In 2010, the UN General Assembly explicitly recognized the human right to water and sanitation. Everyone has the right to sufficient, continuous, safe, acceptable, physically accessible, and affordable water for personal and domestic use. Sustainable Development Goal target 6.1 calls for universal and equitable access to safe and affordable drinking water. The above target is tracked with the indicator of “safely managed drinking water services” - drinking water from an improved water source that is located on-premises, available when needed, and free from fecal and priority chemical contamination.

1. WATER SUPPLY AND
TREATMENT TECHNOLOGY
(EHT 215)
LECTURER: SIR OAK

2. LECTURE ONE
 General knowledge in water
Learning objective:
After completing this topic, students should be able to:
• have a critical understanding of water, sanitation and hygiene
interventions
• appreciate the need of water in promoting health.

3. Introduction
 Water is a chemical compound of two atoms of hydrogen (H)
and one atom of oxygen: H - O - H
 Liquid water covers about three-quarters (3/4) of the surface of
the earth, providing us with oceans, lakes and rivers. Immersed
aquifers stored water deep underground. Ice dominate the vast
polar regions of the globe. It appears icebergs on the ocean and
it whitens the temperate zones as snow and winter.
 Safe and readily available water is important for public health,
whether it is used for drinking, domestic use, food production or
recreational purposes.

4. Introduction cont…
• In 2010, the UN General Assembly explicitly recognized the
human right to water and sanitation.
• Everyone has the right to sufficient, continuous, safe,
acceptable, physically accessible, and affordable water for
personal and domestic use.
• Sustainable Development Goal target 6.1 calls for universal and
equitable access to safe and affordable drinking water.
• The above target is tracked with the indicator of “safely
managed drinking water services” - drinking water from an
improved water source that is located on premises, available
when needed, and free from faecal and priority chemical
contamination.

5. Introduction cont…
• The long-term vision of the Government of Ghana is universal
access to safe drinking-water by 2025 and to eliminate open
defecation by 2030 in line with the SDGs.
• The above vision finds expression in the:
Water Sector Strategic Development Plan (WSSDP),
2012–2025.
Ghana Shared Growth and Development Agenda (GSGDA),
2014–2017.

6. Key facts about water (WHO, 2019)
• In 2017, 71% of the global population (5.3 billion people) used a
safely managed drinking-water service – that is, one located on
premises, available when needed, and free from contamination.
• 90% of the global population (6.8 billion people) used at least a
basic service. A basic service is an improved drinking-water
source within a round trip of 30 minutes to collect water.
• 785 million people lack even a basic drinking-water service,
including 144 million people who are dependent on surface
water.

7. Key facts about water cont…
• Globally, at least 2 billion people use a drinking water source
contaminated with faeces.
• Contaminated drinking water is estimated to cause 485 000
diarrhoeal deaths each year.
• By 2025, half of the world’s population will be living in water-
stressed areas.
• In least developed countries, 22% of health care facilities have
no water service.

8. Key facts about water cont…
• Safe water combined with adequate sanitation and hygiene could
result in a substantial reduction of the 5million deaths due to
diarrhea diseases that occur each year.
• Water is both the most abundant and the most important
substance which nature provides to sustain life for plants and
animals.
• Water is an indispensable natural resources and that there is no
substitute for it and its uses.
• Its availability is limited while its overall demand per capital has
increased considerably due to population explosion and the
increasing sophistication of people.

9. Sources of water supply
There are three (3) main sources of water supply; namely:
• Rain water: Snow, Hail, Dew, Fog, Sleet.
• Surface water: Rivers, Lakes, Dams, Lagoons, Streams, ponds.
• Ground water: Wells, Springs
NB: The ocean and sea amount to about 97% of the waters of the earth. 3% is
made up of fresh water. Out of the fresh water 0.8% is accessible to man.

10. Sources of water supply cont…
• Sources of water can be grouped into three (3) main
categories, namely:
Wholesome water: springs, up-land surface water.
Suspected water: stored rainwater, pond water.
Polluted water: river connected with sewers, water from farms.

11. Characteristics of water
• Pure water is neutral to litmus paper.
• It tends unhydrous CuSO4 from white to blue.
• Pure water attains highest density of 1000kg/m3 at 40 C
• Pure water freezes at 00 C
• Pure water boils at hundred 1000 C
• Pure water is colourless, tasteless and odourless

12. Characteristics of water cont…

13. Surface properties of water
• A needle floats if place upon the surface of water but it sinks
immediately if it breaks through the surface. Apparently, the
surface of water acts like a skin.
• The molecules within the liquid completely surrounded by a
hydrogen bounded to adjacent water molecules. At the surface
of the liquid however, water molecules experience an uneven
attraction.
• The inward force or pull which tends to minimize the surface
area of a liquid is called surface tension.

14. Classification of water
There are two kinds of water, namely; soft and hard water.
• Soft water: lathers easily with soap
• Hard water: does not lather easily with soap. That is, it forms
scum with soap
NB: There are also two kinds of hard water, namely: permanent
and temporally hardness.

15. Assignment - I
1. With clear examples, differentiate between temporal and
permanent hard waters.
2. Suggest possible ways of treating both temporal and
permanent waters.
3. Outline three (3) demerits of hard water.

16. Uses of water
 Physiological uses of water
i. It has been estimated that for minimum human existence, one
needs between 20 and 50 litres of water per day for drinking,
personal hygiene, preparation of food, etc.
ii. Water is a component of life and so serves as a medium for
catabolic and metabolic activities in both plants and animals.
iii. It serves as a habitat for many life forms including viruses,
bacterial, plants, etc.

17. Uses of water cont…
 Anthropological and economic uses of water
i. Water influences the choice of site for settlement and setting up of
industries.
ii. Navigable water ways are sources of transportation.
iii.Waterfalls, natural lakes and beaches are tourist attractions.
iv. For agricultural purposes and the production of hydro-electrical
power.

18. Impurities in water.
Pure water does not exist in nature. This is because of:
Absorption of dust particles and micro-organisms in air and
at the ground surface.
Dissolution of oxygen, carbon dioxide and other gasses.
Absorption of products of organic matter decomposition.
Dissolution of salt.

19. Common impurities in water and their effects
Impurities Effects
Bacteria Some cause disease eg. salmonella
Algae Odour/colour/turbidity
Protozoa Odour/colour/turbidity
Silt Turbidity
1. Suspended impurities

20. 2. Dissolved impurities
Impurities Effects
Ca & Mg salts – Ca(HCo3) Alkalinity, hardness.
CO3 (Carbonate) Alkalinity, hardness.
SO4 (Sulphate) Hardness.
CL- (Chloride) Hardness, corrosive to boiler

21. 3. Sodium salts (Na)
Impurities Effects
HCO3 (Bicarbonate) Alkalinity & Softening effect
CO3 (Carbonate) Alkalinity & Softening effect
Fluoride Mottled enamel of teeth
Chloride Taste

22. 4. Others
Impurities Effects
FeO (Iron oxide) Taste, red water, corrosive to
metals & hardness.
Mn (Manganese) Black or brown water
Vegetable dynes Colour and acidity

23. 5. Gasses
Impurities Effects
Oxygen (O2) Corrosive to metals
Carbon dioxide (CO2) Corrosive to metals & acidity
Hydrogen Sulphide (H2S) Odour, acidity & corrosive to
metals.

24. Water and health
• Contaminated water and poor sanitation are linked to
transmission of diseases such as cholera, diarrhoea, dysentery,
hepatitis A, typhoid, and polio.
• Absent, inadequate, or inappropriately managed water and
sanitation services expose individuals to preventable health
risks.
• Inadequate management of urban, industrial, and agricultural
wastewater means the drinking-water of hundreds of millions of
people is dangerously contaminated or chemically polluted.

25. Water and health cont…
• 297, 000 children aged under 5 years die each year as a result
of unsafe drinking-water, sanitation, and hand hygiene.
• Where water is not readily available, people may decide
handwashing is not a priority, thereby adding to the likelihood of
diarrhoea and other diseases.
• Insects that live or breed in water carry and transmit diseases
such as dengue fever. Some of these insects, known as
vectors, breed in clean, rather than dirty water, and household
drinking water containers can serve as breeding grounds.

26. Economic and social effects of water
• When water comes from improved and more accessible sources,
people spend less time and effort physically collecting it, meaning
they can be productive in other ways.
• This can also result in greater personal safety by reducing the
need to make long or risky journeys to collect water.
• Better water sources also mean less expenditure on health, as
people are less likely to fall ill and incur medical costs, and are
better able to remain economically productive.
• Access to improved sources of water can result in better health,
and therefore better school attendance for children.

27. The task
What role can Environmental Health Professionals play to ensure
that people have access to safe water located on their premises,
available when needed, and free from contamination?

29. Thank you.