The document discusses environmental health and sanitation. It defines environment and discusses various physical, biological, and social environmental factors. Poor sanitation and pollution of air, water, and soil are linked to ill health. Maintaining a healthy environment requires a multi-disciplinary approach. The document focuses on water specifically, outlining different water sources, related health issues, and purification methods. It emphasizes the importance of access to safe drinking water and discusses large-scale water treatment involving storage, filtration, and chlorine disinfection.

1. ENVIRONMENT AND
HEALTH
Dr.Suresh Babu
Professor
Dept of Public Health Dentistry
Navodaya Dental College

2. Environment is defined as, all the physical,
chemical and Biological factors external to
a person and all the related behaviors”
-WHO Report 2006

3. (i) Physical - Water, air, soil, housing, wastes,
radiation, etc.
(ii) Biologic - Plant and animal life including
bacteria, viruses, insects, rodents
and animals.
(iii) Social - Customs, culture, habits, income,
Occupation, religion, etc.

4.  Much of man's ill-health can be traced to
adverse environmental factors
 Pollution of environment

5. Sanitation
 Being a way of life it must come from with in
the people, it is nourished by knowledge and
grow as an obligation and an ideal in human
relation.

6. WHO defines the environmental sanitation
as, “The control of all those factors in
man’s physical environment, which
exercise or may exercise a deleterious
effect on his Physical development, health
and survival”.

7.  The term sanitation covers the whole field of
controlling the environment with a view to
prevent disease and promote health
 Man has already controlled many factors
 The attainment of healthy environment is
becoming more and more complex

8. The term environmental sanitation is now
being replaced by environmental health.
 Proper environmental health now requires the
services of the public health qualified doctor,
the epidemiologist, the public health
engineer, the town planner, the sociologist,
the economist, and the health inspector

9.  The purpose of environmental health is to
create and maintain ecological conditions that
will promote health and thus prevent disease
 Two of the changes needed to achieve
Health for All are concerned with a healthy
environment and healthy lifestyle and require
initiatives by the individual, the family and the
community

10.  In India, much of ill health is due to poor
environmental sanitation
 Improvement of environmental sanitation is
crucial for prevention of disease and
promotion of health

11. WATER

12.  There can be no state of positive health and
well-being without safe water
 Water is not only a vital environmental factor
to all forms of life, but it has also a great role
to play in socio-economic development of
human population.

13.  In 1980, the United Nations General
Assembly launched
the International Drinking Water Supply
and Sanitation Decade,
1981-1990
--- the aim being to provide all people with
adequate supplies of safe water and
sanitation by 1990.

14.  In 1981, the 34th World Health Assembly
in a resolution emphasized that
safe drinking water is a basic element of
"primary health care"
which is the key to the attainment of
"Health for All by the year 2000 AD".

15. Safe & wholesome water
 Free from pathogenic agent
 Free from harmful chemical substances
 Pleasant to the taste
 Usable for domestic purposes

16. Water pollution is a growing hazard in
many developing countries due to human
activity.
Without ample and safe drinking water,
we cannot provide health care to the
community.

17. Water requirement
Basic physiological requirement
- 2 litres / head / day
 Urban domestic purpose - 150-200 litres.
 Rural India - 40 litres

18. uses of WATER
 Domestic use
 Public purpose
 Industrial purpose
 Agricultural purpose
 Power production
 Carrying away waste

19. sources of WATER supply
1)Rain water
2)Surface water-
Impounding reservoirs, rivers & streams,
tanks, ponds & lakes
3)Ground water-
shallow wells, deep wells, springs.

20. i. Rain
 Prime source of all water
 3 ways of distribution- water cycle
Characteristics of rain water
 Physically
 Chemically
 bacteriologically

21. Impurities of rain water
ACID RAIN.

22. ii. Surface water
 Originates from rain water
 Prone to contamination
 Unsafe for consumption- highest organic,
bacterial, viral contamination

23. a. Impounding reservoirs
Artificial lakes
Chennai. mumbai. Nagpur
Storing water for long duration

24. Characteristics:
 Fairly good quality of water next to rain water.
 Soft and free from pathogenic organism
Impurities:
 Impurity is from “catchment area”-human habilitation and
animal keeping.

25. b. Rivers
 Many rivers furnish a dependable supply of
water.
 Delhi, Kolkata, Allahabad
 Grossly polluted

26.  CHARACTERISTICS:
River water is turbid during rainy season
Contains dissolved and suspended
impurities of all kinds
The bacterial count may be very high

27.  IMPURITIES : Rivers are described as a
direct connection between the alimentary
canal of the people living upstream and the
mouths of those below.
 Self purification

28. c. Tanks
 Large excavations
 Indian villages
 highly susceptible to contamination
 Tank water is drunk

29. Improvement of tanks
 Elevated edges
 Fenced
 No one should get into tank
 Elevated platform to draw water.
 Weeds s/b removed
 Cleaned at the end of dry season.
 Sand filtration.
 Addition of Chlorine

30. d. Sea water
 Plentiful but not potable
 3.5% of salts in solution
 30-36 g/litre of salt concentration
 19 gm chloride,10.6 gm of sodium,1.2 gm of
magnesium / litre of water

31. iii. Ground water
 Cheapest and most practical
 Ground water is superior to surface water

32. Advantages
Disadvantages
The usual ground water sources are wells and
springs.

33. a. Wells
Traditionally wells are an important source of
water supply.
Types: (Technically)
Shallow:
Most of the wells in India are of the shallow
type
Shallow wells are liable to pollution from
neighboring sources of contamination

34. Deep:
Deep wells are usually machine-dug and
may be several hundred meters deep
Furnish safest water
Artesian well water rises above ground level.
Saline intrusion

36. Classified according to the method of
construction
1. Dug well – i. unlined katcha well
ii. Masonry / pucca well.
2. Tube well

37. SANITARY WELL
A sanitary well is one which is properly located,
well constructed and protected against
contamination with a view to yield a supply of
safe water
 LOCATION – 50 feet
 LINING- 20 feet
 PARAPET WALL – 28 inches
 PLATFORM – 3 feet
 COVERING
 HAND-PUMP
 CONSUMER RESPONSIBILITY

38. b. Springs
 When ground water comes to the surface and
flows freely under natural pressure, it is
called a "spring"
 shallow springs
 deep springs

39. WATER POLLUTION
 Pure uncontaminated water does not occur in
nature.
Natural
 Dissolved gases, minerals, suspended
impurities and microorganisms.

40. human activity
 Sewage –decomposable organic matter
and pathogenic agents
 Industrial and trade waste- metal salts,
chemicals
 Agricultural pollutants- fertilizers, pesticides.
 Physical pollutants: heat and radioactive
pollutants.

41. Water related disease

42. A. Biological (water borne disease)
i. Those caused by the presence of an infective agent
 Viral - hepatitis A and E, polio, rotavirus,
diarrhoea in infants
 Bacterial - Typhoid and Paratyphoid fever,
Bacillary dysentery, E.Coli diarrhoea & cholera,
 Protozoal - amoebiasis, giardiasis.
 Helminthic - round worm, threadworm, hydatid
disease
 Leptospiral- weil’s disease

43. ii. Those due to the presence of an aquatic host
 Snail- Schistosomiasis
 Cyclops- guineaworm, fish tape worm.

44. B.Chemical
 Detergent solvents, cyanides, heavy metals,
minerals, organic acids, nitrogenous
substances, bleaching agents,
dyes,pigments,sulphides & ammonia.

45.  Dental health
 Cyanosis in infant: high nitrate content
 Cardiovascular diseases: hardness is
beneficial
 Inadequate use of water : Conjunctivitis,
scabies, ascariasis, shigellosis, trachoma
 Insects breeding in water : Malaria, filaria,
arboviruses, African trypanosomiasis.

46. Pollution seems to be an inevitable consequence
of modern industrial technology,
the problem now is
To determine the level of pollution that permits
economic and social development without
presenting hazards to health,

47.  The evaluation of the health effects of
environmental pollutants is currently being
carried out as part of the WHO Environmental
Health Criteria Programme

48. Water pollution law
 Parliament in 1974 passed water [prevention
and control of pollution] act
 It provides for the constitution of Central and
State Water boards and Joint Water Boards
capable with wide powers for controlling
pollution.

49. Purification
 On a large scale
 On a small scale

50. PURIFICATION OF WATER
(A)LARGE SCALE
Storage
Filtration
Slow sand filters
Rapid sand filters
Disinfection
(B) SMALL SCALE
 House hold purification
Boiling
Filtration
Chemical disinfection
 Disinfection of wells
 DOUBLE-POT method

51. Purification of water on a
large scale
 The components of a typical water purification
system comprise one or more of the following
measures
Storage
Filtration
Disinfection

52. STORAGE
 Storage provides a reserve of water from
which further pollution is excluded
 This is natural purification, and we may look
at it from three points of view
Physical
Chemical
Biological

53. FILTRATION
 98-99 per cent of the bacteria are removed
by filtration apart from other impurities.
 Two types of filters :
Biological
Mechanical

54. BIOLOGICAL OR SLOW SAND
FILTERS
 1804 in Scotland
 Accepted as the standard method of water
purification

55. Elements of a slow sand filter
 supernatant (raw) water
 A bed of graded sand
 Under-drainage system
 System of filter control valves.

57. supernatant (raw) water
 Constant head of water
 Waiting period
 Sedimentation
 Oxidation
 agglomeration

58. FILTER SAND
COARSE SAND
FINE GRAVEL
COARSE GRAVEL
sand
Sand bed

59. The sand bed presents a vast surface area; one
cubic metre of filter sand presents some
15,000 sq. metres of surface area
The designed rate of filtration of water normally
lies between 0.1 and 0.4 m3/hour/per square
metre of sand bed surface.

60. Vital layer
 Very soon, the surface of the sand bed gets
covered with a slimy growth known as
"Schmutzdecke", vital layer, zoogleal layer or
biological layer.
 This layer is slimy and gelatinous
 The formation of vital layer is known as
"ripening" of the filter

61.  The vital layer is the "heart" of the slow sand
filter.
 It removes organic matter, holds back
bacteria and oxidizes ammonical nitrogen
into nitrates and helps in yielding a bacteria-
free water.
 Until the vital layer is fully formed, the first
few days filtrate is usually run to waste.

62. Under-drainage system
 At the bottom of the filter bed is the under-
drainage
 Filter box:
 Filter box consists from top to bottom:
Supernatant water 1 to 1.5 metre
Sand bed 1.2 metre
Gravel support 0.30 metre
Filter bottom 0.16 metre

63. Filter control
 The purpose of these devices is to maintain a
constant rate of filtration
 An important component of the regulation
system is the "Venturi meter" which
measures the bed resistance or "loss of
head".
 Loss of head exceeds 1.3 mts

64. Filter cleaning
 When the bed resistance increases to such
an extent that the regulating valve has to be
kept fully open, it is time to clean the filter
bed, since any further increase in resistance
is bound to reduce the filtration rate.

65. Advantages
 Simple to construct and operate
 The cost of construction is cheaper
 The physical, chemical and bacteriological
quality of filtered water is very high.
Slow sand filters have been shown to
reduce total bacterial counts by 99.9 to 99.99
per cent and E. coli by 99 to 99.9 per cent.

66. RAPID SAND OR MECHANICAL
FILTERS
 In 1885, the first rapid sand filters were
installed in the USA
 Two types
Gravity type e.g. Paterson's filter
The pressure type e.g. Candy's filter

67. Steps
Coagulation
Alum
Rapid mixing
Violent agitation
Flocculation
Slow & gentle
Sedimentation Filtration

68. Filter beds
 The "effective size" of the sand particles is
between 0.4-0.7 mm.
 The depth of the sand bed is usually about 1
metre .
 Below the sand bed is a layer of graded
gravel, 30 to 40 cm. deep.

69.  The depth of the water on the top of the sand
bed is 1.0 to 1.5 m. The under-drains at the
bottom of the filter beds collect the filtered
water.
 The rate of filtration is 5-15 m3/m2/hour.

70. Filtration
 It forms a slimy layer
 It adsorbs bacteria from the water and effects
purification. Oxidation of ammonia also takes
place during the passage of water through
the filters.
 The filters soon become dirty and begin to
lose their efficiency.

71. Back-washing
 Back-washing dislodges the impurities and
cleans up the sand bed.
 The washing is stopped when clear sand is
visible and the wash water is sufficiently
clear.
 The whole process of washing takes about
15 minutes.

72. Advantages
 Rapid sand filter can deal with raw water
directly. No preliminary storage is needed
 The filter beds occupy less space
 Filtration is rapid, 40-50 times that of a slow
sand filter
 The washing of the filter is easy
 There is more flexibility in operation.

73. DISINFECTION
 Criteria
 It should be capable of destroying the pathogenic
organisms present
 Should not leave products of reaction
 Have ready and dependable availability at reasonable
cost
 Possess the property of leaving residual concentration
 Be amenable to detection by practical, rapid and simple
analytical techniques

74. CHLORINATION
 It is supplement
 Chlorine kills pathogenic bacteria
 Chlorine has several important secondary
properties of value in water treatment

75. Action of chlorine
 H2o + Cl2 HCl + HOCI
HOCI H + OCI
 Chlorine acts best as a disinfectant when the
pH of water is around 7
 It is fortunate that most waters have a pH
value between 6-7.5.

76. Principles of chlorination
 Clear and free from turbidity.
 “Chlorine demand"
The point at which the chlorine
demand of the water is met is called the
"break-point".
 The contact period.
 The minimum recommended concentration
of free chlorine is 0.5 mg/L for one hour

77. METHOD OF CHLORINATION
Chlorine is applied
 Chlorine gas
Patersons chloronome
 Chloramine
 Perchloron- H.T.H

78. SUPERCHLORINATION
 The addition of large doses of chlorine to the
water, and removal of excess of chlorine after
disinfection, this method is applicable to
heavily polluted waters whose quality
fluctuates greatly.

79. Purification of water on a
small scale
 Household purification of water
 BOILING
 CHEMICAL DISINFECTION
 FILTRATION
 Disinfection of wells

80. BOILING
 “rolling boil’’ for 5 to 10 minutes.
 It kills all bacteria, spores, cysts and ova
 Boiling also removes temporary hardness by
driving off carbon dioxide and precipitating
the calcium carbonate

81. CHEMICAL DISINFECTION
 Bleaching powder
 Bleaching powder or chlorinated lime
(CaOCl2) is a white amorphous powder with
a pungent smell of chlorine.
 When freshly made, it contains about 33 per
cent of "available chlorine".
 But when mixed with excess of lime, it
retains its strength; this is called "stabilized
bleach."

82.  Chlorine solution
 If 4 kg of bleaching powder with 25 per cent
available chlorine is mixed with 20 litres of
water- 5% soln of chlorine

83.  High test hypochlorite
 It is more stable than bleaching powder and
deteriorates much less on storage.
 Solution prepared from HTH are also used
for water purification

84.  Chlorine tablets
 They are quite good for disinfecting small
quantities of water, but they are costly.
 The NEERI, Nagpur
 A single tablet of 0.5 g is sufficient to
disinfect 20 lts of water.

85.  Iodine
 Iodine may be used for emergency
disinfection of water.
 A contact time of 20 to 30 minutes is needed
for effective disinfection.
 High costs and the fact that the element is
physiologically active (thyroid activity) are its
major disadvantages

86.  Potassium permanganate
 Once widely used it is no longer
recommended for water disinfection.
 Although a powerful oxidizing agent, it is not
a satisfactory agent for disinfecting water.
 It may kill cholera vibrios, but is of little use
against other disease organisms.
 It has other draw-backs such as altering the
colour, smell and taste of water.

87. FILTRATION
 Pasteur Chamberland filter, Berkefeld filter
and "Katadyn" filter.

88. Disinfection of wells
 The main source of water supply in the rural
areas.
 The most effective and cheapest method of
disinfecting wells is by bleaching powder.

89.  STEPS IN WELL DISINFECTION
 Find the volume of water in a well
V=3.14xd2xh/4x1000
 Find the amount of bleaching powder
required for disinfection - 2.5 grams of good
quality bleaching powder would be required
to disinfect 1,000 litres of water.
 Dissolve bleaching powder in water

90.  Delivery of chlorine solution into the well
 Contact period

91. Hardness of water
 Soap-destroying power of water.
Calcium bicarbonate
Magnesium bicarbonate
Calcium sulphate
Magnesium sulphate
 Chlorides and nitrates of calcium and
magnesium
 Iron, manganese and aluminium compounds

92.  Hardness of water is expressed in terms of
mEq/l.
 One mEq/l of hardness-producing ion is
equall to 50mg CaCO3 in one letre of water
classification Level of hardness
Soft water Less than 1(<50mg/l)
Moderately hard 1-3(50-150mg/l)
Hard water 3-6(150-300mg/l)
Very hard water Over 6(>300mg/l)

93. Disadvantages of hardness of
water
 Consumes more soap and detergents
 Furring or scaling of boilers
 Adversely affect cooking
 fabrics will not have long life
 shortens life of pipes and fixtures

94. Special treatment of water
 Removal of hardness
Temporary hardness
1. boiling
2. addition of lime
3. addition of sodium chloride
4. permutit process
Permanent hardness
1. addition of sodium carbonate
2. base exchange process

95.  Fluoridation
 Defluridation