1

HARDNESS OF WATER & ITS TREATMENT

Dr.Shahid Mahmood Assistant Professor

Department of Community Medicine

Fatima Jinnah Medical College Lahore

Lectu

re -

6

ACKNOWLEDGEMENTS

Park K. Textbook of Preventive and Social Medicine

Iliyas - Shah Public health and Community Medicine

Maxcy- Rosenau-Last. Public health and Preventive Medicine

o World Health Organization (WHO)

owww.google.com/ images

2

SESSION PLAN

Recap

1. Factors associated with water hardness2. Methods how to treat hard water.3. Hazards related to hardness of water

3

4

RECAP Q. Action of Chlorine for disinfection of water

is maximum when water pH is around :

A. 3.0 B. 5.0 C. 7.0 D. 9.0

Answer : C

Double pot method of well disinfection

5

Q.2 Action of Chlorine for disinfection

depends upon :

A. pH B. Temperature C. Contact time D. All of the above

Answer : D

Chlorine added

Fre

e R

esi

du

al

C

l

Break point

Chloramines

6

MODIFIED BRADLEY- FEACHEM CLASSIFICATION

S# Types of diseases Features

1 Faeco -oral diseases Routes of transmission. Diarrhoel diseases , dysentry , hepatitis A

2 Water borne diseases Contamination of water by animal and human faeces, urine . Cholera, typhoid ,leptospirosis

3 Water washed diseases

Scarcity and inaccessibility of water. Non-washing of hand, skin. Typhus, scabies,

4 Water based diseases Water provides habitat for intermediate host. Schistosomiasis, liver flukes, dracunculiasis

5 Water related vector diseases

Malaria, Filariasis, dengue , yellow fever , river blindness [ mosquito and fly breeding sites in water]

6 Water dispersed diseases

Legionella infection. Bacetria resides in air conditioning water system , fresh water amoeba

7

WATER RELATED NON- INFECTIOUS DISEASES

S# Agents Diseases

1 Iodine Deficient in water Goiter , Hypothyroidism

2 Excess fluoride Dental Fluorosis

3 Fluoride Deficiency Dental Caries

4 Excess Inorganic salts Diarrhea

5 Cadmium Gastric upsets , Nephropathy

6 Sodium Hypertension

7 Sulfates Laxative effect

8 Nitrates and Nitrites Methaemoglobinemia

9 lead Lead poisoning

10 Arsenic Skin and lung diseases

11 Mercury Nephropathy

8

BOTTLED WATER Drinking water that is sold for human consumption in sanitary container.

Plain bottled drinking water should not contain any sweetener, chemical additives.

It should be calorie free and sugar free.

Bottled water containing less than 250 PPM total dissolved solids is called ‘ Mineral Water’

9

HARDNESS OF WATER

Soap –destroying power of water

Large quantities of soap or detergent required to produce foam /lather

10

ORIGIN OF HARDNESS - MECHANISM

From Rocks & land , sediments

11

WHAT CAUSED THE HARDNESS OF WATER?

Mainly due to Four Dissolved Compounds :

1. Calcium Bicarbonate 2. Magnesium Bicarbonate 3. Calcium Sulphate4. Magnesium SulphateLess Common: 5. Calcium Chlorides and Nitrates 6. Magnesium Chloride and Nitrates7. Iron and Manganese salts8. Aluminium Compounds

12

HOW HARDNESS CLASSIFIED?

Hardness of water Carbonate Hardness

(Temporary Hardness)Calcium & Magnesium

Bicarbonates

Non-Carbonate hardness

(Permanent Hardness)

Calcium SulphateMagnesium

SulphateCalcium Nitrates

Magnesium Nitrates

Calcium and Magnesium Chlorides

13

MEASUREMENT OF HARDNESS Expressed as milli -equivalent per litre (m Eq/l) or

mg/L 1 mEq /l of hardness = 50mg CaCO3 (50ppm) in

one litre mEq/L 1 3 6

14

BAD THINGS ABOUT HARDNESS ( DISADVANTAGES)

Consumes More soap and detergent - Financial loss.

When water boiled , Carbonates

precipitates , deposited in boiler , require

more energy for heating: Industrial loss

and boiler inefficiency , may explode

Shorten the life of cloth fabrics

Not suited for various industrial

processes

Shorten life span of pipes (deposition

and scaling of salts)

15

REMOVAL OF HARDNESS

1. Boiling 2. Addition of lime 3. Addition of sodium carbonates 4. Base exchange process

5. Addition of Sodium carbonate 6. Base exchange process

Temporary Hardness

Permanent Hardness

16

METHODS TO REMOVE HARDNESS

Boiling : (Expensive , no large scale use)

Ca (HCO3)2 Ca CO3 + H2O + CO2

Insoluble PrecipitateCalcium carbonate

o Addition of Lime

Ca(OH)2 + Ca (HCO3)2 CaCO3 + H2O

Lime

17

ADDITION OF SODIUM CARBONATE (SODA ASH)

Removes both temporary and permanent hardness

Na2 CO3 + Ca (HCO3)2 NaHCO3 + CaCO3CaSO4 + Na2CO3 CaCO3 + Na2SO4

Base Exchange Process (large scale)

1. Sodium Permutit is used ( Na2Al2 Si2O H2O )2. Exchange Na ions for Ca and Mg ions3. Ca and Mg Permutit is formed .4. Removes 100% hardness 5. Some raw water is added to protect against

corrosive action of 100% soft water

18

Fluoridation & Defluoridation of water

Is Naturally present in land Essential for dental and bone health Deficiency = dental caries Excess = Dental fluorosis ; Skeletal fluorosis 1 ppm is the optimum requirement in water Fluoridation = ++ Fluoride level fluoride level. Defluoridation is the process of removing excess fL. Using Phosphate.

19

ASSIGNMENT WORD LIMIT : 250 WORDS SUBMIT AT 9.30 AM (28TH JAN -12) REWARD : ATTENDANCE HAND WRITTEN

Write Short Answers of following questions:

1. Differentiate between Break point Chlorination and Super-chlorination

2. Name health hazards associated with using swimming pool. 3. Name Bacterial diseases related with drinking polluted

water 4. Differentiate between shallow well and deep well

5. Name Hazards associated with surface water.

20

Thank you