Water is a vital necessity of life without which man can live only for few days. About two thirds of our body weight is formed of water.

1. WATER SANITATION
Dr. Dalia El-Shafei
Ass.Prof of Occupational Medicine

3. Natural water Supplies
Surface water
River & lacks
Easily
polluted so
needs
purification.
Underground water
2 layers:
shallow &
deep
Sterile if
sanitary
precautions
are followed
Rain water
Pick
impurities
Spring
Pure if
protected
Sea water
Desalination
is expensive

5. Large
scale
Small
scale
• Water intake
• Coagulation-sedimentation
• Filtration
• Disinfection “Chlorination”
• Distribution
• Boiling
• Filtration
• Disinfection

6. Water
intake
• Place selected in the course of river or (canal) to draw water for purification
• Must be protected & away from any source of pollution especially fecal materials.
Coagulation-
sedimentation
• Water is pumped from intake to sedimentation tanks & left for some hours so that greater part of suspended
matter settles down.
• For better sedimentation in a shorter period of time, a coagulant (commonly alum) is added
Filtration
• Mechanical sand filter made of layers of sand on top of gravel.
• Alum & rest of impurities form a surface film, which is responsible for the filtration process.
Water gets filtered on passing through the surface film. Removes all bacteria, cysts and
suspended matter but virus can pass through the filter. Max. efficiency of filtration for micro-
organism removal is 95%.
• Frequent washing of the filter is needed by passing a reverse current of water under high
velocity.
Disinfection
• Necessary to destroy the remaining 5% pathogenic organisms that may be found in filtered water. Chlorine is
the gas commonly used in disinfection.
• Chlorine is added to filtered water in a proper dose “0.6 ppm“& left for ½ an hour.
• Residual chlorine “0.2 ppm” is to safe guard against pollution during distribution of water to final consumers.
• Super chlorination of water occur in cases of water borne epidemic.
Distribution
• Through a network of pipes, water is distributed to the different parts of the areas to
be supplied. Presence of residual chlorine in water is a safeguard against
contamination from breaking or leaking through pipes

10. Boiling
• Reliable method.
• Kills all pathogens
• Specially needed for
preparing bottle feeding
of young infants.
Filtration
•Domestic filter is the
simplest.
•Water passes through a
candle, which is made of
clay, porcelain.
•Requires regular
cleaning & if not properly
cared for, it may become
a source of infection itself
Disinfection
•Chlorine of lime
(bleaching powder). It
contains 20-35 % of its
weight available chlorine.
• Destroys most of
microorganisms if proper
dose & contact time are
allowed.
Small Scale purification: used in villages, small confined areas. It is
used for water supply at the individual levels in case of absence of
large-scale purification

12. 1- River water:
- A popular source where people go to the canal to fill utensils.
- They used for domestic purposes without purification and may be
kept in porous containers (e.g. zeer, kolla) for cooling purpose not
for purification.
- Water is unsafe and thus can expose consumers to infection.

13. 2-Shallow wells:
- Used by some houses for private water supply.
- Shallow underground water, which is located in the superficial layers
of the soil, is raised to the surface by a pump.
Advantages:
Bacteriologically safe if sanitary measures are taken.
Disadvantages:
- Exposed to pollution, from the surface & nearby sources (latrines,
cesspits & refuse heaps) with the risk of spreading water-borne
infection.
- Potential sources of pollution must be eliminated with an area of 20
meters radius all around the well.
- A shallow well is 1st licensed after sending water sample for lab
analysis & should be continuously licensed to ensure safety.

15. 3- Deep wells:
- Underground water in the deep layers is obtained by constructing a deep well at a
depth of more than 20 meters to reach the deep underground water layer.
- Pumped water is raised up to fill a high tank reservoir of suitable size.
- Water is distributed from the tank to a number of public taps located at different
spots of the village.
Advantages:
- Deep water is clear, but not tasty, it is hard (not forming foam with soap).
- Bacteriologically sterile but pollution is possible through cracks or leakage through
pipes.
Disadvantages:
In certain localities, deep underground water contains excess chemicals, from strata of
earth, which may cause:
*Dental fluorosis: Excess fluorine (>1.5 ppm) causes mottling of the enamel of teeth.
*Methemoglobinaemia: Excess nitrates (>20 ppm) lead to the formation of nitrites
which is absorbed, and affects Hb leading to a serious and fatal disease in infants.

18. Physical
BiologicalChemical
Water examination for physical, chemical & bacteriological
standards is carried out at each step of water purification.

19. Physical standards:
- Must be odorless, colorless, agreeable taste and clear.
- Presence of organic matter, algae, silt and mud can alter
water's physical characteristics (becomes turbid, changes
odor) but not necessarily cause harm.

20. Chemical standards:
- pH must be neutral or slightly alkaline.
- With a moderate degree of hardness. Hardness is
the presence of insoluble salts of calcium &
magnesium in water. It can cause GIT
disturbance, waste of soap and explosion of
boilers. It is removed by boiling, addition of lime
or precipitation. Permissible hardness is 20
degrees.
- Safety limits for some chemicals are determined
such as nitrate 1.0 ppm, fluoride 1.5 ppm, iron
0.3 ppm, arsenic & lead must be nil.

22. Bacteriological standards:
- It concentrates on evidence of faecal pollution.
- Water is inoculated on agar & other special media.
- Coliform organisms are used as indicators for presence of bacteria.
- A high coliform count of ≥ 100 ml is regarded as being suspicious of
fecal pollution.
- E. coli must be totally absent. No ova, no cysts or parasites.

24. Water pollution is any physical, biological &
chemical changes in water quality that adversely
affects living organisms (man, animal and fish) or
make water unsuitable for desired uses

25. • Bacteria: enterica, cholera, dysentries
• Viruses: hepatitis, poliomyelitis.
• Parasites: Gardia, schistosomiasis. entamebahistolytica.
Biological
• Acids, Salts, Mercury and Lead
• Minamata disease caused by mercury intoxication.
Water soluble
inorganic chemicals
• Pesticides & OilsOrganic chemicals
• Organic wastes decomposed by bacteria which deplete
water from its oxygen thus causing death of fish &
aquatic plants.
Oxygen demanding
wastes
• Insoluble particles that are suspended and thus cloud
water and reduce photosynthesis of aquatic plants.
Sediment or
suspended matter
• Cause birth defects, cancer, genetic damage.
Radioactive
isotopes

27. - Sudden or explosive onset.
- Large number of cases is reported in few days.
- All cases having common water supply.
- All ages, both sexes and different social groups are affected.
- More than one case may be simultaneously found in same family.
- May occur in any season.
-Cases of diarrhea & other GIT manifestations may appear before
epidemic wave due to associated infection with other pathogenic
organisms of shorter IP.
-When water supply is controlled cases drop suddenly but take time to
return to the pre-epidemic level due to occurrence of 2ry cases.

29. Control of water borne epidemic:
1. Control of the water source that caused the epidemic.
2. Increase the amount of chlorine added to the water & then neutralize
the excess.