Вода и здоровье” ( лекция для англоязычных студентов 3- го курса ммф ) Лекцию подготовил доцент кафедры гигиены и экологии Клименко А. И icon

Вода и здоровье” ( лекция для англоязычных студентов 3- го курса ммф ) Лекцию подготовил доцент кафедры гигиены и экологии Клименко А. И




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НазваВода и здоровье” ( лекция для англоязычных студентов 3- го курса ммф ) Лекцию подготовил доцент кафедры гигиены и экологии Клименко А. И
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ТипЛекция
1. /Module1. General questions of Hygiene and Ecology/Lectures/Children and adolescent hygiene.rtf
2. /Module1. General questions of Hygiene and Ecology/Lectures/Health and Environment.rtf
3. /Module1. General questions of Hygiene and Ecology/Lectures/Introduction to hygine.rtf
4. /Module1. General questions of Hygiene and Ecology/Lectures/Nutrition and health. Bolonian..rtf
5. /Module1. General questions of Hygiene and Ecology/Lectures/Occupation and health Bolonian.rtf
6. /Module1. General questions of Hygiene and Ecology/Lectures/Water and health.rtf
7. /Module1. General questions of Hygiene and Ecology/Practical studies/Compl. infl. of microclimate/Complex microclimate assessment. doc.doc
8. /Module1. General questions of Hygiene and Ecology/Practical studies/Compl. infl. of microclimate/Topic 08.doc
9. /Module1. General questions of Hygiene and Ecology/Practical studies/Dust and chemic.admix/Dust. doc.doc
10. /Module1. General questions of Hygiene and Ecology/Practical studies/Dust and chemic.admix/The methods of air sampling.doc
11. /Module1. General questions of Hygiene and Ecology/Practical studies/Dust and chemic.admix/Topic 12.doc
12. /Module1. General questions of Hygiene and Ecology/Practical studies/Food poisoning/Food pois.doc
13. /Module1. General questions of Hygiene and Ecology/Practical studies/Hygiene of children/mannual 1.doc
14. /Module1. General questions of Hygiene and Ecology/Practical studies/Hygiene of children/mannual 2.doc
15. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/Hygienic estimate of insolation regimen.doc
16. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/Natur. ill. doc.doc
17. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/SOLAR RADIATION AND ITS HYGIENIC IMPORTANCE.doc
18. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/Topic 04.doc
19. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/Topic 05.doc
20. /Module1. General questions of Hygiene and Ecology/Practical studies/Illumination/illuminatiom artif. doc.doc
21. /Module1. General questions of Hygiene and Ecology/Practical studies/Menu apportion ass/Menu-raskl. doc.doc
22. /Module1. General questions of Hygiene and Ecology/Practical studies/Microclimate ass/Air movement. doc.doc
23. /Module1. General questions of Hygiene and Ecology/Practical studies/Microclimate ass/Determination of atmospheric pressure.doc
24. /Module1. General questions of Hygiene and Ecology/Practical studies/Microclimate ass/RESEARCH OF THE FACTOR OF INFRA-RED RADIATION.doc
25. /Module1. General questions of Hygiene and Ecology/Practical studies/Microclimate ass/Topic 06.doc
26. /Module1. General questions of Hygiene and Ecology/Practical studies/Microclimate ass/Topic 07.doc
27. /Module1. General questions of Hygiene and Ecology/Practical studies/Microclimate ass/Topic 11.doc
28. /Module1. General questions of Hygiene and Ecology/Practical studies/Microclimate ass/temperature. doc.doc
29. /Module1. General questions of Hygiene and Ecology/Practical studies/Nois ass/noise and vibration.rtf
30. /Module1. General questions of Hygiene and Ecology/Practical studies/Soil.ass/Topic 18.doc
31. /Module1. General questions of Hygiene and Ecology/Practical studies/Water ass/Mannual 1.doc
32. /Module1. General questions of Hygiene and Ecology/Practical studies/Water ass/Mannual 2.doc
33. /Module1. General questions of Hygiene and Ecology/Practical studies/Work hardness/hardness and intencity 2.rtf
34. /Module1. General questions of Hygiene and Ecology/Practical studies/ultraviolate/manual.rtf
Лекция на тему: Здоровье детей и подростков как гигиеническая проблема. Физиолого-гигиенические
Лекция на тему: «Окружающая среда и здоровье»
Health (who) it is a state of complete physical, mental and social well-being, and not merely the absence of diseases or infirmity
Lecture “ Nutrition as a health factor”
Лекция на тему «Труд и здоровье»
Вода и здоровье” ( лекция для англоязычных студентов 3- го курса ммф ) Лекцию подготовил доцент кафедры гигиены и экологии Клименко А. И
Theme Hygienic assessment of the complex microclimate influence to the human organism
Тopic 8 methods of hygienic assessment of complex effects of the microclimate on the human heat exchange
Theme: methods of hygienic assessment of the dust and chemical admixtures level in atmospheric air
The methods of air sampling
Methods of determination and hygienic assessment of the dust content in the air
Theme: Food poisoning prevention
Theme: the complex assesment of individual health of children and adolescents
Hygienic assessment of conditions and organization of education in comprehensive school
Hygienic estimate of insolation regimen, daylight and candlelight of hospital apartments
Theme: Methods of hygienic investigations and assessment natural illumination and insolating regime in premises Purpose
Solar radiation and its hygienic importance
Topic №4 methods of determination and hygienic assessment of natural lighting in different premises
Topic №5 methods of determination and hygienic assessment of artificial illumination in different premises
Theme: Methods of the hygienic investigation and assessment of the artificial illumination in premises Purpose
The adequacy of the individual nutrition study according to the daily energy intake
Hygienic importance of the air movement in premises
Determination of atmospheric pressure
Research of the factor of infra-red radiation
Тopic №6 Method of determination of temperature and humidity conditions indoors and their hygienic assessment
Method of determination and hygienic assessment of the air movement direction and speed
Methods of determination of со
Microclimate of premises
Theme: Hygienic assessment of the noise and vibration as occupational hazards
Topic №18 method of hygienic assessment of soil according to sanitary examination of the land parcel and results of laboratory analysis of samples
The hygienic estimation of quality of potable water according to inspection and to results of the laboratory analysis
Umanskiy, А. N. Bessmertniy hygienic regulation of water quality. Basic methods of water treatment
Theme: Hygienic assessment of occupational hardness and intensity
Theme: Methods of determination of the ultraviolet radiation intensity as such as preventive dose of it’s irradiation and use it for diseases prevention and air disinfection in premises

Вода и здоровье”

( лекция для англоязычных студентов 3- го курса ММФ )

Лекцию подготовил доцент кафедры гигиены и экологии

Клименко А.И.

Water and health ”


  1. Notion about water and water balance. Physiological, hygienic and epidemiological importance of water. Water as a transmission factor.

  2. Mineral composition of water as a hygienic problem. Diseases and disorder related to mineral composition.

  3. Notion about endogenous diseases, role of biological and geochemical provinces of their origin.

  4. Notion about water quality, most important factors which influence on water quality. Hygienic comparison of water sources.

  5. Organoleptic, chemical, radiological and bacteriological indices of water quality, thei regulation and standardization (stendedai’zeishn) in Ukraine.

  6. General principles of water treatment and prevention diseases related to water quality.


1. Notion about water and water balance. Physiological, hygienic and epidemiological importance of water. Water as a transmission factor.

Water it is the medium where life was born and which is factor of life.

1. 1. Water by the chemical structure is the complex polymer which has

Hydrogenous and hydroxyl radical in its base. Depending conformation structure water may has different chemical and physical properties.

1.2. Physiological importance:

- plastic factor

- medium of chemical reaction and catalyst of chemical reaction

- metabolic factor

- intake medium of drugs and nutrient substances as well as toxic substances

- universal solvent of water soluble substances as such as medium of out put channel of drugs, toxic substances and metabolic excreta ixcrita.

1. 3. Hygienic importance

- hardening factor

- thermoregulation factor

- factor of sport

- factor of purity

1. 4. Epidemic importance

Water is transmission factor for infection diseases origin because water is collector of all pollutions as well as the survival optimum medium for microbes. Untreated water intake is the hazard factor of epidemic process.

Many infectious diseases are transmitted through water e.g. abdominal tyhpus, cholera, disenteria, viral hepatits A, icteric leptospirosis, tularemia, poliomyelitis. Causative agents of infectious diseases can stay alife for a long time being in the water. A part from pathogenic microorganisms water may contain heminth eggs and protozoa’ cysts.

Under conditions of water deficiency other infectious diseases are activating (i.e. the disease which are not transmitted through water). According to WHO data, about 5 millions people die from water deficiency every year; about 500 millions cases of water transmitted infectious diseases are registered every year. The facts mentioned above allow to qualify the problem of water supply as problem N O in the world.


  1. Mineral composition of water as a hygienic problem. Diseases and disorder related to mineral composition.

    1. Inorganic constituents.

-Arsenic ‘a:sinik introduced into water through the dissolution of minerals and ores, from industrial effluents сточные воды , and from atmospheric depositions; concentrations in ground water in some areas are sometimes elevated as a result or erosion from natural sources. The average daily intake of inorganic arsenic in water is estimated to be similar to that from food. Intake from air is negligible незначительный.

-Cadmium e metal is used in the steel industry and in plastics. Cadmium compounds are widely used in batteries. It is released to the environment in waste –water and diffuse pollution is by contamination from fertilizers and local air pollution. Contamination in drinking water may also be caused by impurities in the zinc of galvanized pipes and some metal fittings, although levels in drinking water are usually less than 1 mkg/L. Absorption of cadmium compound is dependent on the solubility of the compound. Cadmium accumulates primarily in the kidneys and has a long and biological half-life in humans of 10-35 years.

-Cyanide saienaid The acute toxicity of cyanide is high. Cyanides can be found in some foods, particularly in some developing countries, and they are usually found in drinking water, primarily as a consequence of industrial contamination. Effects of thyroid sairoid and particularly the nervous system were observed in some populations as a consequence of the long term consumption of inadequately processed cassava kesave маниока containing high level of cyanides.

-Lead is present in tape water to some extent as a result of the dissolution from natural sources, but primarily from household plumbing system containing lead in pipes, solder припой, fittings оборудование or the service connections to homes. The amount of lead dissolved from the plumbing system depends on several factors, including pH, temperature, water hardness, and standing time of the water, with soft, acidic water being the most plumbosolvent. Lead is a general toxicant that accumulates in the skeleton. Infants, children up to six years of age, and pregnant women are most susceptible to its adverse health effects. Lead also interferes intefie with calcium metabolism, both directly and by interfering with vitamin D metabolism. Lead is toxic to both central and peripheral nervous system, inducing subencephalopathic neurological and behavioural effects.

-Mercury is present in inorganic form in surface and ground water at concentration usually less than 0,5 mkg/L. The kidney is the main target organ for inorganic mercury, whereas methylmercury affects mainly the central nervous system.


-Iodine. An adult organism needs 100-200 microgram of iodine per day. The deficiency of iodine causes adenoma of thyroid (endemic goiter). More than 90% of iodine comes into human organism with product of animal or plant origin. Concentrartion of iodine in potable water plays signaling role. Lack of iodine correlates with its lack both in the ground and, therefore, in the products of animal and plant origin in the area.


-Nitrates. Excessive income of nitrates into human organism causes water-nitrate methemoglobinemia (toxic cyanosis). In the human body nitrates are reduced to nitrites. Nitrites cause formation of methemoglobine by binding with hemoglobinum. Methemoglobine cannot transfer oxygen from blood to tissue so tissue hypoxia develops. This disease often occurs in rural regions; usually children (especially babies) are suffering. Infant’s organism is very sensitive to nitrites due to presence of fetal hemoglobin in blood (which is more strongly affected by nitrites) and due to the low activity of methemoglobinreducatse.


-Nitrate and nitrite are naturally occurring ions that are part of the nitrogen cycle. Naturally occurring nitrate level in surface and ground water is below 10 mg/L, When nitrate level in drinking water exceeds 50 mg/L, drinking water will become the main source of total nitrate intake. High level of nitrate in drinking water is hazard for methanoglobinemia origin among bottled - fed infants or less than 3 month of age are most susceptible. They are suckled by artificial milk solved by water containing high concentration of nitrate. This substance are reduced to nitrite in infant intestines which forms methanoglobine. Cyanosis in infant.

-Selenium si’liniem level in drinking water vary greatly in different geographical areas, and are usually much less than the guidline value of 0,01mg/L. Selenium is an essential element for humans and forms an integral part of the enzyme glutathione peroxides. In humans, the toxicity of long-term exposure are manifested in nails, hair and liver.

2.2 Organic constituents

-Polynuclear aromatic hydrocarbons from a variety of combustion kem’baschen and pyrolysis sources have been identified in the environment.

Benzo (a) pyren, which conctitutes a minor fraction of total PAHs have been found to be carcinogenic in mice by the oral route of admini

stration.

-surface active substances and health. A lot of detergents are used

for industrial and private life purpose. Main hygienic properties of them is an ability to penetrate through filters of all diameters being low molecular mass and simple chemical structure. They go to sewage system, water source and drinking water after treatment. They lead to inability to slake by water and have carcinogenic effect.

-The pesticides that are of importance in connection with water quality include chlorinated htdro-carbons and their derivatives, persistent herbicides, soil insecticides, pesticides that are easily leached out выщелащивать from the soil, and pesticides that are systematically added to water supplies for disease vector control.


  1. Notion about endogenous diseases, role of biological and geochemical provinces of their origin.




  1. Notion about water quality, most important factors which influence on water quality.


Sources of water:

    1. Rain

    2. Surface water – impounding reservoir пруды , rivers and streams ручьи, tanks искусственное озеро , ponds маленькое озеро and lakes.

    3. Ground water - Shallow wells грунтовый , Deep wells глубокий колодец,

Shallow wells tap subsoil water from above the first impervious непроницаемый layer in the ground

Deep wells A deep water is one which taps water from the water0bearing stratum below the first impervious layer in the ground. Artesian e’tizien wells are a kind of deep water, because it is held under pressure between two impervious strata.

Springs. When grounded water comes to the surface and flows freely under natural pressure, it’s called a “spring”. Springs may be two types-shallow springs and deep springs. Shallow springs dry up quickly during summer month, whereas deep springs areas do not show seasonal fluctuations in the flow of water.


  1. Organoleptic, chemical, radiological and bacteriological indices of water quality, their regulation and standardization (stendedai’zeishn) in Ukraine.


State Sanitary Regulations and Rules N 383-96 regulate requirements to the quality of potable water and it also spreads on the water supply systems. This document doesn’t regulate the quality of the bottled water and water from water sources if it is used without centralized supply system.

The document establishes the requirement which provide water safety and its good organoleptic features.

There are such hygienic requirements:

  1. Epidemiological safety;

  2. Non-toxicity;

  3. Good organoleptic features;

  4. Radiation safety;


Indices of epidemiological safety.


These indices show the absence of bacteria, viruses and other biological incorporations which are dangerous for human health . Potable water should match microbiological indices listed in the table 1.

Table 1. Microbiological indices of safe potable water








Index

Units

Standards

1.

Microbiological index – number of bacteria in 1 cm³ of water sample


colony forming units/cm³

(CFU/cm³ )

less than 100

2.

Coli-index – number of coli-bacteria in 1 dm³ of water sample


colony forming units/cm³

(CFU/dm³ )

less than 3

3.

Number of thermostable enteric bacilli(feacalis coli-bacteria) in 1 100 cm³ of water sample


colony forming units/ 100 cm³

(CFU/100 cm³ )

none

4.

Number of pathogenic microorganisms in 1 dm³ of water sample


colony forming units/cm³

(CFU/dm³ )

none

5

Number of coli-protobe in 1 dm³ of water sample


patch forming units/ dм3

PFU/dm³

none


Notes:

* - 95% of water samples from water-supply system have to match this requirement.


** - 98% of water samples from water-supply system have to match this requirement. If indices of enteric bacilli is increased additional research (identification of enteric bacilli ) is needed (see table 1 item N3,4,5)


*** - if feacalis coli-forms were found at least in 2 water samples (one after another) than research for pathogenic microorganisms should be started immedately and continued during coming 12 hours.


Indirect bacteriological indices were taken as basic ones (see table 1). They allow to define epidemiological water safety. They are microbic index (general quantity of saprophytic microorganisms) and coli-index (number of enteric bacilli in 1 liter of water).

Observation had revealed following correlation: the less saprophytic bacteria found in the water sample the less possibility to find causative agents of enteric infections.

Enteric bacilli can get in the water with people’s feacalis. That’s why its presence can be sign of other causative agents of enteric infections’ presence in the water. Therefore the significance of colon bacilli’s presence in water as epidemiological index is reasoned by the way enteric bacilli gets in the water. Besides, enteric bacilli is stable than infectious agents of enteric infections. So if the enteric bacilli hadn’t survived in the water, than pathogenic microorganism hadn’t also.

Potable water should match parasitological indices as well. These indices are given in the table 2.

Table 2 Parasitological indices







Index

Units

Standards

1

Number of pathogenic enteric protozoa in 25 dm³ of water


(cells or cysts)/25dm³

none

2

Number of enteric heminth in

25 dm³ of water sample

(cells,cysts,larvas)/25dm³

none


Water chemical content indices.


Excessive concentration of chemical compounds usually take place in the non-treated water as a result of chemical pollution or during water treatment maximum permissible concentration, (MPC). MPC of concentration of certain chemical compounds were established during sanitary-toxicological researches and stated in the State Sanitary Rules and Standards N 363-93 (NB! MPC of chemical compounds which meet in natural water or get in the potable water during water treatment are not stated in the document.

Qualitative characteristic of potable water have to match toxicological indices listed in the table 3.

Table 3. Toxicological indices of water







Index

units

Standards

level of danger

Non-organic compounds

1

Aluminium

mg/dm³

less than 0,2 (0,5)*

2

2

Barium

mg/dm³

less than 0.1

2

3

Arsenic

mg/dm³

less than 0,01

2

4

Selenium

mg/dm³

less than 0.01

2

5

Lead

mg/dm³

less than 0.01

2

6

Nickel

mg/dm³

less than 0.1

3

7

Nitrates

mg/dm³

less than 45,0

3

8

Fluorine

mg/dm³

less than 1,5

3

Organic compoundsb

1

Trihalomethan (sum)

mg/dm³

less than 0,1

2




Chloroform

mg/dm³

less than 0,06

2




Dibromchlormethanum

mg/dm³

less than 0,01

2




Carbon tetrachloride

mg/dm³

less than 0,002

2

2

Pesticides

mg/dm³

less than 0,0001




Integral indices

1

Oxidability (КмnО4)

mg/dm³

less than 4,0




2

General organic carbon

mg/dm³

less than 3,0





Notes:

* - Figures in the brackets are permissible if aluminiun containing reagents were used during water treatment;

** - list of controlled pesticides is established according to current situation.

Potable water should not contain other toxic compounds (e.g. cadmium, nitrites, cyanide, chromium, 1,1-dichloroethylen, 0,2-dichlorethane, benzapilene)


Concentration of residual quantities of disinfectants after disinfection have to match following requirements:

  1. when water is treated with chlorine, the concentration of free residual

chlorine should be not less than 0,3-0,5 mg/dm³ ( if time of exposure is less than 30mins) and concentration of combined residual chlorine should not exceed 0,8-1,2 mg/dm³ (if time of exposure was more than 60 mins). If there is both compound and free chlorine, only one of them may be controlled (if the concentration of residual free chlorine is less than 0,3 mg/dm³ only the compound chlorine is controlled).

  1. when water is treated with ozone, the concentration of ozone have to be

0,1-0,3 mg/dm³ and duration of contact of water and ozone shouldn’t be less than 4 min.


If other disinfectants and coagulants(which are allowed for use by Ministry of Health of Ukraine) are used for water treatment, then their concentration should not exceed the standards.


Organoleptic features of water.(see table 4)


Organoleptic features of potable water are regulated by 2 groups of indices:

  1. those which exclude adverse visual and reflex reaction of person (taste, smell, turbidity, color);

  2. those which regulate concentration on certain chemicals which can influence organoleptic features of water. The chemicals are sulfates (the increase if sulfate in the water gives to the bitter taste of the water), chlorides (the increase of chlorides in the water gives salty taste of water), iron (the increase of iron in the water gives turbidity, yellow opalescence, if the level of iron is more then 1 mg/dm³ the water acquire metallic taste).


Table 4. Organoleptic indices of water quality.




Index

Units

Standards

Level of danger

1

Smell

index of dilution

2




2

Turbidity

НЕМ

0,5 (1,5)




3

Color

degree

20 (35)




4

Taste

index of dilution

2




5

рН

units

6,5-8,5




6

General mineralization

mg/dm³

1000 (1500)




7

General hardness

mg-equ/dm³

7 (10)




8

Sulfates

mg/dm³

250 (500)

4

9

Chlorides

mg/dm³

250 (350)

4

10

Cuprum

mg/dm³

1,0

3

11

Manganese

mg/dm³

0,1

3

12

Iron

mg/dm³

0.3

3

13

Chlorophenol

mg/dm³

0.0003

4


Notes:

* - index of dilution (the water is diluted till the smell and taste dissapears);

** - nephelometric units

*** - figures in the brackets are assumed in concrete situation.


Water should not contain any other components which can change its organoleptic features.


Indices of radiation water safety.

Indices of radiation water safety are determined by maximum permissible level of total α-radiation and β-radiation activity. In case of exceeding levels of radiation listed in the table 5 other researches have to be done.

Table 5. Indices of radioactive safety of water







Index

Units

Standards

1

Generaral dioactivity concentration of α-radiation


Bq/dm³

less than 0,1

2

Generaral dioactivity concentration of β-radiation

Bq/dm³

less than 1,0


Notes: Standards of potable water radiation is regulated and co-ordinated by Principle State Sanitary Inspector of Ukraine.


Indices of physiological full-value of water.


Physiological full-value of potable water is determined by correlation between its mineral content and biological needs of human. It is based on the advisability of certain elements which are maximum permissible or minimal required for normal functioning of human body e.g. excessive mineralization may cause urolythiasis and worsen washing process; general mineralization less than 100mg/dm³ may cause increase in heart morbidity.

Table 6. Indices of physiological full-value of mineral content of potable water







Index

Units

Recommended value

1

General mineralization

mg/dm³

not less than 100,0

less than 1000,0

2

General hardness

mg-equ/dm³

not less than 1,5

less than 7,0

3

General alkalinity

mg-equ/dm³

not less than 0,5

less than 6,5

4

Magnesium

mg/dm³

not less than 10,0

less than 80,0

5

Fluorine

mg/dm³

not less than 0,7

less than 1,5


The quality of water sources greatly defines water qualitative characteristics.

Because of this strict correlation all-Union Standards N2761-84 “Water sources for centralized water-supply systems. Hygienic requirements and rules for choosing the water source” were worked out. According to the document surface and underground water-sources are divided into 3 types by the type of needed water treatment.

Classification of underground water-sources:

1st type – water doesn’t require any treatment and can be used safely;

2nd type – there are some impairments of water quality but water can be brought to standards by aeration, filtration and disinfection;

3rd type – additional or even specific treatment have to be performed for safe usage;


Classification of surface water sources:

1st type – disinfection and filtration with or without coagulation have to be performed for safe usage;

2nd type – coagulation, sedimentation, filtration and microfiltration (if there is plankton in it) and disinfection have to be performed before usage;

3rd type – to bring this water to standards all methods required for the 2nd type plus additional specific methods (e.g. clarification, decoloration ,etc) have to be used.


Table 7. Indices of water-sources quality (all-Union Standards N 2761-84)


Indices

Units

Standards by types of water-sources

1

2

3
Underground water-sources

Turbidity, less than

mg/dm³

1,5

1,5

10,0

Color, less than

degree

20

20

50

Hydrogen index

рН

6-9

6-9

6-9

Iron (Fe), less than

mg/dm³

0,3

10

20

Marganese (Mn), less than

mg/dm³

0,1

1

2

Sulphuretted hydrogen (H2S), less than

mg/dm³

none

3

10

Fluorine (F), less than

mg/dm³

0,7-1,5

0.7-1,5

5

Oxidability

mg O/dm³

2

5

15

Coli-index




3

100

1000
Поверхностные источники водоснабжения

Turbidity, less than

mg/dm³

20

1500

10000

Color, less than

degree

35

120

200

Smell if the temperature is 20º and 60о, less than

points

2

3

4

Hydrogen index

рН

6,5-8,5

6,5-8,5

6,5-8,5

Iron (Fe), less than

mg/dm³

1

3

5

Marganese (Mn), less than

mg/dm³

0,1

1

2

Phytoplanktone:filmy and filament, less than


Unicellular less than


mg/dm³


1


1000


5


100000


50


100000

Oxidability

mg O/dm³

7

15

20

БПК полное, less than

mg O/dm³

3

5

7

Number of lactose-positive enteric bacilli, less than




1000

10000

50000


All-Union State Standard N 2761-84 suggest to choose water sources in the following order according to their sanitary safety: middle pressure water, middle non-pressure water, subsoil water, surface water. Power of water-supply pipe shouldn’t exceed permissible outcome of water from the water source irrespectively of the season. The choice of a water source is permissible if organization of sanitary security around it is possible. Sanitary guarding regime around the chosen place is also required.

Decentralized water-supply have to match regulations stated in the State Sanitary Rules and Standars N 1226-75 “Sanitary rules for building and keeping wells, captation of springs used for decentralized water-supply”. According to the document, water from water sources mentioned above have to match following parameters:

  1. transparency (not less than 30 cm by script);

  2. colorless (less than 30˚);

  3. free from smell and taste (less than 3 points if t˚C is 20˚C);

  4. less than 10 mg/l of nitrates;

  5. coli-index have to be less than 10, coli-titre – not less than 100.


New State Sanitary Regulations and Standards were elaborated in Ukraine. The following requirement to water quality under conditions of non-centralized water-supply are foreseen:

1. physical-chemical requirements:

  1. transparency (turbidity have to be less than 2 mg/dm³);

  2. colorless (less than 20º)

  3. dry residual (less than 1500 mg/dm³);

  4. concentration of ammonia – less than 2,2 mg/dm³;

  5. concentration of nitrites - less than 3,3mg/dm³;

  6. concentration of nitrates – less than 45mg/dm³;

  7. general hardness – less than 10 mg-equ/dm³;

  8. concentration of chlorides – less than 350 mg/dm³;

  9. concentration of sulfates – less than 500mg/dm³;

  10. concentration of fluorine – less than1,5 mg/dm³;

  11. oxidability (KMnO₄) - less than5 mgO/dm³;

  12. water should be without any signs of of organic pollution (e.g. with feacalis). Indirect indices of organic pollution is increase of chlorides, ammonium, nitrates and oxidability of water comparing with previous researches.

  13. Water should not contain any toxic elements or chemical compounds not listed above. Otherwise it is counted as sign of chemical pollution.

2. Sanitary – bacteriological requirements:

  1. microbic number – less than 100/cm³;

  2. coli-index – less than 10;

  3. coli-protobes in 1 dm³ of water sample – absent;

  4. other pathogenic and conditionally-pathogenic microorganisms, viruses, protozoa, hemonths’ eggs have to be absent.


Methods of water treatment.


Surface (rarely underground ) water-sources are usually polluted. Therefore the water doesn’t match standards and so have to be treated before usage. Most often water from surface reservoir doesn’t correspond with standards by transparency, color and content of microorganisms.


  1. General principles of water treatment and prevention diseases related to water quality.

The purpose of water treatment is to produce water that is safe and wholesome ‘heulsem The method of treatment to be employed depends upon the nature of raw water, and the desired standards of water quality. The components of a typical water purification system comprise one more of the following measure:

    1. Storage.

    2. Filtration.

    3. Disinfection.

- Storage is natural purification and we may look at it from three point of view

1. Physical: by mere всего лишь storage, about 90% of the suspended impurities загрязнений settled down in 24 ours by gravity (e) .

2. Chemical: the aerobic bacteria oxidize the organic matter present in the water with the aid of dissolved oxygen, As a result, the content of free ammonia is reduced and rise in nitrates occurs.

3. Biological: The pathogenic organisms gradually die out till 90% in the first 5-7 days. This is one of the greatest benefit of storage. The optimum period of storage of river water is considered to be about 10-14 days.

In case use special chemicals the mass of suspended impurities may enlarge and speed of sedimentation during storage increase.


There are two groups of water treatment methods (see table 8): those which are always applied before giving water fro use (basic methods) and those which are applied only in certain conditions (specific methods).


Table 8 Classification of water treatment methods


Basic methods

Specific methods

Methods of clarification and decoloration

Methods of disinfection

Coagulation

Sedimentation

Filtration

Methods which require chemical agents’ usage

Chlorination

Ozonization

Silvering

Methods which do not require chemical agents’ usage

Ultraviolet

Boiling

-radiation

ultrasound

deodorization

deferrization

desalination

softening

fluorination

defluorination

decontamination

degassing


1. Basic methods.

1) Coagulation.

The main point of the method is to perform a coagulation by usage coagulants so most of the suspension particles will be coagulated. Coagulants are chemical compounds which have electric charge opposite to electric charge of suspension particles and are able to coagulate. Al(SO₄)₃, FeSo₄, FeCl₃ are usually used as coagulants. If these substances (coagulants) are put in the water the electrical charge of colloid particles is neutralized, then they combine and form large flakes which precipitate. Flakes adsorb colloid and small suspension particles and during precipitation flakes mechanically adsorb other suspension particles. During coagulation quick clarification and decoloration of water take place. At the same time a part of microorganisms excludes.


2). Sedimentation.

Sedimentation is done right after coagulation in order large particles to gravitate. Speed of particles sedimentation depends on dimension of particles and on water temperature(see table 9)

Table 9. Correlation between sedimentation speed and particles’ dimensions


Diameter of a perticle, mm

Name of the particle

Time of particles’ sedimentation on the 1m depth

1

Gravel

10 sec

0,1

Fine sand

2 min

0,01

sludge

2 hours

0,001

argilla

7 days

0,0001

loam

2 years


Sedimentation tank is a reservoir where water from thin channel comes straightly into a large reservoire and water flow becomes slower. As a result, suspension particles gravitate on the bottom of the reservoir. The correlation between speed of particles gravitation and its dimension is given in the table 9.

Depending on the direction of water flow, sedimentation tanks are divided into horizontal (common and radial) and vertical types.


Fig. 2. Layout of horizontal and vertical sedimentation tanks




3) Water filtration.

Water filtration helps to exclude those particles which were not excluded during first and second stages of water treatment as only large particles can be eliminated during coagulation and sedimentation. During filtration water is partially released from microorganisms as well.

Water is filtrated by passing through porous material which keeps suspension particles. Gravel without admixtures is usually used as filtrating material(see fig. 3)


Fig. 3. The layout of sandy-gravel filter.





а) – layer of water; б) – sand; в) – gravel; г) – drainage


Filtration is held in the specific constructions – filters. There are two types of filters: slow and quick.

Filtration becomes more difficult if eliminatation of plankton (small animals and plants) was not performed before. Plankton is usually excluded with microfilters.

4) Water disinfection.

Methods mentioned above do not release water from microorganisms fully. Disinfection is needed in order the water to match all microbiological indices.

The most common method of water disinfection is chlorination. Gaseous chlorine and its compounds (chlorinated lime, hypochlorites, chloraminum, chlorine oxide) are used. Chlorine is a gas with a specific smell which irritates mucous. It is attributed to poisoning chemicals. That’s why chlorine is used only in huge filtrating stations and is kept in steel tanks. Chlorinated lime is more often used in small filtrating stations under conditions of local water supply.

Disinfectioning effect of chlorine lies in the direct influence of chlorine as strong oxidative agent on the proteins. It cause denaturation of microbic cell cytoplasma and inactivation of cell’s enzymes (esp dehydrogenase).

Chlorinated lime is a product of chlorine and slaked lime interaction. It is white soluble powder. Chlorinated lime generates HOCl‾ over a water and thus conditions bactericidal effect. Fresh chlorinated lime contain about 36% of active chlorine and it’s not stable. Under influence of water, CO, warmness or light it turns into calcium chloride.

Chosen dose of chlorine must guarantee water disinfection during water chlorination. Dose of chlorine is composed of chlorine absorptivity and residual chlorine. Chlorine absorptivity is quantity of chlorine (mg) which consumed for oxidation of organic and easily-oxidable non-organic compounds. In order to receive bactericidal effect of chlorine the quantity of introduced in the water chlorine should cover chlorine absorptivity and make a certain quantity of chorine residual. Effectiveness of chlorination is judged by chlorine residual.

Water acquire specific smell and taste if content of chlorine exceed 0,5mg/l. That’s why disinfection dose of chlorine should be such that the chlorine residual wouldn’t exceed 0,3-0,5mg/dm³ after further water treatment. Thus the dose of chlorine is considered to be sufficient if 0,3-0,5 mg/dm³ of residual chlorine stays in the water after 30 minutes of chlorination and 0,8-1,2 mg/dm³ of combined chlorine after 60 minutes of disinfection.

Chlorination is quite safe for people’s health. Experiments proved that chlorine absorbes in the oral cavity. In case water contain considerable quantities of chlorine, a small part of it gets to the stomach and reacting with stomach content chlorine neutralizes. It is proved that up to 2,5 mg/dm³ of chlorine in water doesn’t cause any pathological processes in the human organism.

The following typs of water chlorination are differed: ordinary, double, superchlorination and chlorination with preammonization.

Ordinary chlorination. It is carried out once right after clarification and decoloration. The dose guarantee the concentration of residual chlorine from 0,3 till 0,5 mg/dm³.

Double chlorination. It is used in case of considerable bacterial pollution and for the purpose of preventing plankton growth on the filters. The general consumption of chlorine is not increased. The main dose is introduced before coagulation and small dose is introduced after filtration. So the concentration of residual chlorine is 0,3-0,5 mg/dm³.

Superchlorination (hyperchlorination). It is used in case of considerable bacterial pollution and field conditions when 30-minutes-contact of chlorine with water is not possible. Water is treated with big doses (10-20 mg/dm³ and more). Chlorine redundancy is taken away by aeration and by chemical methods (thiosulfate, sulfur dioxide binding, filtrating through absorbed carbon). Elimination of chlorine redunbancy is called dechlorination.

Chlorination with preammonization. The main point of the method is to introduce ammonium in water first and in a couple of seconds – chlorine. Thus chloraminum is generated in the water. Comparing with chlorine chloraminum is more stable and has longer bactericidal effect. It also doesn’t generate chlorphenols and thus doesn’t give annoying smell to water which contain phenol. But as chloraminum has less oxidability so the quantity of introduced substance and time of exposure should be increased.


2. Specific methods of water treatment.

In case if basic methods didn’t give the desired result, specific methods of water treatment are used. Their classification is given in the table 8.

Deodorization – removal of annoying smell. It is achieved by aeration, oxidizer treatment, filtration through absorbed carbon.

Deferrization – removal of excessive quantity of iron. It is carried out in the specific constructions - cooling stacks (water is splashed there). Here Fe⁺² is reduced to Fe⁺³and detains in the sedimentation tanks and filters.

Softening – removal of salts which condition water hardness. The most old method is calc-alkali method. Modern methods are based on the usage of ion-exchange pitch. There are natural and artificial ionits. Usage of cationic pitches helps to remove cations, usage of anionic pitches helps to remove anions.

Desalination – removes excess of salts. There are a lot of methods of desalination: distillation, chemical methods (with reagents’ usage, inoexchange), usage of semipermeable membranes (hyperfiltration) and electrodialysis.

Decontamination- removes radioactive isotopes. Though coagulation, sedimentation and filtration reduce the content of radioactive substances for 70-80%, other methods for better decontamination are also used.

Defluorination – water is filtrated through activated aluminium hydroxide if concentration of fluorine exceed 1,5 mg/dm³. Sometimes, concentration of fluorine is decreased by dilution with free from fluorine water.

Flurination – is carried out if concentration of fluorine in water is low. The purpose of fluorination is caries prophylaxis. Fluoride is usually used for fluorination.

Degassing – removal of different toxic compounds, including was gases. There are a lot of different types of the methods (sorption, ion-exchange, with chemical reagents usage, etc.) Choice of degassing method depends on the toxic compound.

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