WaterWater

Presented by:Presented by:

Sushil AhlawatSushil Ahlawat

Lecturer in chemistryLecturer in chemistry

GP AdampurGP Adampur

Nature‘s most wonderful, most abundant ,most Nature‘s most wonderful, most abundant ,most useful compound.useful compound.

Used for drinking ,bathing, sanitation ,washing Used for drinking ,bathing, sanitation ,washing and irrigation purposes.and irrigation purposes.

Used as coolant in power and chemical plants Used as coolant in power and chemical plants and also for steam generation. and also for steam generation.

In Industry it is used in production of steel, In Industry it is used in production of steel, paper industry, textile industry and food paper industry, textile industry and food processing industry.processing industry.

Sources and typesSources and types Rain waterRain water Soluble impurities: Soluble impurities: SOSO22, CO, CO22, HNO, HNO3,3,NO, NHNO, NH44NONO33

Insoluble impurities:Insoluble impurities: Soot & Dust Soot & Dust River waterRiver water Soluble impurities: Soluble impurities: SOSO2,2,COCO2,2,HNOHNO3,3, NO, NH NO, NH44NONO33

Insoluble impurities:Insoluble impurities: Clay ,Sand and PebbleClay ,Sand and Pebble

Spring waterSpring water

Soluble impurities: Soluble impurities: HH22S, NaS, Na22S, FeCOS, FeCO33, Fe(HCO, Fe(HCO33))22,,

MgSOMgSO44, MgCl, MgCl22

Insoluble Impurities: NoneInsoluble Impurities: None Sea waterSea water

Soluble impurities:-Soluble impurities:-NaCl, NaNaCl, Na22SOSO44, ,

KHCOKHCO3, 3, Ca(HCOCa(HCO33) ) 22 Mg(HCO Mg(HCO33))22,SO,SO22,CO,CO22

Insouble impurities:- Clay, Sand, pebblesInsouble impurities:- Clay, Sand, pebbles

Soft waterSoft water Form leather with soap.Form leather with soap.

Hard waterHard water Does not form leather easily.Does not form leather easily.

Causes of HardnessCauses of Hardness Hardness is due to presence of following salts.Hardness is due to presence of following salts.

Calcium BicarbonateCalcium Bicarbonate Magnesium Bicarbonate Magnesium Bicarbonate Calcium ChlorideCalcium Chloride Magnesium ChlorideMagnesium Chloride Calcium SulphateCalcium Sulphate Magnesium SulphateMagnesium Sulphate

Action of Soap on Hard Action of Soap on Hard WaterWater

2C2C1717HH3535COONa + Ca(HCOCOONa + Ca(HCO33) ) 22

(C(C1717HH3535COO) COO) 22 Ca + 2 NaHCO Ca + 2 NaHCO33

Action of Soap on Hard Action of Soap on Hard WaterWater

2C2C1717HH3535COONa + CaClCOONa + CaCl22

(C(C1717HH3535COO)COO)22Ca +2NaClCa +2NaCl

Types of HardnessTypes of Hardness

Temporary hardness:-Temporary hardness:- Due to bicarbonates of Calcium and Due to bicarbonates of Calcium and

Magnesium and removed by simple method like Magnesium and removed by simple method like boiling.boiling.

Permanent hardness:-Permanent hardness:- Due to chloride and sulphates of Calcium and Due to chloride and sulphates of Calcium and

Magnesium and require special methods for Magnesium and require special methods for removal.removal.

Disadvantages of Hard WaterDisadvantages of Hard Water

Hard water contain large amount of Hard water contain large amount of HCOHCO¯̄33,,

Cl Cl ¯̄SOSO¯̄44¯̄ salts of Ca & Mg and these have salts of Ca & Mg and these have undesirable effects . undesirable effects .

In domestic use In domestic use

In industrial useIn industrial use

In boiler In boiler

InIn domesticdomestic useuse Wastage of soapWastage of soap–– Hard water does not form Hard water does not form

good leather with soap.good leather with soap. Spoiling clothesSpoiling clothes – – Insoluble Ca & Mg salts stick Insoluble Ca & Mg salts stick

to the clothes in the form of scum .to the clothes in the form of scum . EncrustationEncrustation – –Ca and Mg salt deposits on the Ca and Mg salt deposits on the

inside of the container in which hard water is inside of the container in which hard water is boiled.boiled.

CookingCooking–– Pulses and vegetables do not cook Pulses and vegetables do not cook well in hard waterwell in hard water

In Industrial useIn Industrial use Paper industryPaper industry–– water is used along with soap water is used along with soap

for sizing the paper.for sizing the paper. Textile industryTextile industry – –water is used for cleaning , water is used for cleaning ,

washing and whitening of yarn.washing and whitening of yarn. DyeingDyeing – – Hard water spoils the desired shades. Hard water spoils the desired shades. Building constructionBuilding construction–– Chlorides and Sulphates Chlorides and Sulphates

of hard water affects hydration of cement and of hard water affects hydration of cement and hence quality.hence quality.

In Industrial useIn Industrial use Choking and clogging troublesChoking and clogging troubles–– water pipes water pipes

block due to precipitates of hard water salt and block due to precipitates of hard water salt and requires extra cost of maintenance and repair.requires extra cost of maintenance and repair.

Food industryFood industry–– Hard water affect quality of Hard water affect quality of processed food products.processed food products.

Sugar industrySugar industry–– Hard water salts affect Hard water salts affect crystallization process of sugar.crystallization process of sugar.

In BoilersIn BoilersIn industries ,water boilers are used for In industries ,water boilers are used for

steam generation and hard water causes steam generation and hard water causes following troubles:- following troubles:-

Formation of scale or sludgeFormation of scale or sludge–– Insoluble ppt. of Insoluble ppt. of Ca &MgCa &Mg salts stick to inner side of boiler salts stick to inner side of boiler as a permanent hard crust called scale & as a permanent hard crust called scale & if crust is soft it is called sludge . if crust is soft it is called sludge .

In BoilersIn Boilers DisadvantagesDisadvantages -- --

Scale is badScale is bad conductor of heat as a result wastage conductor of heat as a result wastage of fuel in steam generation .of fuel in steam generation .

More heat required for boiling and over heating More heat required for boiling and over heating shorten life of boiler.shorten life of boiler.

Due to over heating cracks in the scale appear and Due to over heating cracks in the scale appear and hot water come in contact with over heated boiler hot water come in contact with over heated boiler plates & suddenly changes into steam and this may plates & suddenly changes into steam and this may burst the boiler .burst the boiler .

In BoilersIn Boilers Corrosion Corrosion ----

MgClMgCl22 ,CO ,CO22 and and SOSO22 present in hard water present in hard water

form acids , which eat up the plates of boiler form acids , which eat up the plates of boiler called corrosioncalled corrosion

MgClMgCl22 +H +H22O O Mg(OH)Cl + HClMg(OH)Cl + HCl

COCO22+ H+ H22O O HH22COCO33

SOSO22 + H + H22O O HH22SOSO33

Fe + 2HCl Fe + 2HCl FeClFeCl22 + H + H22

In BoilersIn BoilersDisadvantagesDisadvantages

Corrosion shortens life of boiler.Corrosion shortens life of boiler. Joints attacked by acid and begin to leak.Joints attacked by acid and begin to leak. Cost of maintenance increases.Cost of maintenance increases.

Prevention Prevention Adding suitable amount of alkali Adding suitable amount of alkali NaOHNaOH, ,

NaNa22COCO33

Oxygen in water removed by adding Oxygen in water removed by adding reducing agents like reducing agents like FeSOFeSO44, Fe(OH, Fe(OH) ) 22

In BoilersIn Boilers Foaming and primingFoaming and priming

Due to suspended impurities ,large amount of Due to suspended impurities ,large amount of bubbles appear on the surface of water in the boiler bubbles appear on the surface of water in the boiler called foaming.called foaming.

When foaming become rapid and explosive the When foaming become rapid and explosive the enter the engine along with the steam and enter the engine along with the steam and decreases its efficiency called priming.decreases its efficiency called priming.

In BoilersIn Boilers DisadvantagesDisadvantages

Due to foaming and priming ,it is difficult to Due to foaming and priming ,it is difficult to maintain constant pressure of steam . Suspended maintain constant pressure of steam . Suspended impurities increases boiling point of water results impurities increases boiling point of water results wastage of fuel.wastage of fuel.

PreventionPrevention Foam forming substance i.e alkali and oily matter Foam forming substance i.e alkali and oily matter

should be removed .should be removed .

Degree of HardnessDegree of Hardness

It is measured to know strength of hardness It is measured to know strength of hardness causing substance in water and calculated in causing substance in water and calculated in term of CaCOterm of CaCO3.3.

Reason :-Reason :- CaCOCaCO33 being insoluble in water does not cause being insoluble in water does not cause

hardness in water hardness in water Mol. Wt. and Eq.Wt. of CaCOMol. Wt. and Eq.Wt. of CaCO33 is 100 and 50 is 100 and 50

respectively hence calculations become easy.respectively hence calculations become easy.

degree of hardnessdegree of hardness 1 gm molecule or 162 gm of Ca(HCO1 gm molecule or 162 gm of Ca(HCO33))2 2

= 1 gm molecule or 100 gm of CaCO= 1 gm molecule or 100 gm of CaCO33

1 gm molecule or 111 gm of CaCl1 gm molecule or 111 gm of CaCl22

= 1 gm molecule or 100 gm of CaCO= 1 gm molecule or 100 gm of CaCO33

1 gm molecule or 136 gm of CaSO1 gm molecule or 136 gm of CaSO4 4

= 1 gm molecule or 100 gm of CaCO= 1 gm molecule or 100 gm of CaCO33

1gm molecule or 120 gm of MgSO1gm molecule or 120 gm of MgSO44

= 1 gm molecule or 100 gm of= 1 gm molecule or 100 gm of CaCOCaCO33

UnitsUnits

Degree of hardness is expressed in three unitsDegree of hardness is expressed in three units Parts per million (ppm) Parts per million (ppm)

It is number of part by weight of hardness It is number of part by weight of hardness causing substance in term of causing substance in term of CaCOCaCO33 present present per million by weight of water.per million by weight of water.

French Degree (French Degree (ººFr)Fr)

It is number of part by weight of hardness It is number of part by weight of hardness causing substance in term of causing substance in term of CaCOCaCO33 present present per hundred thousand by weight of waterper hundred thousand by weight of water

UnitsUnitsClarks Degree (Clarks Degree (ººCl)Cl)

It is number of part by weight of hardness It is number of part by weight of hardness causing substance in term of causing substance in term of CaCOCaCO33 present present

per 70,000 by weight of water.per 70,000 by weight of water.

Relationship:Relationship:

7 degree on clark scale = 10 degree on french 7 degree on clark scale = 10 degree on french scale=100 on ppm scalescale=100 on ppm scale

Drinking water- Its criteriaDrinking water- Its criteria

A good Drinking water should be:A good Drinking water should be: Colorless and odorless.Colorless and odorless. Free from suspended impurities.Free from suspended impurities. Free from germs and bacteria.Free from germs and bacteria. Free from salts i.e.nitrites, nitrates and Free from salts i.e.nitrites, nitrates and

ammonia ect., Which are injurious to health.ammonia ect., Which are injurious to health.

Purification of waterPurification of water

Various steps involved are:Various steps involved are:

Removal of suspended impuritiesRemoval of suspended impurities Filtration Filtration

BoilingBoiling Coagulation & OxidationCoagulation & Oxidation AerationAeration

SterilizationSterilization ChlorinationChlorination OzonisationOzonisation UV lightUV light Copper sulphateCopper sulphate IodinationIodination

Removal of suspended impuritiesRemoval of suspended impurities

Standing in SunlightStanding in Sunlight

Water is allowed to stand undisturbed in a tank in Water is allowed to stand undisturbed in a tank in sunlight. Suspended impurities settles down and sunlight. Suspended impurities settles down and bacteria are killed by sunlight.bacteria are killed by sunlight.

Addition of chemicalsAddition of chemicals

Alum is added to coagulates these impurities. Alum is added to coagulates these impurities. Impurities settles down and carry most of bacteria Impurities settles down and carry most of bacteria with them . Upper clear layer is decanted off.with them . Upper clear layer is decanted off.

FiltrationFiltrationWater , Obtained after filtration is free from Water , Obtained after filtration is free from

suspended and bacterial impuritiessuspended and bacterial impuritiesTypesTypes

Domestic filtrationDomestic filtration

Laboratory filtrationLaboratory filtration

Pasteur filtrationPasteur filtration

SterilizationSterilization

Boiling Boiling

Pathogens are completely destroyed by boiling Pathogens are completely destroyed by boiling water for 10-15 minutes.water for 10-15 minutes.

Coagulation and oxidationCoagulation and oxidation

AlumAlum{K{K22SOSO44.Al.Al22 (SO (SO44) ) 33.24H.24H22OO }and }and KMnO KMnO 44

are used for this purposeare used for this purpose

SterilizationSterilization Aeration Aeration

Water is forced through perforated pipes. In this Water is forced through perforated pipes. In this way water comes in contact with oxygen and way water comes in contact with oxygen and UV rays of sun. UV rays of sun.

UV rays kill bacteria and Oxygen of air oxidises UV rays kill bacteria and Oxygen of air oxidises the organic matter.the organic matter.

SterilizationSterilization ChlorinationChlorination

Chlorine is very effective for sterilizing water. It Chlorine is very effective for sterilizing water. It is added either as liquid or as bleaching is added either as liquid or as bleaching powder. Excess of chlorine should be avoided.powder. Excess of chlorine should be avoided.

OzonisationOzonisation

Either ozone is bubbled through water or current Either ozone is bubbled through water or current of ozone is passed up a tower from the top of of ozone is passed up a tower from the top of which water is introduced.which water is introduced.

SterilizationSterilization UV lightUV lightUV rays are very effective sterlizer.water is UV rays are very effective sterlizer.water is

exposed for a very short time to the UV rays exposed for a very short time to the UV rays produced from mercury vapour lamps produced from mercury vapour lamps enclosed in a quarts container.enclosed in a quarts container.

Copper Sulphate & IodinationCopper Sulphate & Iodination

Small quantity of CuSOSmall quantity of CuSO44 & Iodine is Added to & Iodine is Added to destroy microorganisms ,which impart destroy microorganisms ,which impart undesirable colour and odour to waterundesirable colour and odour to water

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