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Total microbial count for drinking water. Sanitary and microbiological control over the waters of open reservoirs, drinking water quality

Raw milk - milk that has not been subjected to heat treatment at a temperature of more than 40 ° C or treatment, as a result of which its constituent parts are changed.

Raw milk may contain dangerous microorganisms that can cause infectious diseases and food poisoning. Raw milk ranks first among the products, the use of which is associated with the risk of getting a serious illness.

The type of milk depends on the amount of MAFAnM in 1 ml of milk, according to sanitary rules and regulations (SanPiN 2.3.2.1078-01), raw milk is divided into:

for raw milk, the highest grade - no more than 300 thousand bacteria in 1 ml;
for raw milk, I grade - no more than 500 thousand bacteria in 1 ml;
for raw milk, II grade - no more than 4 million bacteria in 1 ml.

The purpose of the study: to study the level of microorganisms in raw milk. In this regard, the task was set: to determine the level of the total microbial number in milk, namely QMAFAnM (the number of mesophilic aerobic and facultative anaerobic microorganisms).

The material for the study was raw milk taken from a cow named "Snezhinka", a Simmental breed located in the hospital of the Bashkir State Agrarian University.

Picture1 . A sample of the tested milk.

The determination of QMAFAnM was carried out in accordance with the current GOST R 53430-2009. The method is based on the ability of mesophilic aerobic and facultative anaerobic microorganisms to multiply on a nutrient medium (MPA) at a temperature of 30±1°C for 72 hours.

I prepared successive tenfold dilutions from raw milk, i.e. 1 ml of raw milk was added to a test tube with 9 ml of sterile water to obtain the first dilution 1:10 (10‾¹). From the first dilution, 1 ml was transferred to the second test tube with 9 ml of sterile water - the second dilution was obtained 1:100 (10‾²) and so on until a dilution of 10 -5.

Isolation QMAFAnM from samples of raw milk was carried out by seeding the last three dilutions (10 -3, 10 -4, 10 -5) (table 1).

Table1 .

Scheme of crops on nutrient media

Nutrient medium	Released microorganisms	Breeding
Nutrient medium	Released microorganisms

1 ml of each dilution was added to one Petri dish, with a pre-marked lid, and filled with 14±1 ml of agar melted and cooled to a temperature of 40-45°C. Immediately after pouring the agar, the contents of the Petri dish were thoroughly mixed by slight rotational rocking to evenly distribute the inoculum. After the agar solidified, the Petri dishes were turned upside down and placed in a thermostat at 30±1°C for 72 hours.

The number of grown colonies was counted in each cup, multiplied by the degree (formula 1).

Calculation formula: Х= n*10 m

where n is the number of colonies counted on a Petri dish;

m is the number of tenfold dilutions.

Received the following average value (table 2).

Table 2.

Number of grown colonies

Table 2 shows that 21 colonies grew in a Petri dish with a dilution of 10‾ 3, which corresponds to 21,000 microorganisms; in a dish with a dilution of 10‾ 4 - 13 colonies (130,000), and in a dish with a dilution of 10‾ 5 - 6 colonies (600,000). The average value of the three indicators was 250333 (250.333 thousand) microorganisms.

Thus, the total microbial number in milk, namely the number of mesophilic aerobic and facultative anaerobic microorganisms in the milk under study is 250.333 thousand. According to sanitary rules and regulations (SanPin 2.3.2.1078-01), this raw milk can be classified as "highest grade" , since QMAFAnM amounted to less than 300 thousand bacteria in 1 ml.

It should also be noted that this raw milk complies with GOST R 53430-2009, is suitable for direct consumption, processing into dairy products, meets the requirements of the sanitary condition of animals and the hygiene of milk production.

Bibliography:

Gosmanov R.G. Sanitary microbiology: Textbook. - St. Petersburg: Publishing house "Lan", 2010. - 240 p.
Ilyasova Z. Z. Guidelines for practical exercises S2.B.11 Veterinary microbiology and mycology: Guidelines / Z. Z. Ilyasova. - Ufa: Bashkir State Agrarian University, 2015. - 28 p.
Milk and milk processing products. Methods of microbiological analysis: GOST R 53430-2009. – Approved and put into effect by the Order of the Federal Agency for Technical Regulation and Metrology dated November 27, 2009 No. 520-st. - M. : Standartinform, 2010.

With this method of water analysis, a certain amount of water is passed through a special membrane with a pore size of about 0.45 microns. As a result, all bacteria present in the water remain on the membrane surface. After that, the membrane with bacteria is placed for a certain time in a special nutrient medium at a temperature of 30-37 °C. During this period, called the incubation period, the bacteria have the opportunity to multiply and form well-defined colonies that are already easy to count. As a result, you can observe this: Or even this picture:

Since this method of water analysis involves only determining the total number of colony-forming bacteria of different types, its results cannot unambiguously judge the presence of pathogenic microbes in the water. However, a high microbial count indicates a general bacteriological contamination of water and a high probability of the presence of pathogenic organisms.

When analyzing water, it is necessary to control not only the content of toxic chemicals, but also the number of microorganisms that characterize the bacteriological contamination of drinking water. TMF is the total microbial number. In the water of centralized water supply, this number should not exceed 50 CFU / ml, and in wells, wells - no more 100 cfu/ml

Sanitary and microbiological research of water is carried out in a planned
order for the purpose of current surveillance, as well as for special epidemiological
kim testimony. The main objects of such research are:

- drinking water of the central water supply (tap water);

- drinking water of non-centralized water supply;

— water from surface and underground water sources;

- wastewater;

- water of coastal zones of the seas;

- Swimming pool water.

The main indicators for assessing the microbiological state of drinking water in accordance with the current regulatory documents are:

1. Total microbial count (TMC) - the number of mesophilic bacteria in 1 ml of water.

If the titer- the smallest volume of water (in ml) in which at least one living
microbial cell related to BGKP.
BGKP index- the amount of BGKP in 1 liter of water.

3. The number of spores of sulfite-reducing clostridia in 20 ml of water.

4. Number of coliphages in 100 ml of water.

Determination of TMC makes it possible to assess the level of microbiological contamination of drinking water. This indicator is indispensable for the urgent detection of massive microbial contamination.

Total microbial count- this is the number of mesophilic aerobic and facultative anaerobic microorganisms capable of forming colonies on nutrient agar at a temperature of 37 ° C and within 24 hours, visible at a twofold increase.

When determining the total microbial number, 1 ml of the test water is added to a sterile Petri dish and 10-12 ml of warm (44 ° C) molten nutrient agar is poured. The medium is gently mixed with water, uniformly and
without air bubbles distributing along the bottom of the cup, then cover with a lid and leave to solidify. Crops are incubated in a thermostat at 37 °C for 24 hours. Count the total number of colonies grown in both dishes and determine the average value. The final result is expressed as the number of colony forming units (CFU) in 1 ml of the test water. 1 ml of drinking water should contain no more than 50 CFU

Definition of BGKP
At the same time, common coliform bacteria - OKB and thermotolerant coliform bacteria - TKB are determined.

GKB are gram-negative, non-spore-forming rods that ferment lactose to acid and gas at 37°C for 24-48 hours. TKB are among the OKB, they have their signs, but I ferment at 44 ° C. For the determination of enterobacteria - the method of membrane filters or titration.

Microbial number - the main criteria for assessing the microbiological state of drinking water, based on the current regulatory documents, is TMC (total microbial number), which characterizes the number of aerobic and anaerobic bacteria in one milliliter of water, formed per day at a temperature of 37 degrees, in a nutrient medium.

Quality indicators of drinking water of water supply systems.

This indicator is virtually indispensable for the rapid detection of massive microbial contamination.

For determination of the total microbial number one milliliter of the test water is added to a sterile Petri dish, then 10-15 ml of warm (about 44 ° C) nutrient agar is poured in a molten form. The medium is carefully mixed with water, distributed evenly and without air bubbles over the bottom of the dish, then closed with a lid and left in the Petri dish until solidified. The same is done in the other cup. Sowing in a thermostat is incubated at a temperature of 37 ° C during the day. Then, at double magnification under a microscope, the total number of colonies grown in two cups is counted, and the average value is determined. In 1 ml of drinking water should not be more than 50 CFU.

(main method)

The method is based on filtering a certain volume of water (300 ml) through membrane filters, growing crops on a differential diagnostic medium with lactose (Endo) and subsequent identification of colonies by cultural and biochemical characteristics.

Membrane filters prepared for analysis (boiled or sterilized in another way) are placed with sterile tweezers into the funnel of the filter apparatus. A measured volume of water is poured into the funnel of the device and a vacuum is created. After filtration, the filter is removed and placed on the surface of the Endo nutrient medium without turning over.

One cup can fit 3 filters. In the study of drinking water, 3 volumes of 100 ml are filtered. when analyzing water of unknown quality, it is advisable to filter other volumes of water to obtain isolated colonies on the filter (10.40, 100 and 150 ml).

The filter dishes are incubated upside down in an incubator at t 37°C for 24 hours.

If there is no growth on the filters or atypical membranous, moldy, blurry colonies have grown, they give a negative result. OKB and TKB are absent in 100 ml of the studied water.

With the growth of typical isolated lactose-positive (dark red with prints on the reverse side of the filter) colonies on the filters, their number is counted and they begin to confirm their belonging to the OKB and TKB.

Microscopic examination of smears from 3-4 Gram-stained colonies is carried out (gram-negative ones are taken into account);

The presence of oxidase is determined (oxidase-negative ones are taken into account, since oxidase-positive gram-negative rods do not belong to enterobacteria, but can be, for example, pseudomonads);

The fermentation of lactose to acid and gas is determined at a temperature of 37 ° C, which is important for slightly colored colonies and their relationship to TKB, and at a temperature of 44 ± 0.5 ° C, in order to decide whether they belong to TKB.

Setting up an oxidase test

On paper moistened with 1% alcohol solution of α-naphthol and 1% aqueous solution of dimethylphenylenediamine, a part of the colored colony is applied with a platinum loop or a glass rod. the reaction is considered positive if within 1 minute, a maximum of 4 minutes, a blue or purple color appears. Oxidase-positive colonies are not taken into account and are not subjected to further research.

It is possible to transfer the filter with colonies to the paper moistened with the reagent. You can use ready-made paper systems (NIBs) moistened with distilled water.

Part of the colonies of gram-negative oxidase-negative bacteria are tested for the ability to ferment lactose. This uses a semi-liquid medium with lactose and a pH indicator. Sowing is done by injection to the bottom in 2 test tubes. One is incubated at a temperature of 37 ± 1 ° C for 24-48 hours to confirm the relationship to TKB, the other at a temperature of 44 ± 0.5 ° C for 24 hours, registration is possible after 4-6 hours to confirm the presence of TKB.

When superimposing colonies on the filter, they are sieved, then the resulting isolated colonies are identified. Colonies are counted as OKB - if they are red on Endo, they contain gram-negative oxidase-negative rods that decompose lactose at a temperature of 37 ° C to acid and gas. Colonies are counted as TKB if they contain gram-negative oxidase-negative rods that ferment lactose at a temperature of 44 °C to acid and gas (Scheme No. 2).

SCHEME № 2

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Total microbial count

- drinking water of the central water supply (tap water);

- drinking water of non-centralized water supply;

— water from surface and underground water sources;

- wastewater;

- water of coastal zones of the seas;

- Swimming pool water.

The main indicators for assessing the microbiological state of drinking water in accordance with the current regulatory documents are:

1. Total microbial count (TMC) - the number of mesophilic bacteria in 1 ml of water.

If the titer- the smallest volume of water (in ml) in which at least one living
microbial cell related to BGKP.
BGKP index- the amount of BGKP in 1 liter of water.

3. The number of spores of sulfite-reducing clostridia in 20 ml of water.

4. Number of coliphages in 100 ml of water.

Definition of BGKP
At the same time, common coliform bacteria - OKB and thermotolerant coliform bacteria - TKB are determined.

Principles of drinking water rationing

The same is done in the other cup. Sowing in a thermostat is incubated at a temperature of 37 ° C during the day. Then, at double magnification under a microscope, the total number of colonies grown in two cups is counted, and the average value is determined. In 1 ml of drinking water should not be more than 50 CFU.

The mismatch of water, as well as chemical, makes it undrinkable. If your water source is not protected from direct environmental exposure or the utility systems are outdated or have not been cleaned for a long time, then microbiological testing is a must. Your health and safety depends on it! This is especially important for those who use the well. - ground, it directly contacts the soil, which means it threatens to “drink” you with nitrates, heavy metals, ammonia, and, of course, harmful organic substances that enter the soil as a result of the activities of agricultural farms or lands.

Table 1 shows the microbiological indicators of the current standard SanPiN 2.1.4.1074-01 for drinking water:

Table 1. Microbiological standards for drinking water

Standard microbiological analysis

The standard microbiological analysis of drinking water at Moscow State University includes the determination of three indicators: the total microbial number, the number of total coliform and thermotolerant coliform bacteria.

Advanced microbiological analysis

An extended microbiological analysis of water includes the analysis of five indicators: total microbial count, total coliform bacteria count, thermotolerant coliform bacteria count, coliphage titer and content of spores of sulfite-reducing bacteria.

Microbiological analysis of surface water bodies (ponds, rivers, pools)

Often there are bodies of water on our sites or nearby, where we and our children like to spend time with pleasure. Of course, the water in these reservoirs is not potable, but its safety for humans, as well as drinking, is regulated. Table 2 presents the microbiological indicators of the current standard for hygienic requirements for the protection of surface waters (SanPiN 2.1.5.980-00)

Table 2. Microbiological standards for recreational water use, as well as within the boundaries of populated areas

Standard microbiological analysis (surface waters)

Microbiological analysis of water not intended for drinking includes the determination of the number of two indicators: total coliform and coliform thermotolerant bacteria.

Advanced microbiological analysis (surface waters):

In addition to the two main indicators, we propose to conduct an additional analysis for the content of: coliphages, opportunistic yeasts and micromycetes (frequent satellites of opportunistic diseases) and the self-purification index of the reservoir.

Determination of bacteria of the genus Salmonella and the genus Enterococcus

With a significant excess of SanPiN 2.1.5.980-00 standards, as well as possible fecal contamination of the reservoir, we propose to analyze for the presence of pathogens of intestinal infections (genus Salmonella and Enterococcus).

Glossary

Total Microbial Abundance (TMC)

The method determines in drinking water the total number of mesophilic aerobic and facultative anaerobic microorganisms (FMC) capable of forming colonies on nutrient agar at a temperature of 37 ° C for 24 hours, visible with a 2-fold increase. This indicator identifies potential bacteria that can harm human health.

Common coliform bacteria (TCB)

Common coliform bacteria (CBC) are gram-negative, oxidase-negative, non-spore-forming rods that can grow on differential lactose media, ferment lactose to acid, aldehyde and gas at a temperature of (37 + 1) ° C for (24-48) hours. Many representatives of this group are microorganisms of the normal microflora of the stomach, so the excess of this group of microorganisms may indicate possible anthropogenic (including fecal) water pollution.

Thermotolerant coliform bacteria (TCB)

Thermotolerant coliform bacteria (TCB) are among the common coliform bacteria, have all their characteristics and, in addition, are able to ferment lactose to acid, aldehyde and gas at a temperature of (44 ± 0.5) ° C for 24 hours. As well as OKB, they are an indicator group, however, they are more stable in the environment: that is why the detection of this group of microorganisms in water can indicate unequivocal contamination of it with human waste products.

coliphages

Coliphages, determined by the standard method (MUK 4.2.1018-01), are E. coli viruses (Escherichia coli) and are considered by epidemiologists as an additional, and sometimes more sensitive, method in determining water pollution by microorganisms of the E. coli group. Virus particles, and coliphages in particular, are more resistant to the environment than their host bacteria. In this regard, the presence of coliphages can serve as a reliable marker of older faecal contamination of the water source. A direct correlation was shown between the content of coliphages in water and enteroviruses dangerous to humans, so the presence of coliphages in water may indicate a viral infection of the source. The current regulatory document (SanPiN 2.1.4.1074-01) implies the absence of coliphages in 100 ml of water.

Spores of sulfite-reducing clostridia

Sulphite-reducing clostridia are spore-forming anaerobic rod-shaped microorganisms, which are an additional microbiological indicator of fecal pollution of a reservoir. Unlike relatively unstable coliform and thermotolerant coliform bacteria, Clostridium spores can persist in water bodies for a long time. Clostridia are found in the intestines of humans and domestic animals, however, if ingested with water in large quantities, they can cause food poisoning. The sulfite-reducing clostridia include clostridia dangerous to humans (Clostridium botulinum, Clostridium perfringens, Clostridium tetani), which cause severe diseases. According to the current standard (SanPiN 2.1.4.1074-01), Clostridia spores should be absent in 20 ml of water.

Opportunistic yeasts and micromycetes

Conditionally pathogenic yeasts and micromycetes (molds) include a large heterogeneous group of fungal organisms that can grow saprotrophically at 37 °C. It includes representatives such as Candida albicans and Cryptococcus neoformans, which are a frequent factor in human opportunistic diseases, causing candidiasis (fungal skin diseases), thrush, and so on. Other micromycete organisms (Cladosporium cladosporioides, Aspergillusniger) can be active sensitizers of allergic reactions, and sometimes allergens themselves. In the Russian Federation, water is not standardized for molds and yeast organisms in water.

Determination of the self-cleaning index (from MUK 4.2.1884-04)

The total number of microorganisms is not standardized in the water of reservoirs in recreation areas, since the level of this group of microorganisms largely depends on the natural characteristics of each object, season, etc.

However, when choosing a new source of water supply or a place of recreation in the water of reservoirs, it is additionally necessary to determine the total microbial population, which grows:

at a temperature of 37 ° C for 24 hours;
at 22°C for 72 hours.

It is assumed that:

TMP at 37 °C is mostly represented by alochthonous microflora (introduced into the reservoir as a result of anthropogenic pollution, including fecal pollution);
TMP at 20-22 °C is represented, in addition to the alochthonous, aboriginal microflora (natural, characteristic of this reservoir).

The ratio of the numbers of these groups of microorganisms makes it possible to judge the intensity of the self-purification process. At the end of the self-cleaning process, the OMC coefficient is 22 ° C / OMC 37 ° C. In places of pollution by household sewage, the numerical values of both groups are close.

The indicator provides additional information on the sanitary state of water bodies, sources of pollution, and self-purification processes.

Tap water is inoculated in a volume of 1 cm3 (1 ml). The sample is introduced into a sterile Petri dish, poured into 10-12 ml of molten and cooled to 45°C nutrient agar, mixed with water. The inoculation is incubated at 37°C for 1-2 days. Then the number of colonies grown on the surface and in the depth of the medium is counted and calculated microbial count of water- the number of microorganisms in 1 ml.

Titration method
To study tap water, crops are made in three volumes of 100 ml, three volumes of 10 ml and three volumes of 1 ml in a glucose peptone medium. Crops are incubated for a day at 37°C. Fermentation is judged by the presence of gas bubbles in the float. Fermented or cloudy samples are cultured on Endo medium.
From the grown colonies, smears are made, stained according to Gram and an oxidase test is performed, which allows to differentiate the bacteria of the genera Escherichia, Citrobacter and Enterobacter from Gram-negative bacteria of the family Pseudomonadaceae and other oxidase-positive bacteria living in water.
Coli-titer water is measured by the minimum amount of water (ml) in which CGBs are found, if-index - the amount of BGKP contained in 1 liter of the test water.

Determination of the microbial number of air

Quantitative microbiological methods for studying air are based on the principles of sedimentation (sedimentation), aspiration or filtration.
sedimentation method. Two Petri dishes with nutrient agar are left open for 60 minutes, after which the crops are incubated in a thermostat at 37°C. The results are evaluated by the total number of colonies grown on both plates: if there are less than 250 colonies, the air is considered clean; 250-500 colonies - moderately polluted, with more than 500 colonies - polluted.
Aspiration method- a more accurate quantitative method for determining the microbial number of air. Air seeding is carried out using devices (Krotov's device and sampler PAB-1).
Krotov's apparatus is designed in such a way that air seeps through a narrow slit of a Plexiglas plate covering a Petri dish with nutrient agar at a given speed. In this case, aerosol particles with microorganisms contained on them are evenly fixed on the entire surface of the medium due to the constant rotation of the cup under the inlet slot.
After incubation of sowing in a thermostat, the microbial number is calculated

Sterilization Methods

Thermal: steam and air (dry heat)
Chemical: gas or chemical solutions (sterilants)
Plasma (hydrogen peroxide plasma)
Radiation sterilization - used in the industrial version
Membrane filter method - used to obtain a small amount of sterile solutions, the quality of which can deteriorate dramatically under the action of other sterilization methods (bacteriophage, selective nutrient media, antibiotics)

Thermal sterilization methods

Advantages of thermal sterilization methods:

Reliability
No need to remove sterilants from medical supplies
Ease of use of staff
Sterilization is carried out in packages, which allows maintaining sterility for a certain period of time.

Steam sterilization

It is carried out by supplying saturated steam under pressure in steam sterilizers (autoclaves).

Steam sterilization under pressure is considered the most effective method, since the higher the pressure, the higher the temperature of the steam sterilizing the material; The bactericidal properties of steam are higher than those of air; therefore, supersaturated steam is used for sterilization.

Steam sterilization is carried out on textile products (underwear, cotton wool, bandages, suture material), rubber, glass, some polymeric materials, nutrient media, and drugs.

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The total microbial count reflects the total level of bacteria in the water, and not just those that form colonies visible to the naked eye on nutrient media under certain cultivation conditions. These data are of little value for the detection of faecal contamination and should not be considered an important indicator in assessing the safety of drinking water systems, although a sudden increase in the number of colonies in the analysis of water from a groundwater source can be an early signal of contamination of the aquifer.

The total microbial count is useful in assessing the effectiveness of water treatment processes, especially coagulation, filtration and disinfection, with the main task being to keep their numbers in the water as low as possible. The total microbial count can also be used to assess the cleanliness and integrity of the distribution network and the suitability of water for food and beverage production, where microbial counts should be low to minimize the risk of spoilage. The value of this method lies in the possibility of comparing the results when examining regularly taken samples from the same water supply to detect deviations.

The total microbial count, i.e. the number of bacterial colonies in 1 ml of drinking water, should not exceed 50.

Characteristics of water sources and water supply systems.

There are underground and surface waters, flowing and stagnant.

Underground water sources, depending on the depth of occurrence and relationship to rocks, are divided into:

1) soil;

2) ground;

3) interstratal.

Soil water sources lie shallow (2-3 m), actually lie near the surface. They are abundant in spring, dry up in summer, and freeze in winter. As sources of water supply, these waters are of no interest. The quality of water is determined by the pollution of atmospheric precipitation. The amount of these waters is relatively small, organoleptic properties are unsatisfactory.

2. Groundwater - located in the 1st aquifer from the surface (from 10-15 m to several tens of meters). These horizons are fed mainly by precipitation filtration. The diet is not constant. Atmospheric precipitation is filtered through a large thickness of soil, therefore, in bacterial terms, these waters are cleaner than soil waters, but they are not always reliable. Ground waters have a more or less stable chemical composition, they can contain a significant amount of ferrous iron, which, when the water rises to the top, turns into trivalent (brown flakes). Groundwater can be used for decentralized, local water supply, since their capacity is small.

Interstratal waters lie deep in the aquifer, lying (up to 100 m) between two waterproof layers, one of which is the lower one - a waterproof bed, and the upper one - a waterproof roof. Therefore, they are reliably isolated from precipitation and groundwater. This predetermines the properties of water, in particular its bacterial composition. These waters can fill the entire space between layers (usually clay) and experience hydrostatic pressure. These are the so-called pressure, or artesian, waters.

The quality of artesian waters in terms of physical and organoleptic properties is quite satisfactory. Such waters are also reliable in bacterial terms, they have a stable chemical composition. In such waters, as mentioned above, hydrogen sulfide (the result of the action of microbes on iron sulfide compounds) and ammonia are often found, there is little oxygen in them, and there are no humic substances.

Surface water - lakes, rivers, streams, canals, reservoirs. All open reservoirs are polluted by precipitation, melt water, industrial wastewater.

Characteristics of water supply systems:

1.Local (decentralized).

2.Centralized.

For local water supply, the population uses water from underground sources -

Wells, captages (chambers for the accumulation of water from springs and springs). Water source-

square meters of local water supply is used by the population without prior purification, so it must be safe in terms of epidemic indicators, harmless in chemical composition and have pleasant organoleptic properties. Wells are: mine and pine forest (tubular).

The place for the well should be located:

Uncontaminated elevated area.

Remote at least 50m from latrines, latrines, sewerage networks,

barnyards, places of burial of people and animals,

fertilizer depots, above sources of pollution.

For the construction of wells and cappings, aquifers under impermeable rocks should be used.

Requirements for the device and equipment of water intake facilities:

The walls of the well shaft are lined with waterproof fasteners

An earthen castle 2m deep and 1m wide is arranged at the edge of the mine.

On top of the clay, a blind area made of asphalt, concrete, brick is equipped with a slope from the well.

Shed, lid, community bucket needed.

The top of the well is at least 0.8 m above the ground.

There should be a filter layer of gravel with a thickness of 20..30cm.

It is not allowed to raise water with a personal bucket and draw water with a scoop from a public bucket.

Within a radius of 20 m from the well, rinsing and washing clothes, watering animals, washing various items is not allowed.

The area around wells and dams must be kept clean and fenced.

1-2 times a year, the well must be cleaned and drained - for this, in the spring, the well is filled with a 3-5% bleach solution, 1 bucket of a 2% disinfectant solution is added, left for 6-10 hours, then the water is pumped out. The method of continuous chlorination by dosing is also used.

a cartridge with a capacity of up to 1 liter is valid for up to 20-30 days.

Tubular (drilling, Abessinian) wells are small-tubular structures up to 30 m deep, they are installed by drilling, a clay castle is made around, used locally.

Water supply at field camps - imported water, containers 50-70 liters per person, must comply with hygienic standards.

Centralized water supply - water supply - a system of structures that extracts, purifies, disinfects, delivers water to the population. If groundwater serves as water supply and complies with ST 2784-82, then they do not need to be treated.

The plumbing consists of:

Water intake and improvement facility

Clean water tank

Pumping facilities

Water tower

Conduit and distribution network of pipes.

Most often, surface water is used, which must be cleaned, disinfected, since water in open reservoirs is prone to contamination.

dirt.

Water purification and disinfection methods:

Stage 1 - clarification and discoloration, is achieved by long-term settling, therefore, at waterworks, chemical treatment with coagulants is used, which accelerate the sedimentation of suspended particles.

Stage 2 - water filtration through a layer of granular material (sand, anthracite).

Filtration is slow and fast.

Slow - carried out through special filters (a concrete tank, drainage is arranged at the bottom, a supporting layer of crushed stone, pebbles, gravel is loaded on top of the drainage - thickness - 0.7 m. A filter layer is loaded onto the supporting layer - 1 m. Filtration rate 0.1-0.3 m/h

Fast filters - thickness 0.8m, filtration speed 5-12m/h. The filters are cleaned by supplying water in the opposite direction at a speed 5-6 times faster than filtration.

Stage 3 - disinfection, which is carried out by chemical and physical methods.

Chemical methods:

1.chlorination use chlorine gas, other chlorine-containing substances.

When a chlorine-containing reagent is introduced into the water, 95% of it goes to the oxidation of substances, 2-3% of the total amount of chlorine is spent on the oxidation of bacterial cells.

The amount of chlorine, which, when chlorinating 1 liter of water, is consumed for oxidation within 30 minutes, is called the CHOLOR ABSORPTION of water. At the end of the chlorine binding process, residual active chlorine appears in the water. Its appearance confirms the completion of the chlorination process. If the residual active chlorine in the water is 0.3-0.5 mg / l, this is a guarantee of the effectiveness of disinfection.

There are several ways to chlorinate water:

Chlorination at normal doses

Chlorination with ammoniation - an ammonia solution is introduced into the water, and after 2 minutes a chlorine solution.

Double chlorination - chlorine is supplied twice - 1 time before the settling tanks, 2 times after the filters.

Perchlorination - deliberately large doses of chlorine 10-20 mg / l.

2. ozonation - when ozone decomposes in water, free radicals HO / 2, OH are formed, which are strong oxidizing agents and determine the bactericidal properties of ozone. Ozone bleaches and eliminates tastes and odors,

does not form toxic compounds in water.

Physical methods:

Boiling - 3-5 minutes of boiling is a complete guarantee of safety, but it is necessary to change the container daily, because. in boiled water m / o multiply intensively.

UV irradiation - does not change the organoleptic properties, destroy viruses, spores of bacilli, helminth eggs.

Exposure to ultrasonic waves - disinfection of domestic wastewater.

high frequency currents

Gamma rays - instantly destroys all types of m / o, but is not used in practice.

Physical methods do not change the chemical composition of water.

Special methods for improving the quality of drinking water.

Deodorization - elimination of odors by treatment with oxidizing agents and filtration through activated carbon.

Iron removal - by spraying water for the purpose of aeration in special devices - cooling towers, iron oxide hydrate is formed, which is deposited in the sump.

Water softening is achieved by filtration through ion-exchange filters.

Desalination - by successive filtration, water is freed from all salts dissolved in it (evaporation, freezing, electrodialysis).

Defluorination - filtration through ion-exchange filters.

Foration - add fluorine

Protection of water sources.

A new regulatory document SanPiN - 2.1.4.559 - 96 has been developed and approved

On the need to harmonize Russian standards with WHO recommendations,

New scientific knowledge about the impact of drinking water on human health, as well as the widespread deterioration of water quality in surface and groundwater

sources.

According to the “Water Code of the Russian Federation, to maintain facilities in a state corresponding to

In order to meet environmental requirements, water protection zones are established to prevent pollution and depletion of surface waters, as well as to preserve the habitat of flora and fauna objects.

Sanitary protection zones (ZSO) are organized on all water pipelines, regardless of departmental affiliation, supplying water from both surface and underground sources. ZSO - are organized as part of three belts:

According to the legislation, this zone is divided into 3 zones:

1) high security belt;

2) belt of restrictions;

3) observation belt.

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