER OPERATION

76


BACKWASH.

• DRAIN.

• AIR SCOUR.

• SETTLE

• BACKWASH WITH FILTERED WATER

• RINSE

GENERAL FILTER OPERATIONGENERAL FILTER OPERATION

78

GENERAL FILTER OPERATION GENERAL FILTER OPERATION PROBLEMS:PROBLEMS:


EFFELUENT QUALITY.

• PARTICLE SIZE LESS THAN 10-20 MICRON NEED SOME MEANS OF FLOCCULATION.

• ACTIVATED SLUDGE PROCESS AND TRICKLING FILTERS HAVE 10-40% BY WEIGHT PARTICLE SIZE < 20 MICRON. IN THIS SIZE RANGE 60-90% REMOVAL IS OBTAINED.

79



SHORTER FILTER RUNS.

• INCREASE FILTRATION RATE

• CHANGE MEDIA GRAIN SIZE. FOR BIOLGICAL WASTE WATERS MEDIA GRAIN EFFECTIVE SIZE UP TO 2.5 mm CAN PROVIDE SATISFACTORY REMOVAL. RUN LENGTH CAN INCREASE 2 TO 3 TIMES THAN THAT WITH CONVENTIONAL 1.0 -2.0 mm. HOWEVER NEEDS CAREFUL STUDIES.

• INCREASE ALLOWABLE HEAD LOSS

80



INEFFECTIVE MEDIA CLEANING & MUDBALL FORMATION.

• INSUFFICIENT BACKWASH FLOWS.

• PROGRESSIVELY MEDIA MAY GET COATED DUE TO INSUFFICIENT CLEANING OR PRESENCE OF GREASE ETC. IN WASTE WATERS. THIS GROWTH ON MEDIA GRAINS LEADS TO MUDBALLING. CHLORINATION AND PROPER BACKWASH REGIME SHOULD BE FOLLOWED.

81



PLUGGED MEDIA SUPPORT SYSTEMS.• KEEP BACK WASH STORAGE WATER CLEAN.

• SELECT SUFFICIENT OPENING SIZE.

• ENSURE PROPER DISINFECTION OF INFLUENT AND BACKWASH WATER.

• AVOID SURGE OF WATER OR AIR INTO THE BACK WASH FLOWS.

82



MEDIA LOSS.• KEEP OPTIMUM BACK WASH FLOW RATE.

• KEEP MEDIA FREE FROM BIO FOULING SINCE ANY GROWTH AROUND GRAINS CAN REDUCE THEIR NET DENISTY.

• AVOID SURGE OF WATER OR AIR INTO THE BACK WASH FLOWS.

83

RAW WATER TREATMENTRAW WATER TREATMENTSLUDGSLUDGE E

HANDLIHANDLINGNG

84

SLUDGE HANDLING/TREATMENT:SLUDGE HANDLING/TREATMENT:RAW WATER TREATMENT RAW WATER TREATMENT

TYPICALLY COMPRISE.

• SLUDGE REMOVAL, COLLECTION & STORAGE.

• SLUDGE THICKENING.

• SLUDGE CONDITIONING.

• SLUDGE DEWATERING/DRYING RENDERING FOR TRANSPORTATION.

90

PLANT PLANT DATADATA

KURIMAT POWER STATIONKURIMAT POWER STATION

91

PLANT OVERVIEW:PLANT OVERVIEW:

Pretreatment plant

Education

Transcript of Pretreatment plant