water hardness
Post on 18-Nov-2014
983 Views
Preview:
DESCRIPTION
TRANSCRIPT
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
top related