
Dr. Ravleen Kaur Bakshi
Assistant Professor,
Dept. of Community Medicine,
ABVIMS & Dr. RML Hospital,
New Delhi
WHO Fact Sheet

In 2015, 91% of the world’s population had access to an improved drinking-water source, compared
with 76% in 1990.

2.6 billion people have gained access to an improved drinking-water source since 1990.

4.2 billion people now get water through a piped connection; 2.4 billion access water through other
improved sources including public taps, protected wells and boreholes.

663 million people rely on unimproved sources, including 159 million dependent on surface water.

Globally, at least 1.8 billion people use a drinking-water source contaminated with faeces.

Contaminated water can transmit diseases such diarrhea, cholera, dysentery, typhoid and polio.
Contaminated drinking-water is estimated to cause 502000 diarrheal deaths each year.

By 2025, half of the world’s population will be living in water-stressed areas.

In low- and middle-income countries, 38% of health care facilities lack any water source, 19% do not
have improved sanitation and 35% lack water and soap for hand washing
Water related diseases
Water related disease may be classified as follows:
1. Biological (Water borne disease)
2. Chemical
A: Biological (Water born diseases)
1
Caused by the presence of Diseases
an infective agent
a
Viral
Hepatitis A & E, Poliomyelitis, rota virus diarrhea
b
Bacterial
Typhoid & paratyphoid, bacillary dysentery, E coli,
cholera
c
Protozoal
Amoebiasis, Giardiasis
d
Helminthic
Round warm, threadworm, hydatid disease
2
Presence of aquatic host
Diseases
a
Snail
Schistosmoiasis
b
Cyclops
Guineaworm, fish tape worm
B: Chemical
1
Caused by the presence
of chemicals
Diseases
a
Fluoride
Fluorosis (Mottling of dental enamel)
b
Nitrate
Methaemoglobinemia
2
Due to inadequate use of Diseases
water
a
Inadequate use
Shigellosis, trachoma, conjunctivitis, ascariasis,
scabies
3
Due to insects breeding
in water
Diseases
a
Insects breeding
Malaria, Filaria, arbovirus, African
trypanosomiasis
Water Quality
The guidelines for drinking water quality recommended by WHO
(1993 – 1996) relates the following variables.
1) Acceptability aspects
2) Microbiological aspects
3) Chemical aspects
4) Radiological aspects
Water Quality
Acceptability aspects
1) Physical parameters:
The ordinary consumer judges the water quality by its physical
characteristics .
a) Turbidity:
b) Color
c) Taste and odour
d) Temperature
Water Quality
Turbidity:
 Drinking water should be free from turbidity
 It is caused by particulates matter that may be present as
consequences of inadequate treatment in the distribution
system
 It may also be due to the presence of inorganic particulates
matter in some ground water
 Water with turbidity of less than 5 NTU (Nephelometric
turbidity units) is usually acceptable.
Water Quality
Colour:
 Drinking water should be colourless.
 It may be due to presence of coloured organic matter e.g iron
and magnesium.
 Consumers may turned to alternative perhaps unsafe source
when their water is coloured.
 The guidelines value is up to 15 TCU
Water Quality
Taste and odour:
 It originates from natural and biological sources or from
contamination by chemicals or as a by product of water
treatment (e.g Chlorination).
 It may also develop due to during storage and distribution
 No health based guidelines value is proposed for taste and
odour.
Water Quality
Temperature:
 Cool water is generally more palatable (Acceptable to taste).
 Low water temperature tends to decrease the efficiency of
treatment process, including disinfection and may thus have a
harmful effect on drinking water quality.
 However high water temperature enhances the growth of micro
organisms and taste, colour and corrosion problem may
increase.
 No guidelines value is recommended since its control is usually
impracticable.
Water Quality
 To sum up we can not judge the quality of drinking water by
physical characteristics alone. A detailed chemical and micro
biological examination is also needed for complete
assessment.
Water Quality
Inorganic constituents:
Chlorides:
 All water including rain water contain chlorides
 It is necessary to determine the normal range of chloride
 The standard prescribed for chloride is 200mg/L
 The maximum permissible level is 600mg/L
Water Quality
Inorganic constituents:
Hardness:
 Public acceptability of the degree of hardness may vary
considerably form one community to another, depending on
local conditions.
 The taste threshold for the calcium ion is in the range of 100-
300 mg/L depending on the associated anion and the taste
threshold of magnesium is probably less than that for calcium.
 In some instances water hardness in excess of 500 mg/l is
tolerated by the community.
Water Quality
Inorganic constituents:
Ammonia:
 Ammonia in the environment originates from metabolic agricultural
and industrial processes and from disinfection with chloramine.
 Natural level in ground and surface waters are usually below 0.2 mg/L
 Intensive rearing of farms animals can give rise to much higher levels
in surface water.
 Ammonia can compromise disinfection efficiency results in nitrite
formation in the distribution system & can cause the the failure of
filters for removal of manganese and cause taste & odour problems
Water Quality
Inorganic constituents:
pH:
 Controlling the pH is to minimize corrosion and incrustation in
the distribution system.
 pH level of less than 7 may cause severe corrosion of metals in
distribution system & elevate the level of Lead.
 pH level above 8 there is progressive decrease in the efficiency
of chlorine disinfection process.
 An acceptable pH drinking water is between 6.5 and 8.5.
Water Quality
Inorganic constituents:
Hydrogen sulphide:
 The taste and odour threshold of hydrogen sulphide in water
are estimated to be between 0.05 and 0.1 mg/L
 The rotten egg odour of hydrogen sulphide is a result of oxygen
depletion & subsequent reduction of sulphate by bacterial
activity.
Water Quality
Inorganic constituents:
Iron:
 Anaerobic ground water may contain ferrous iron at
concentrations of up to several mg/L without discoloration or
turbidity in water when directly pumped from the well.
 On exposure to atmosphere the ferrous iron oxidize to ferric
iron giving reddish brown colour.
 Iron also promote the growth of bacteria
 At level above 0.3 mg/L iron stains laundry & plumbing fixtures.
Water Quality
Inorganic constituents:
Sodium, Sulphate and Total Dissolved Solid TDS:
 At room temperature the average taste threshold for sodium is
about 200 mg/L
 It is generally considered that the taste impairment is minimal
at sulphate level below 250mg/L
 The palatability of water with a TDS level of less than 600mg/L
is generally considered to be good.
Water Quality
Inorganic constituents:
Zinc, Magnesium, Copper, Aluminum :
 Zinc taste threshold concentration of 4mg/L
 Magnesium concentration below 0.1mg/L are acceptable
 Staining of laundry and sanitary ware occurs at Copper
concentration above 1mg/L
 The presence of Aluminum at concentration in excess of 0.2
mg/L often leads to deposition of aluminum hydroxide floc in
distribution system and discoloration of water by iron
Inorganic
Permissible Reasons
constituent level
Treatment
Turbidity 5 NTU
Appearance
Filtration
Colour
Appearance
Filtration,
Distillation,
Reverse
osmosis,
Ozonisation
15 TCU
Inorganic Permissible Reasons
constituent level
Treatment
Taste and
odour
------
Should be
acceptable
Activated
carbon, air
stripping,
oxidation,
filtration
Temperature
-------
Should be
acceptable
-------
Inorganic
Permissible Reasons
constituent level
Treatment
Aluminium 0.2mg/l
Deposition, discoloration
Ammonia
Odour &
taste
1.5 mg/l
Algal growth
Inorganic
Permissible Reasons
constituent level
Chloride
250mg/l
Hardness ----------
Treatment
Taste &
----------corrosion
Scale
deposition,
scum
formation,
corrosion
Removed
by ion
exchange,
RO
Inorganic
Permissible Reasons
constituent level
Hydrogen
sulfide
Treatment
Activated
0.05 mg/l Odour
and taste carbon, air
stripping,
oxidation,
filtration
Iron
0.3 mg/l
Staining
Oxidizing
filter
Inorganic
Permissible Reasons
constituent level
Manganese 0.1
staining Ion
exchange,
chlorination,
oxidizing
filter,
mg/l
Dissolved
oxygen
--------
Treatment
Indirect
effects
-----------
Inorganic
Permissible Reasons
constituent level
pH
6.5 – 8.5
Low –
corrosion
High-taste,
soapy feel
Sodium
200 mg/l
Taste
Treatment
Increase
pH- by
soda ash
Decrease
pH – by
citric acid
-------
Inorganic
Permissible Reasons
constituent level
Treatment
Taste,
corrosion
RO,
distillation,
ion
exchange
Sulphate
250 mg/l
Total
dissolved
solids
1000 mg/l Taste
Zinc
3 mg/l
Taste
RO,
distillation,
ion
exchange
same
Water Quality
Microbiological Aspects:
Bacteriological indicator:
 Ideally drinking water should not contain any micro organisms
 Failure to provide adequate protection will expose the
community to outbreaks of water born diseases.
 The primary bacterial indicator recommended for this purpose
is the coliform group of organisms as whole.
Water Quality
Coliform Organisms:
 Coliform organism chosen as indicator of fecal pollution rather
than water borne pathogens directly because;
1. Coliform are constantly present in great abundance in human
intestine. An average person excretes 200-400 bn/day
2. Easily detected by cultural method as small as 1 bacteria in 100ml
3. They survive longer than other pathogens
4. Coliform has greater resistance to the forces of natural
purification than water born pathogens
Water Quality
Fecal Streptococci:
 It regularly occur in feces but in much smaller number than E coli
 Its presence in water is regarded as important confirmatory
evidence of recent fecal pollution of water
Water Quality
Virological Aspect:
 Disinfection with 0.5mg/L of free chlorine residual after contact
period of at least 30 min at pH of 8.0 is sufficient to inactive virus
 This chlorine free residual is to be insisted in all disinfected
supplies area suspected of endemicity of Hepatitis A
Water Quality
Chemical aspect:
 Health risk due to toxic chemicals in drinking water differs from
that caused by micro biological contaminants.
 These substance may be organic or inorganic -
1. Arsenic
2. Cadmium
3. Chromium
4. Cyanide
5. Fluoride
6. Lead, Mercury and Nitrate Nitrite
Inorganic chemicals of health significance in drinking
water
Organic Constituents
Water Quality
Radiological Aspect
 Gross alpha and beta activity are measured
 Radioactivity in drinking water should not only be kept within safe
limit, it should also, within those limits, be kept as low as reasonably
possible.
 The activity of a radio-active material is the number of nuclear
disintegration per unit time. The unit of activity is a Becquerel (Bq); 1
Bq = 1 disintegration per second.
 The proposed guideline value are;
Gross alpha activity 0.1 Bq/L
Gross beta activity 1.0 Bq/L
Bacteriology of water toidentify the
bacterialcontamination
• The bacteriological examination of water is
performed routinely by water utilities and many
governmental agencies to ensure a safe supply of
water for drinking, bathing, swimming and other
domestic and industrial uses.
• The examination is intended to identify water
sources which have been contaminated with
potential disease-causing microorganisms.
How the water getscontaminated
• Such contamination generally occurs either
directly by human or animal feces, or
indirectly through improperly treated sewage
or improperly functioning sewage treatment
systems.
• The organisms of prime concern are the
intestinal pathogens, particularly those that
cause typhoid fever and bacillary dysentery
CommonDiseasesSpreadbyWater
•Typhoid fever
•Cholera
•Diarrhoeal
diseases
•Polio myelitis
•Viral hepatitis A
and E
Contamination Happens
Whenwater comes in Contact
•Faecal matter
•Sewage
contaminatio
n
Bacteriological Analysis ofWater
• Bacteriological water analysis
is a method of analysing water
to estimate the numbers of
bacteria present and, if needed,
to find out what sort of bacteria
they are.
• It represents one aspect of
water quality.
Howthebacteriologicalanalysisofwater
Helps
• It is a microbiological analytical
procedure which uses samples of
water and from these samples
determines the concentration of
bacteria.
• It is then possible to draw
inferences about the suitability of
the water for use from these
concentrations.
1
1
MethodsusedinCulturing of Water
• Analysis is usually performed
using culture, biochemical
and sometimes optical
methods.
• When indicator organisms
levels exceed pre-set
triggers, specific analysis for
pathogens may then be
undertaken and these can be
quickly detected (where
suspected) using specific
culture methods or molecular
biology.
MultipleTube method
• One of the oldest methods is called the multiple
tube method. In this method a measured subsample (perhaps 10 ml) is diluted with 100 ml of
sterile growth medium and an aliquot of 10 ml is
then decanted into each of ten tubes.
• The remaining 10 ml is then diluted again and
the process repeated. At the end of 5 dilutions
this produces 50 tubes covering the dilution
range of 1:10 through to 1:10000.
Methodology of Bacterial analysisof Water
• The tubes are then incubated at a pre-set temperature for a
specified time and at the end of the process the number of
tubes with growth in is counted for each dilution.
• Statistical tables are then used to derive the concentration of
organisms in the original sample.
• This method can be enhanced by using indicator medium
which changes colour when acid forming species are present
and by including a tiny inverted tube called a Durham tube in
each sample tube.
• The Durham inverted tube catches any gas produced.
• The production of gas at 37 degrees Celsius is a strong
indication of the presence of Escherichia coli.
Multiple tubeMethods
LaboratorypicturesshowhowtheWateris
Analysed
Membranefiltration
• Most modern laboratories use a refinement of total
plate count in which serial dilutions of the sample
are vacuum filtered through purpose made
membrane
filters and these filters are
themselves laid on nutrient medium within
sealed plates.
• The methodology is
otherwise similar to
conventional total plate counts.
• Membranes have a printed millimetre grid printed
on and can be reliably used to count the number of
colonies under a binocular microscope.
PLATECOUNT
• Test of water contamination in which the number of
the colonies of coliform-bacteria Escherichia coli
(E. coli) per 100 milliliter of water is counted. The
result is expressed as
'Coliform Microbial
Density' and indicates the extent of fecal
matter present in it.
• According to common water quality standards
drinking water must be completely free from any
colony, bathing and swimming pool water can have
about 200 colonies, and recreational (fishing and
boating) water about 1000 colonies.
Reporting the Results ofWater
Analysis
• When a water
sample arrives at
the laboratory, two
tests, the plate
count and the
coliform test by the
multiple tube
method, are made
and reported
2
3
ReportingtheResultsofWaterAnalysis
• The coliform test actually
consists of two steps known
as the presumptive test and
the confirmed test.
Under certain conditions, it is
necessary to go one step
further and make a
completed test;
however, this step is not
always necessary.
To
make the tests, small portions
of the water sample are used
in accordance with the
following procedures.
The PlateCount
• The plate count is a test made
by the laboratory to determine
the total number of bacteria
present in the sample. This test
does not differentiate between
the many different types of
bacteria and is thought of as
giving index to the general
"housekeeping" practices. A
"high" count indicates that some
type of contamination is present
and is undesirable.
• The test is made by
placing a portion of agar in
a petri dish.
Public HealthConcept
• The coliform group
has been used
extensively as an
indicator of water
quality and has
historically led to the
public health
protection concept.
Detection ofVirus
• Methods are available for isolation of Enterovirus
and other cytopathogenic viruses from water
• But are not part of routine tests unless
epidemics happens
• However Viruses are destroyed with
Chlorination of water
• The Free residual chlorination is at least 0.5 mg
per litre for a contact period of 30 minutes at ph.
below 8
Protozoa inWater
• Endamoeba histolytica
• Giardia species
• Balantidium coli
• However there are no
specific tests
• Coliforms are not reliable
as indicators of protozoal
contamination

RAIN WATER HARVESTING
 Rain water is the ultimate source of fresh water
 Potential of rain to meet water demand is tremendous
 Rain water harvesting helps to overcome water
scarcity
 To conserve ground water the aquifers must be
recharged with rain water
 Rain water harvesting is the ultimate answer
Rain Water Harvesting…..
• Rain Water Harvesting RWH- process of collecting,
conveying & storing water from rainfall in an area – for
beneficial use.
• Storage – in tanks, reservoirs, underground storagegroundwater
• Hydrological Cycle
RWH – Methodologies
•Roof Rain Water Harvesting
•Land based Rain Water Harvesting
•Watershed based Rain Water harvesting
For Urban & Industrial Environment –
Roof & Land based RWH may be used in
• Public, Private, Office & Industrial buildings
• Pavements, Lawns, Gardens & other open
spaces
Rain Water Harvesting– Advantages
1.Provides self-sufficiency to water supply
2.Reduces the cost for pumping of ground water
3.Provides high quality water, soft and low in minerals
4.Improves the quality of ground water through
dilution when recharged
5.Reduces soil erosion & flooding in urban areas
6.The rooftop rain water harvesting is less expensive
& easy to construct, operate and maintain
7. In desert, RWH only relief
8. In saline or coastal areas & Islands, rain water
provides good quality water
Appropriate Technology
Water conservation
and groundwater
recharge techniques
Water harvesting cum
supplementary
irrigation techniques
Thank You
Email – drravleen01@gmail.com