The hygienic aspects

of the organization
of water supply
in the settlements

Lector
Associate Professor
Ekaterina Shashina
 SYSTEM OF HYGIENE MEASURES TO
ENSURE THE DRINKING WATER SUPPLY

Providing water consumption

norms
Rational choice of water
source
The establishment of zones
of sanitary protection of water
sources
Maintaining the technology of
drinking water treatment
Standardization of water
quality
The principles of water source choice

The water quality in the

source (the constancy
of composition, ability
to cleanse itself,
organoleptic properties)

The possibility of
Debit - the flow
extraction and
rate of source
purification of
(m3/h)
water
Sources of centralized economic-
drinking water supply

• Underground and ground water

• Surface water
Underground and ground water
 Characteristics of the
underground water
Underground sources have several advantages:
• they are more protected from anthropogenic
pollution;
• they have stable bacterial and chemical
composition.
The formation of water quality in these sources
depends on the following factors: climate,
geomorphological structure of soil, the nature of
the vegetation (lithological structure).
 Surface water sources
• Rivers
• Lakes
• Reservoirs
(water storage basin)
Characteristics of the surface
water
They have a huge amount of water - a high
production rate (debit)
They are poorly mineralized (from north to south
water in the different sources is characterized by
an increase in total mineralization)
They are enriched with humic substances
They are subject to significant anthropogenic
pollution
The species composition of microflora sharply
increases
The rules of selection of sources of
water supply
• Water quantity in the source
• Water quality in the source
The order of the water source selection, taking into
account their quality:
interstratal artesian water (flowing artesian well)
interstratal non-pressure water (non-flowing
artesian well)
Groundwater
Surface water
CONSTRUCTION OF A DUG WELL

1. lid
2. well parapet (0,8 m)
(headstall)
3. blind area from stone, brick,
concrete, asphalt
4., 6. trunk
5. "lock" from thoroughly
compacted clay (2 m x 1 m)
7. solid, good insulated bottom
8. round or square wells (for
water)
 SANITARY PROTECTION ZONES OF
WATER SOURSE
place of water
intake

river

1st zone -
3rd zone - 2nd zone - Protection Protection
Protection against microbial against sabotage
against contamination
microbial
contamination
 Standardization of water quality

Maximum Contaminant Level (MCL)

is the concentration of substance with cannot
be exceeded without the water becoming
unsuitable for one or more types of its
intended uses.
 Critical indicator of harm (CIH)
is one of the features of harmfulness of
chemical pollutants of water that
determines the prevailing unfavorable
effect and is characterized by the lowest
value of efficient concentration.
is established in the experiment.
 Critical indicator of harm
Indicator Prevailing effect
name
Sanitary and direct or indirect unfavorable
toxicological influence on the state of human
health of present and future
generations
Organoleptic influence on organoleptic properties
of water (odor, taste, color)
General influence on the process of self-
sanitary cleaning of water in reservoirs
Example: Test chemical
• acts on kidneys (i.e. direct unfavorable influence
on the state of human health)
• at concentration 0.08 mg/L,
• changes the taste of water at concentration 1.2
mg/L,
• acts on the microorganisms in the reservoir at
concentration 3 mg/L.
Critical indicator of harm - sanitary and
toxicological
MCL -  0.08 mg/L
 Effect of summation
It’s considered for substances of class 1 and 2 with
the same limiting hazard indicator

С1 + С2 + С3 + . . . + Сn must be  1
MCL1 MCL2 MCL3 MCLn

For example,
concentration of nitrates is 40 mg/L, it does not exceed MCL (45
mg/L)
concentration of nitrites is 2 mg/L, it does not exceed MCL (3 mg/L)

40 + 2 = 1.6 ( 1, such mixture is harmful)

45 3
 GENERAL REQUIREMENTS TO ALL
WATER SOURCES

Dry residue (total mineralization) - no more than 1000 mg/L

Chlorides concentration - no more than 350 mg/L

Sulfates concentration - no more than 500 mg/L

Total hardness - no more than 7 mg-eq/L

 Quality standard of water in the
underground water sources
Indicator 1-st class 2-nd class 3-rd class
Turbidity, mg/L  1,5  1,5  10
Color, degree  20  20  50
pH 6-9 6-9 6-9
Fe, mg/L  0,3  10  20
Mn, mg/L  0,1 1 2
H2S, mg/L 0 3  10
F, mg/L 1,5 – 0,7 1,5 – 0,7 5
Oxidability, mgO/L  2  5  15
The number of
coliform bacteria in
dm3 of water 3  100  1000
Water treatment for different classes of
underground water sources
1st class – water quality is the best,
corresponds to the quality standard of the
drinking water. Additional treatment is not
needed.
2nd class – aeration, filtration, disinfection.
3rd class - aeration, filtration, disinfection
with additional chemical reagents, filtration
with sedimentation.
 Quality standard of water in the surface
water sources
Indicator 1-st class 2-nd class 3-rd class
Turbidity, mg/L  20  1500  10 000
Color, degree  35  120  200
Odor, point 2 3 4
pH 6,5 – 8,5 6,5 – 8,5 6,5 – 8,5
Fe, mg/L 1  3  5
Mn, mg/L  0,1 1 2
Phytoplankton, mg/L 1 5  50

Oxidability, mgO/L  7  15  20
The number of lactose-
positive coliform bacteria in 1  1000  10000  50000
dm3 of water
Water treatment for different classes of
surface water sources
1st class – disinfection, filtration with
coagulation.
2nd class – coagulation, sedimentation,
filtration, disinfection, microfiltration (if
biofilm present).
3rd class - coagulation, sedimentation,
filtration, disinfection, microfiltration (if
biofilm present). Additional: clarification,
oxidation, sorption, more effective method
of disinfection.
 Quality standard of water
in the drug well
Indicator Standard
Color, degree  30
Odor, point 2-3
Taste, point 2-3
Hardness, mg-eq/L 7 - 10
Total mineralization, mg/L 1000 - 1500
Oxidability, mg/L 5-7
Total bacterial count  100
Other indicators are the same as in the
drinking water
WATER TREATMENT
 Basic scheme to improve water quality
Requirements to
water from source
Special
Source Filtration methods of
water water
treatment

Disinfection
Coagulation
Distribution
tap network

Sedimentation Filtration Requirements

to drinking
water
Scheme to improve water quality
1. Coagulation, flotation, and sedimentation –
remove colloids, suspended solids, and some
macro-organisms.
Reagents: Al2(SO4)3, FeSO4, FeCl3,
Powdered activated carbon, Polyacrylamide

2. Pre-ozonation (O3) - kills microorganisms,

removes odor and unpleasant taste, color,
prevents the formation of by-products in the
subsequent disinfection.
 Scheme to improve water quality
3. Filtration - removes remaining suspended
solids, bacteria and organic compounds that can
support the growth of biofilms (mucus).

4. Disinfection - kills microorganisms and reduces

the possibility of formation of biofilms.
 Disinfection
Methods

Chemical Physical

Strong oxidizers: Boiling, ultraviolet

chlorine, ozone, silver, irradiation
iodine, manganese,
bromine
 Cl2 + H2O = HOCl + HCl
HOCl = H+ + OCl-
(HOCl + OCl-) - residual free chlorine

Indicator of disinfection efficiency

0.3 - 0.5 mg/L residual free chlorine
0.8 - 1.2 mg/L residual bound chlorine
<< >>
Ineffective disinfection Irritant effect on the body
- repeat disinfection – repeat filtration
CHLORINATION DISADVANTAGES

Problem with transportation and storage

High stability of the formed chlorine compounds
Formation of toxic and carcinogenic organic
chlorine compounds
Accumulation of these compounds in aquatic
organisms
Corrosion of plumbing
Chloramine treatment
Water treatment with chloramine
minimizes (prevents) the formation
of disinfection by-products
(chlorine compounds)
 OZONIZATION ADVANTAGES

Effectively removes odor

Effectively removes organic substances
(in conjunction with the filter)
Reduces mutagenicity
Removes dissolved organic carbon (medium for
biofilm)
Reduced dose of chlorine
 Conditions and the effectiveness of water
disinfection with ozone (О3)
Bacteria Virus
О3 concentration 0,5-1,5 mg/L 1-2 mg/L

Residual О3 0,1-0,2 mg/L 0,4 mg/L

concentration (after 5 (after 4
minutes) minutes)
Processing time 5 minutes 8 minutes

Effectiveness 99,9% 99,9%

Indicator Method of water treatment
not corresponding to the
requirements
Turbidity Clarification - coagulation,
sedimentation, filtration
Iron Deferrization (deironing)
Fluorine Fluorination, defluorination
The mineral composition Desalination
Hardness Softening
Odor Deodorization
Radioactive substances Deactivation
 The effectiveness of water treatment at
traditional waterworks
High Moderate Absence Deterioration

Common Oxidability Salt composition Aluminum

microbial Iron Heavy Residual chlorine
number Manganese metals Trihalomethanes
Coli index Petroleum Indicators of and others
Salmonella products corrosion halogen-
Helminths Synthetic activity containing
Chromaticity surfactants Nitrogen hydrocarbons
Turbidity Viruses connection Mutagenic
Benzo(a) pyrene Coli-phages Radionuclides activity
Clostridium Toxic Formaldehyde
cyanobacteria Toxicity for
hydrobionts
 High-performance innovative technologies
making new quality water
Method Characterization

Ozonosorption - water Water better cleaned of

treatment with ozone with chemical contamination,
additional filtration through a eliminates unpleasant odors
granulars of activated and flavors, there is a partial
carbon. disinfection.
Membrane ultrafiltration - Removal of viruses, bacteria,
water under pressure is large organic molecules.
passed through a
microporous polymer
membranes with a pore size
of 0.01 microns.
 Bottled water

water source

Bottled water
sandy filter UV lamp sorption filter

secondary filter

clean
drinking
water silver generator
unit dosing of salts reverse osmosis
Drinking-water quality requirements

Water must be epidemically

and radiation safe.
Water must be harmless in
chemical composition.
Water should have
appropriate organoleptic
properties.
Epidemic safety of drinking water
Thermotolerant coliform bacteria - an
indicator of fresh fecal pollution.
Standard – 0 in 100 ml of water.
Total coliform bacteria - thermotolerant
coliform bacteria and E. coli - an
indicator of organic substances of
human origin, including fecal.
Standard - 0 in 100 ml of water.
Сoli index – the number of coliform
bacteria in 1 liter of water - 3.
Coli titre – the quantitative of water
that contains one E. coli -  300 ml.
Escherichia coli – indicator bacterial
pollution of water
 Epidemic safety of drinking water

Total bacterial count - used to control the

quality of water treatment.
Standard - no more than 50 colony-forming
bacteria in 1 ml of water.
Monitored over time. If the standard is not
respected - a danger signal - violations of
water treatment technologies.
Epidemic safety of drinking water

Coliphages - viruses of E.Coli –

an indicator of viral
contamination.
Standard - 0 in 100 ml of water.

Giardia cysts - an indicator of

water safety in parasitic regard.
Standard – 0 in 50 ml of water.
Epidemic safety of drinking water
Sulphite-reducing clostridia
spores - sanitary-indicative
microorganisms. Spores have
great survivability in water and
resistant to disinfectants.
Is defined as an indirect indicator
of the effectiveness of cleaning of
surface water sources from
resistanced to decontaminate
enteric viruses and parasitic
protozoa.
Standard – 0 in 20 ml of water.
The causes of gastrointestinal diseases
connected with the use of water
Lack of water treatment

Failures in the wastewater treatment plants

Concentration of disinfectant residuals is below

the standard (concentration of HOCl + OCl is
low than 0.3 mg/L)

Sewage pollution accidents through cracks in

the pipes, the choke when using hoses and
hydrants
 The criteria of chemical
harmlessness of drinking water
Indicator MCL (CIH)
Total mineralization, mg/L  1000
Chlorides, mg/L  350 (org)
Sulfates, mg/L  500 (org)
Total hardness, mg-eq/L  7
Phenol index  0.25
Iron, mg/L  0.3 (org)
MCL – maximum contaminant level,
CIH - critical indicator of harm. Definitions see above
 The criteria of chemical
harmlessness of drinking water
Indicator MCL (LHI)
Cadmium, mg/L  0.001 (s-t)
Lead, mg/L  0.03 (s-t)
Arsenic, mg/L  0.05 (s-t)
Strontium, mg/L  7 (s-t)
Molybdenum, mg/L  0.25 (s-t)
Chromium, mg/L  0.05 (s-t)
Cuprum, mg/L  1 (org)
 The criteria of chemical
harmlessness of drinking water
Indicator MCL (CIH)
Manganese, mg/L  0.1 (s-t)
Zinc, mg/L  5 (org)
Chloroform  0.2 (s-t)
2,4-D  0.03 (s-t)
Petroleum products  0.1
Surface active agents  0.5
 Standard for fluoride depends
on climate zone
Climate zone Standard for fluorine
I (north)  1.5 mg/L
II  1.5 mg/L
III  1.2 mg/L
IV (south)  0.7 mg/L
 Standard for nitrate compounds
Nitrate compound MCL (CIH)
NН4+  1,5 - org (odor)
NO2-  3 - s-t
NO3-  45 - s-t

When the nitrates and nitrites present together in

the water, it should be taken into account the effect
of the summation (see formula above)
 Criteria of radiation safety of
drinking water
Indicators Units Standard Сritical
indicator
of harm
General Bq/L 0,1 radiation
-radioactivity
General Bq/L 1,0 radiation
-radioactivity

* Bq/L – Becquerel per liter

 QUALITY CRITERIA OF
DRINKING WATER

Organoleptic
properties are water
quality indicators
perceptible by human
receptors: odor, taste,
color, turbidity.
 Turbidity
Turbidity is microscopic ultrafine
suspended particles.
There are the majority of the sorbed
viruses on the surface of suspended
particles.
The main negative consequence of high
turbidity is that it protects microorganisms
under ultraviolet disinfection and
stimulates bacterial growth.
Therefore, water turbidity is not only a
organoleptic property of water, but also an
indirect indicator of epidemiological safety.
The appearance, taste and odor of
drinking-water should be acceptable to
the consumer.
The standards for organoleptic
indicators

Indicator Norm
Odor 2 points
Taste 2 points
Color 20 degree
Turbidity 1,5 mg/L
pH 6-9
 Chemicals, that change
organoleptic properties of water
Odor Taste Color
Ammonia Sulfates (bitter) Iron
Residual chlorine Chlorides (salted) Zinc
Iron Iron (ferrous) Copper
Polyphosphate Manganese
(sweet)
"Water! You have no taste, no smell, no color, you can not
be described; we enjoy you, not understanding what you
are. You do are not only necessity, you are the life ... you
are the greatest wealth in the world ...“ A.Sent-Exupery