Water Treatment Basic process discription

What is the feed water parameter need to maintain the RO feed and how to remove the havey metal from effulent. what are the other parameter need to considered the pre treatment design parts and Post treatment parts.

1. 1
st
day training on
Basic water chemistry
Basic Pre treatments
Dosage calculation

2. SOURCES OF WATER FOR INDUSTRIAL
USE
Surface waters -Rivers, canals and lakes
Surface waters -Sea Water
Ground waters -Borewells
Municipal supply
Water recovered from treatment of industrial
effluents / municipal sewage.

3. IMPURITIES IN SURFACE WATERS
Undissolved Impurities
Suspended solids
Colloidal particles
Organic matter
Algae
Bacteria including faecal
contamination

4. Dissolved Impurities
Mineral salts present as Ions
Organic matter (humic&fulvic acids)
Detergents, lignosulfonic acids &
organo-phosphates
Pesticides & Herbicides(from agri run
off)
Dissolved gases.
… IMPURITIES IN SURFACE WATERS

5. Undissolved impurities
Groundwatersaregenerallyfreefrom
undissolvedimpurities.Insome areas,
however,waterisclearwhendrawnbutsoon
turnsturbidonexposuretoairduetopresence
ofironand/ormanganese.
IMPURITIES IN GROUND WATERS

6. Dissolved impurities
Mineral salts present as ions
Iron, Manganese
Fluoride
Arsenic
Nitrate
Dissolved gases.
… IMPURITIES IN GROUND WATERS

7. GENERAL CHARACTERISTICS
River, canal and lake waters
Seasonal variations in suspended solids,silt,
colloidal silica,organic matter(humic and
fulvic acids) which are high during monsoon
Low dissolved solids
Low in algae
Pollution from industrial/domestic wastes.

8. … GENERAL CHARACTERISTICS
Sea Water
Same as rivers, canals and lakes, except that it is
very high in total dissolved solids.

9. Ground waters
Relatively free from suspended solids and
colloidal particles
Low in organic matter
High in dissolved solids
Relatively free from industrial / domestic
pollution.
… GENERAL CHARACTERISTICS

10. Ground waters
Waters from some areas like West Bengal may
contain high levels of iron and / or manganese.
These waters are relatively clear when drawn but
turn turbid due to oxidation of iron and / or
manganese
Fluoride is present in some areas like Rajasthan,
Deccan Plateau and Madhya Pradesh
Arsenic is present in West Bengal and
Bangladesh.
… GENERAL CHARACTERISTICS

11. Water supplied through municipal corporation
Thesewatersaregenerallydrawnfrom
surfacewatersourcesandareclarified,
filteredandchlorinatedandareofpotable
waterquality.
… GENERAL CHARACTERISTICS

12. COMPARISON OF SURFACE WATER,
GROUNDWATER AND SEAWATER
Parameter Surface WaterGroundwater Sea Water
Temperature Variable Constant Variable
Suspended solidsLow – High Absent Low - High
Turbidity Low – High Very low Low
Organic matter Low – High Very low Low – High
Dissolved oxygenNear saturationNearly absent Near saturation
Salinity Low – Medium Medium – High Very High

13. WATER ANALYSIS
REPORT
Client
SamplingDate
Source
Parameter
Colour
Odour
Taste
SuspendedSolids mg/l
Turbidity NTU
pH
PAlkalinity mg/lCaCO
3
MAlkalinity mg/lCaCO
3
Equivalent MineralAcidity mg/1 CaCO
3

14. … WATER ANALYSIS
REPORT
Chloride mg/l
Sulphate mg/l
Total Hardness mg/l CaCO
3
Calcium mg/l
Magnesium mg/l
Sodium mg/l
Iron mg/l
Silica mg/l
Total Dissolved Solids mg/l
Conductivity mS/cm
Oxygen Absorbed mg/l
Chemical Oxygen Demand mg/l
Biochemical Oxygen Demand mg/l
Total Organic Carbon mg/l

15. COLOUR
•Indicatesgenerallythepresenceofundesirable
dissolved,colloidalandsuspendedimpuritiesin
thewater
Examples:
•Ironturnswatertobrown/red
•Manganesemakesitblack
•Organicsmaycolourityellow
•Objectionablefromanaestheticstandpoint.

16. ODOUR &
TASTE
•Indicatorsofundesirableimpurities
suchashydrogensulphideorsewage
contamination
•Importantparameterforwaterquality
controlinthefoodandbeverage
industry.

17. TURBIDIT
Y
•Indicateslevelofcolloidalmatterof
inorganicororganicorigin
•Suspendedsolidsandcolloidalmatter
makewaterturbid
•Noquantifiablerelationshipbetween
turbidityandsuspendedsolids.

18. •pH=-Iog[H
+
]
[H
+
]=concentrationofhydrogenionmole/l
•pHofpurewateris7
•pHscalerangesfrom0-14with7asneutral
point
•pHbelow7representsanacidicmedium
•pHabove7indicatesanalkalinemedium.
pH

19. ALKALINIT
Y
•Indicatesthequantitiesofbicarbonate,
carbonateandhydroxideinwateroralkaline
saltcontentofwater
•Determined using two indicators-
PhenolphthaleinandMethylOrange
•PhenolphthaleingivesthePAlkalinity,PAlkor
Pvalue
•MethylOrangegivestheMAlkalinity,MAlkor
Mvalue
•Bicarbonate,carbonateandhydroxideare
determinedfromthePvalueandMvalueby
thealkalinityrelationship.

20. ALKALINITY RELATIONSHIP

21. EQUIVALENT MINERAL ACIDITY (EMA)
•Indicatesneutralsaltcontentofwater
andcomprisesthechloride,sulphate
andnitratepresentinwater
•Nottobeconfusedwithfreemineral
acidity(FMA)whichrepresentsthe
actualaciditypresentinwater.

22. TOTAL HARDNESS (TH)
•Indicatesessentiallythecontentofcalcium
andmagnesiuminwater
•Apartoftotalhardnessisassociatedwith
alkalinityinwaterandisreferredasalkaline
hardness,carbonatehardnessortemporary
hardness
•ThebalanceisassociatedwiththeEMAof
waterandiscallednon-alkalinehardness,
non-carbonatehardness orpermanent
hardness.

23. SILICA
•DissolvedinwaterinmolecularformSiO2or
hydrolysedastheacidH2SiO3(silicicacid)
•Alsopresentinwaterinundissolvedstateor
colloidalformaspolymericsilica(SiO2)nora
complexcolloidthatincludesorganicmaterial
andheavymetalions
•Colloidalsilicainwaterisconvertedtothe
dissolvedstateundertheactionofhigh
temperatureandpressureasexperiencedina
boilerorautoclave
•Colloidalsilicaisremovedsubstantiallyby
coagulation,flocculation,sedimentationand
filtration.Itistotallyexcludedinultrafilters.

24. TOTAL DISSOLVED SOLIDS
(TDS)
•Indicatestotalcontentofdissolvedsolidsin
water
•Representsallchargedions-cationsand
anions-aswellasunchargedandmolecular
species
•Summationof
cationsmainlycalcium,magnesium,sodium;
anionsmainlybicarbonate,chloride,sulphate
andsilica.

25. ELECTRICAL
CONDUCTIVITY
•Atrueindicationofthepurityofwater
•Highertheconductivity,higherthe
contentofions,highertheimpuritiesin
waterandviceversa
•Anempiricalrelationshipexistsbetween
electricalconductivityandTDS
•Electricalconductivityistemperature
sensitive.

26. ORGANIC MATTER
•Coversallsubstances inwater
susceptibletooxidationandexpressed
byvariousindicesstatedbelow
•PermanganateValue(OxygenAbsorbed,
OAvalue)includesmatteroxidisedby
acidifiedpotassiumpermanganatefor4
hoursat27ºC.Indicatesorganicmatter
ofnaturalvegetableoriginsuchashumic
andfulvicacids.

27. … ORGANIC MATTER
•ChemicalOxygenDemand(COD)
Indicatesorganicmatteroxidisedbyhot
acidifiedpotassiumdichromate
Coversthemajorityoforganic
compoundsandoxidizablemineralsalts
Atermcommonlyusedinwastewater
treatmentplants

28. … ORGANIC MATTER
•BiochemicalOxygenDemand(BOD)
Representstheamountofoxygenused
bymicroorganismstoconsume
biodegradableorganicsinwastewater
underaerobicconditions
Generallysampleisincubatedfor5days
andtheresultreportedasBOD5

29. … ORGANIC MATTER
•TotalOrganicCarbon
Indicatesthecontentofcarbonlinkedto
organicmaterialbymeasuringthecarbon
dioxideaftercompleteoxidation
Aquickmethodtotestthetotalorganic
mattercontentofwatersample
Difficulttocorrelatewiththeother
measurementsindicatedearlier.

30. UNITS OF CONCENTRATION
•Volumetricconcentration
Thisisameasureofthequantityofmatter
dissolvedordispersedinagivenvolumeof
water
Itisindicatedasmg/l,g/l,g/m
3
,kg/m
3
Alsoexpressedinpercentageform%w/v
x%w/vmeansxkgofpuresubstanceare
presentin100lofsolution.

31. … UNITS OF
CONCENTRATION
•Milliequivalentperliter(meq/l)
•Equivalentperlitre(eq/l)

32. … UNITS OF
CONCENTRATION
•Weightconcentration
Thisisthequantitydissolvedordispersedina
givenweightofwater
Itisindicatedasmg/kg,g/torppm(partsper
million)
Asdensityofwateris1kg/l,theppmis
synonymouswithmg/l
Alsoexpressedinpercentageformas%w/w
x%w/wmeansxkgpuresubstancearepresent
in100kgofsolution.

33. … UNITS OF
CONCENTRATION
•mg CaCO
3/l or ppm CaCO
3

34. 1Englishdegree=1grain/gal
=14.38ppmCaCO
3
1Germandegree=10mgCaO/l
=17.86ppmCaCO
3
1Frenchdegree=N/5000
=10ppmCaCO
3
… UNITS OF
CONCENTRATION

35. USEFUL RELATIONSHIPS

EMA = Chloride + Sulphate + Nitrate
TC = EMA + M Alk.
TA = TC + Free Carbon Dioxide + Silica
Sodium = TC – TH
Temporary Hardness = M Alk if TH > M Alk
= TH if TH < M Alk
Permanent Hardness = TH – M Alk

Sodium Alkalinity = M Alk – TH

Where
TC refers to Total Cations
TA refers to Total Anions
TH refers to Total Hardness
M Alk refers to Total Alkalinity
EMA refers to Equivalent Mineral Acidity

36. •TC = EMA + M Alk = 400 ppm CaCO
3
Na = TC -TH = 100 ppm CaCO
3
•Temporary Hardness = M Alk as TH > M Alk
Temporary Hardness = 250 ppm CaCO
3
•Permanent Hardness = TH -M Alk = 50 ppm CaCO
3
SOLVED PROBLEM
EMA = 150 M Alk = 250 TH = 300
All figures are expressed as ppm CaCO
3
Find Sodium, Temporary Hardness, Permanent
Hardness

37. MAlk ppmCaCO
3 200
TH ppmCaCO
3 150
EMA ppmCaCO
3 150
FindSodium,TemporaryHardness,Permanent
HardnessandSodiumAlkalinity.
PROBLEM TO BE SOLVED

38. MAlk ppmCaCO
3 300
EMA ppmCaCO
3 200
Calcium mg/l 80
Magnesium mg/l 24
FindSodium,TemporaryHardness,Permanent
HardnessandSodiumAlkalinity.
PROBLEM TO BE SOLVED

39. UNIT PROCESSES FOR REMOVAL OF
UNDISSOLVED IMPURITIES
Settling
Chlorination
Coagulation
Flocculation
Clarification and
Settling
Filtration

40. Flocculation
Clarification
and Settling
Filtration
Settling Coagulation
… UNIT PROCESSES FOR REMOVAL
OF UNDISSOLVED IMPURITIES
Chlorination

41. SETTLING
Bulk of the suspended solids present in water will
settle down.
Settling velocity is governed by Stokes Law.
It is proportional to particle density & square of
particle diameter.
Settling tank will require periodical cleaning
which can pose problems.

42. Basics of Pretreatment and
Dosage Calculation

43. CHLORINATION
To oxidise dissolved organic
matter
To destroy algae and
pathogenic bacteria.

44. … Chlorination
Chlorination can be carried out by:
Chlorine gas/liquid
Sodium hypochlorite solution
Bleach liquor
MIOX-electro chlorination

45. … Chlorination
Chlorine in water dissociates to form
hypochlorous (HOCl) and hydrochloric (HCl)
acids.
HOCl dissociates to give hypochlorite (OCl)and
hydrogen (H) ions.
pH < 5 free chlorine exists
pH 5 -8 HOCl predominates
pH > 8 OCl predominates.
pH 5 -8 is desirable as HOCl is 80% and
more effective than OCl ion

46. …Chlorination
To be effective both dosage and contact
time are important.
A free residual chlorine (FRC) of 0.1 -0.2
mg/l ensures absence of pathogenic
bacteria.

47. Coagulation
Surfaces of colloidal particles carry
negative charges. They do not collide with
each other as like charges repel.
Involves addition of a coagulant like Alum in
a flash mixer of 30-60 sec detention time.
Alum[Al
2(SO
4)
3.18 H
2O] dissolves in water
and dissociates to give Al and SO
4ions.

48. •Alcationsneutralisethenegativechargeson
colloidalparticles.
•InadditionafluffyprecipitateofAl(OH)
3is
formedwhichadsorbsthefineparticles
resultinginalargerandeasilysettling
particle.
…Coagulation

49. …Coagulation
Jar tests are necessary to:
Select the right combination of a
coagulant, flocculant and their dosages.
Establish the optimum pH required.
Observe the floc size and consistency.
Soft flocs are reversible and hard ones
are not.

50. … Coagulation
Thepracticalcoagulantsusedare
AluminiumSulphate(Alum) Al
2
(SO
4
)
3
•18H
2
O
FerricChloride FeCl
3
•6H
2
O
FerricSulphate Fe
2
(SO
4
)
3
•9H
2
O
FerrousSulphate FeSO
4
•7H
2
O
SodiumAluminate Na
2
Al
2
O
4
PolyaluminiumChloride PAC
Polyferricsulphate PFS

51. … Coagulation Effect on Water Composition
(With addition of each ppm of pure chemical)
ppm Ca CO 3 change
Chemical Molecular
weight
M AlkCO2 SO4 Cl Ca Na
Alum 666 - 0.45+ 0.45+ 0.45 - - -
Sodium Aluminate 164 + 0.61- 0.61 - - - + 0.61
Ferric Chloride 270 - 0.55+ 0.55 - + 0.55 - -
Ferric Sulphate 562 - 0.53+ 0.53+ 0.53 - - -
Ferrous Sulphate 278 - 0.36+ 0.36+ 0.36 - - -
Lime 74 + 1.35- 1.35 - - + 1.35 -

52. Flocculation
Flocculation involves the addition of a
coagulant aid-a high molecular weight
(>100,000) polyelectrolyte in flocculator of 30
minutes detention time
Its function is to agglomerate the flocs
formed by the addition of the coagulant
Gentle agitation ensures agglomeration of
floc.

53. CLARIFICATION AND SETTLING
Intimate mixing between coagulants and raw
water.
Contact time with gentle agitation for floc
formation and its agglomeration
Sedimentation zone for separation of floc from
upflow of water.
Efficient removal of sludge
Collection of treated water through launders.

54. Clarification and settling of flocs is done in a
clarifier. Clarifier types are:
Circular scraped clarifiers
Sludge blanket clarifier / Precipitator
Lamella clarifier
High rate solids contact clarifier
Ultra high rate solids contact clarifier
… CLARIFICATION AND SETTLING

55. … CLARIFICATION & SETTLING
Clariflocculator
DESLUDGING
VALVE

56. … CLARIFICATION & SETTLING
Solids Contact Clarifier
CLARIFIED
WATER

57. … CLARIFICATION AND SETTLING
Lamella Clarifier

58. … CLARIFICATION & SETTLING
High Rate Solids Contact Clarifier

59. Dosage Calculation.

60. Assume:
Solution Concentration require:C% w/v
Volume of the Tank/Solution:V m3.
Purity of the chemical P%
So the quantity of chemical will be in Kg.
=1000CV/P
Calculation for the Chemical quantities for
preparations of Solution:

61. Dosage fixed –d ppm
Flow rate of system-F m3/hr
Concentration of the chemical to be dosed is
-C%.
So the flow rate of the pump will be-
FXd/10XC lit/hr.
If the rated capacity is f lit/hr.
The stroke setting % of pump_-(i/f )X100
Calculation of flow rates/selection of pump
stroke and setting of pump stroke.

62. Assessment for first day:
1.Write down 10 testing parameters of water.
2.Write the name of the salts which causes Permanent Hardness.
3.Write down one units of turbidity.
4.What is alkalinity?
5.How many kinds of Alkalinity is there?write there names.
6.Why we use alum in water?
7.Suppose you have to dose one chemical in water, it’s market
purity is 60% . It is solid. You have to dose it by 15 ppm in 15
M3/hr for 20 hrs.. What will be the amount of water and Chemical
amount?What will be the flow rate/hr?
8.Suppose you have to dose Sodium Hypo Chlorite in water. Market
availability is 6%. You have to dose 1 % solution and 2 ppm for 20
hrs and in 10 M3/hr. What will be the amount of water and
Chemical amount?What will be the flow rate/hr?
9.What is EMA?How do we Calculate it?
10.How can you measure Total Anions ?

63. Thank you