How to chlorinate drinking water. Disinfecting water with chlorine. Bactericidal properties of chlorine and hypochlorous acid

is a process in which water is exposed to chlorine. In this case, the water is purified, but a number of by-products are also formed that are very harmful to humans.

Chlorine is worst enemy our modern times from the time it began to be added to drinking water as a disinfectant ( since 1904). By preventing one disease, it causes other, more terrible diseases (for example, cancer, premature aging, heart disease, etc.). Chlorine is widely used to disinfect water, but at the same time it is a dangerous carcinogen.

Water chlorination, on the one hand, saved humanity from the great risk of contracting infectious diseases or epidemics, but on the other hand, scientists in the 70-80s discovered that there is harm from chlorinated water, manifested in the accumulation in oneself carcinogenic substances. Among the population that consumes chlorinated water, cases of cancer of the larynx, esophagus, breast, rectum, etc. have been found. This is due to the fact that after the interaction of organic substances with chlorinated water, they form chemical substances (trichloromethanes), which are carcinogenic. This fact has been proven experimentally by scientists from many countries. It has also been noted that chloroform causes cancer even in rats.

The effect of the harmful effects of chlorine on the human body can be initiated in two ways:

1) when chlorine enters the human body through the nasopharynx;

2) when chlorine penetrates through the skin person. Scientists all over the world are studying this problem.

They associate many dangerous diseases with the entry of chlorine into the human body or harmful products, which are obtained after chlorination of water. These diseases include: liver cancer, colorectal cancer, stomach cancer, bladder cancer. But not only the organs that take part in digestion can be damaged.

Chlorine can cause heart disease, anemia, high blood pressure, atherosclerosis. Chlorine also dries the skin (for example, you can remember the feeling of “tightness” of the skin after you have been in the pool), irritates the mucous membrane of the eye, destroys the structure of the hair (it becomes dull, lifeless, brittle and begins to fall out more often). American epidemiologists conducted a study in which they compared a map of water chlorination and a map of the distribution of cancer of the digestive organs and bladder. A direct relationship was identified - the lower the concentration of chlorine in the water, the less common such diseases are.

But such evidence and conclusions have more than once been harshly criticized by other scientists who do not agree that there is harm from chlorinated water. And they confirmed the theories with facts. One of the arguments is that experimental animals, in laboratory conditions, received a higher dose of chlorine than in tap water. Another argument was that both chlorine and chloroform disappear if water is boiled. Both scientists are right in their own way. But still, scientists are still scratching their heads on this issue. And chlorine is still the cheapest and most effective means of disinfecting tap water.

Chlorine Toxins exhibit a slow and deadly effect on the human body. Cleansing drinking water from chlorine in no way solves the problem, because many dangerous compounds that are formed in water during chlorination enter the human body through the skin, during bathing and visiting the pool. There is an opinion that taking an hour-long bath with water that contains excess chlorine corresponds to 10 (or more) liters of drinking water with chlorine.

Information about the second side of the coin, that is, the harm of chlorinated water, was obtained only in the late 70s. Scientists have proven a direct relationship between cancer and water quality. Previously, it was believed that water with chlorine was not harmful to human health. According to many researchers, 30-50% of malignant tumors can be associated with the consumption of poor-quality water.

So, everyone must decide for themselves what to do. It is possible to protect yourself from the harmful effects of chlorine. First of all, you need to install a water purification system or use water filters. Proponents of water with chlorine are confused by the fact that in villages and villages where people do not drink tap water, they encounter cancer much less often than in megalopolises and cities. But such a connection is not entirely obvious due to the fact that a number of other equally important factors are not taken into account.

To ensure that chlorine is removed from water use good filters , which will remove all impurities and make the water taste good. Read more about water purification. Water filters are presented in a wide range and according to good prices. At the same time, do not forget that water passed through the filter is cleared of impurities, including chlorine, which kills bacteria. So, we do not recommend stocking up on such water, because bacteria, in the absence of a “preservative” - chlorine, will multiply in warm and clean water that is pleasant for them very quickly. If you still decide to store purified water for more than a day, then keep it in a container made of neutral material - food-grade plastic or glass.

Of course, the harm of chlorinated water is obvious, but you can simply take care of your health and then no chlorinated water will take you. For example, it is useful to consume oxygen cocktails, which Lately often offered in kindergartens for children. Well, if you do become ill, for example, have a cold, then you will have to undergo treatment. By the way, a compressor nebulizer is perfect for these purposes, which will allow you to deliver medications to the very depths of the bronchial tree.

Treatment of drinking water with chlorine is one of the main stages of water treatment. Since opening unique properties the most common septic tank, and to this day, debates around the effectiveness and safety of using chlorine compounds do not subside even for a minute.

The technology of water chlorination was discovered in the middle of the last century. For several centuries, chlorine, due to its unique oxidizing properties, has been used as an antiseptic and a substance that can combat the unpleasant taste and odor of liquids.

The dangers of chlorination

It has now been established that almost all chlorine compounds are capable of forming trihalomethanes (THMs). Chloroform, dichlorobromomethane and dibromochloromethane are derivatives of the reaction of chlorine and naturally occurring organic compounds. The process of formation of toxic compounds intensifies with increasing pH levels.

The concentration of THMs can be significantly reduced at the stage of water purification from organic compounds. Due to the absence of one of the most important components of the reaction, the maximum permissible concentration of toxic compounds does not exceed the established limits.

Drinking water chlorination technology

Today, many water treatment plants use liquid or gaseous chlorine (alternatively, sodium or calcium hypochloride). When one of the most common antiseptics gets into water, a mixture of hypochlorous and hydrochloric acid is formed:

WITHl 2 + H 2 O = NOSl + NSl

Hypochlorous acid then dissociates, forming hypochlorite ions, which have bactericidal properties:

NOSEl→Н + +OSl -

The sum of Cl 2 +HOСl+OCl- is called free active chlorine.

Chlorination of water with chlorine gas

The reagent is supplied through a special dispenser. The gas is supplied under high pressure in a nitrogen environment through pipes. In the event of an accident, this design allows you to quickly neutralize the chlorine.

Chlorination of water with liquid chlorine

Fig.2 The reagent is supplied from cylinders (I) to the intermediate supply cylinder (II). The distribution system (1) then pumps a mixture of gas and drinking water through a pipeline (2).

Fig.2

Depending on the initial composition of water, all methods of disinfection using chlorine compounds are divided into two groups:

Post-chlorination,

Prechlorination.

The main purpose of prechlorination is to remove organic compounds and reduce the concentration of THMs. Dechlorination is not carried out at this stage.

Post-chlorination of water is the final stage of water treatment. If necessary and occasional bacterial contamination, the septic tank dose is increased to 1.0-10.0 mg/l. Excess chlorine is removed by dechlorination (treatment with sodium thiosulfate or sulfite, sulfur dioxide, activated carbon) or aeration.

Advantages and disadvantages of chlorination:

Simplicity of the method

Efficiency of chlorination,

Simultaneous oxidation of iron and manganese,

- “accompanying” removal of unpleasant taste and odor of water,

Prevention of algae growth and biofouling of filters,

High cost-effectiveness of the method (compared to ozonation).

"-"

Increased requirements for storage conditions and transportation of chlorine compounds,

The need to comply with strict safety measures,

Formation of by-products (THM),

Potential threat to human health in case of leakage of chlorine compounds,

When treating water with chlorine, compliance with the permissible concentration of the septic tank, which is measured during laboratory tests, plays an important role. An indicator of the correctly chosen dosage of the reagent is the content of residual chlorine, regulated by GOST 2874-73*.

*According to GOST requirements, the concentration of residual chlorine in water before it reaches the consumer should not exceed 0.3-0.5 mg/l.

Sources used:

1. Guide to water supply hygiene, ed. S.N. Cherkinsky

2. Kobrina V.N. Chemical methods of water preparation (chlorination, ozonation, fluoridation).

Every city resident uses water from crane to cook food, wash dishes, wash, do laundry and keep your home clean. Water is the basis of life. Meanwhile, there is probably no person today who would not be informed that tap water is the source of all diseases. According to WHO, the cause of human infection with various infections in 85% of cases is water, including that which enters our homes through the city water supply network.

From the quality of the water that flows from crane, our health depends. However, the composition of this water rarely meets the standards; rusty and dirty tap water has become commonplace for residents of many cities. After all, the pipes laid decades ago have long since rusted and become overgrown with moss and unknown vegetation. In addition, in many cities, water is supplied to homes from surface sources, and it must be purified and chlorinated in order to prevent the spread of cholera, typhoid, plague, dysentery and other infectious diseases.

Unfortunately, despite the development of new technologies, water is disinfected with ultraviolet light today only in a few regions of Russia; mainly for disinfection, a chemical compound called hypochlorite is added to the water. If after exposure to ultraviolet radiation, water remains healthy, then after chlorination it has a bad effect on the esophagus and gastrointestinal tract, contributes to the exacerbation of asthma, allergies, heart disease and increases blood pressure.

According to Dr. Herbert Schwartz from Cumberland College, water chlorination is so dangerous to health that it should be banned. He considers the consequences of adding chlorine to water to be the development of cancer, heart disease and premature aging. Dangerous compounds that form in water after chlorination enter the human body not only after drinking, but after taking a bath, shower, visiting the pool and washing dishes.

Horror stories about harmful things influence of tap water There have been a lot of developments in health recently. But is chlorinated water from the tap really so dangerous to health or is this just another advertising gimmick by bottled water and household filter manufacturers? Without determining the composition of tap water, it is impossible to answer this question. Water quality measurements are carried out by Rospotrebnadzor, whose employees regularly take water samples at various points in the city and conduct analyzes to determine its compliance with sanitary norms and standards.

In one liter of water allowed the content of the following substances: chlorides - no more than 350 mg, nitrates - no more than 45 mg, sulfates - no more than 85 mg, and water hardness should be from 3.0 mg to 3.5 mg per liter. If analyzes of tap water meet these standards, then drinking it is considered not harmful to health. However, water of increased hardness leads to the formation of stones in gallbladder, urinary tract and kidneys, salt deposition in joints.

High content chlorides and sulfates negatively affects digestion and work of cardio-vascular system, disrupts metabolism in the body. Increased iron content in water can cause skin diseases, worsen blood composition and heart function. According to experts, tap water that meets all sanitary standards is safer for health than spring or well water. Tap water is regularly tested, so there are no pathogenic microbes in it, and to provide such a guarantee for residents who use water from natural sources, no one can. In addition, spring water in many regions is hard, which contributes to the development of urolithiasis.

From bacteria and microbes You can get rid of it in water by simply boiling it, and tap water is treated with chlorine for this purpose. It is estimated that over the course of 50 years of life a person drinks more than 45 tons of water, but if he lives in a city and uses tap water for drinking, then along with it 16 kg of bleach, 2 kg of nitrates, 14 grams of iron enter his body during this period of life and 23 grams of aluminum.

According to opponents consumption of tap water, all these dangerous substances accumulate in the body and cause the development of chronic diseases after 50 years of age. But these diseases affect not only city residents; no fewer citizens of honorable age who live in rural areas and drink spring water are affected by them. Therefore, it is wrong to assume that all human illnesses come from tap water. Healthy image life, balanced diet, giving up bad habits and getting enough sleep help maintain health for many years, including for people who have been drinking tap water all their lives.

If you are already used to drink bottled water or pass tap water through a filter before drinking, then know that you still won’t be able to fully protect your body with their help. The fact is that the majority of water in bottles is fake, and there is no universal filter for water purification. As studies by US scientists have shown, the use of activated carbon filters to purify chlorinated water does not make the water healthy.

When purifying water through such filter Small particles of coal enter the water, which, when boiled, form a toxic poison - dioxin. Therefore, before switching completely to bottled water, first check the quality of your tap water by conducting an analysis in a chemical laboratory. If it meets the required standards, then maybe there is no need to rack your brains over the question of whether it is dangerous to health? To get rid of high chlorine content, collect tap water in clean containers and leave it to stand for a day.

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Impossible. For these purposes, biological analysis is carried out. Indirect signs of poor-quality water include cases of illness in households, an unpleasant odor from the source, a changed appearance and even its taste. These signs should suggest that it is time.

Contaminants penetrate into water for various reasons, which affect the appearance of an unpleasant odor and color changes. In such cases, it is necessary to disinfect the water

The cause of pollution is the ingress of garbage and dirt, carcasses of birds and animals, sewerage running next to a well, runoff of agricultural chemicals from nearby fields, floods, and excessive melting of snow. If the presence of pathogenic microbes in the well is suspected, drinking water is disinfected.

Chemical methods

If chemicals or their compounds are used to destroy pathogenic microbes, then they say that chemicals are used. These include:

• Treatment with iodine - 3 drops per liter
• Treatment with potassium permanganate - 1 g per bucket
• Use of aluminum alum
• Use of silver or silicon
• Ozonation
• Chlorination

Well water purification or well disinfection is carried out by chlorination and potassium permanganate.

Using chlorine for disinfection

Chlorination of water is the most common method of disinfection. The event is carried out using liquid, solid or gaseous forms chemical element and its connections.

Well water can be disinfected using bleach.

For disinfection the following is used:

1. Chlorine dissolved in water - the formula for chlorine water contains chlorine molecules, hypochlorous and hydrochloric acids. Is used for
2. Solid compound - bleach
3. Liquid solution for household needs “Belizna” - water is disinfected with sodium hypochlorite, which is included in

Once a year, well water is completely disinfected. To implement it, the following steps are carried out:

• Draining a well
• Checking the integrity of the shaft and, if necessary, restoring it
• Mine disinfection
• Bottom disinfection
• Installation of a new bedding
• Water disinfection

For these purposes, special chlorine-containing preparations are purchased in a store that sells disinfectants. If it is necessary to carry out emergency chlorination of drinking water, then “Belizna” or bleach is used.

Disinfection is organized according to the following scheme:

1. When pumping water from the well is completed, its walls are cleaned with bleach. For work it is convenient to use a spray bottle or a roller on a long stick. A regular mop wrapped in a cloth will do. The solution can be applied with a sponge. “Whiteness” is diluted at the rate of half a liter per bucket
2. carried out after it has filled the mine again. A solution of “Belizna” is used - 1 liter per ring or bleach - 200 g, which is diluted with cold water
3. The prepared products are poured into the well, the water is mixed with a bucket
4. The top of the well is covered with film and closed with a lid.
5. Disinfection of wells takes 12-24 hours, after which the water is pumped out several times. A sign that it can be used again will be the absence of the smell of bleach from the taps.

If bleach is used for disinfection, microbes are guaranteed to be destroyed, and after treating the source, it is advisable to submit the water for bacteriological analysis.

To clean the well, you need to use tools such as a ladder, brushes, etc.

Disinfection with potassium permanganate

You can disinfect a well with potassium permanganate. Processing is a gentle method. A teaspoon of powder is diluted with a bucket of water and poured into the well. The well is pumped out 2-3 times. Silicon chips placed in a nylon mesh are placed at the bottom. Silicon disinfects water.

Ozonation

Disinfection of water using ozone allows you to destroy any pathogenic microorganisms contained in the water. The cleaning process does not affect acid-base indicators, does not form additional salts, that is, has no side effects. Ozonation devices are installed in two ways: after the source and through coarse filtration, or under the sink.

In addition to disinfection, ozone treatment allows you to get rid of manganese, hydrogen sulfide. Solid fractions are filtered by a built-in ozonizer. You can drink water after the ozonizer within 20-25 minutes. During this time, the ozone will have time to decompose.

Installing an ozonizer is an expensive undertaking, which, in addition to financial investments, requires careful monitoring of the operation of the equipment.

Use of tablets

If necessary, tablets for water and well purification such as Aquatabs, Ecobreeze, and Septolite are used. They contain chlorine. Preliminary disinfection of the mine is carried out with a solution of 4 tablets per bucket. “Ecobreeze” or “Septolite” are used.

Half an hour after cleaning the walls, the contents of the well are disinfected. Aquatabs tablets are used at the rate of 40 g per cubic meter. The solution is poured into the well, which is tightly wrapped with film and covered with a lid. After 6 hours, the condition of the water is checked. If it does not smell of chlorine, then water disinfection tablets are additionally added in the amount of 10 g per cubic meter. After 4 hours, pumping of the well begins.

For any type of cleaning using chlorine, it is recommended to boil and settle well water for the next two days after treatment.

Before you start cleaning the well, you need to pump out the water using a pump.

Other chemical cleaning methods

Iodine, silver, table salt, aluminum alum are used for individual cleansing. The prepared solutions are used for drinking half an hour after mixing water with any of the products.

Physical cleaning methods

You can disinfect water in the following ways:

• Boiling - carried out for 10 minutes, and for very dirty water half an hour
• Filtration
• Ultrasound
• Ultraviolet

These are physical methods of water disinfection, including special attention deserves ultraviolet cleaning.

Installing UV systems for disinfection is one of the most promising methods. This device uses only the action of light in the complete absence of additional reagents. The electronic supply system is adjusted in such a way that a certain amount of liquid automatically enters the water disinfectant and automatically leaves it after cleaning.

Ultraviolet light is destructive for all types of microbes - vegetative and spore-bearing. The UV disinfection method has no upper limit on the dose of radiation installed, so it is selected for any concentration of pathogenic microorganisms.

In terms of costs, the method is between chlorination and ozonation. Ultraviolet lamps for water disinfection, they fade over time. Their maintenance is 10% per year of the installation cost. The second disadvantage of UV disinfectants is the possibility of re-contamination of already purified water.

The figure shows the operating principle of the water purification unit

The use of UV rays to disinfect water is not the only way their applications. Ultraviolet disinfection of wastewater is carried out, which prevents contamination of the aquifer located close to the surface.

Combined cleaning

Disinfection is a complex process. For achievement best results are used combined methods cleaning, that is, physical and chemical methods are combined. Filtration and ozonation, ultraviolet irradiation followed by treatment with chlorine and other combinations allow for high-quality disinfection of well water.

If the water smells bad

You definitely need to pay attention to how the water smells. The absence of visible contamination does not guarantee its cleanliness. An unpleasant odor from a water source can reveal many things:

• If the water in the well smells like rotten eggs, then it contains hydrogen sulfide. The compound is formed by rotting organic matter. The smell will not go away on its own, so you need to find out the cause and get rid of it. Hydrogen sulfide is toxic and hazardous to health
• If the water from a well smells like a swamp, then the reason for this is sulfur pyrites. present in water sources that are fed from a vein located within the peat bog

You should not drink water that smells of sulfur - first you need to eliminate the cause of the smell, that is, the specific type of microorganism that causes it. The following methods are used to eliminate hydrogen sulfide:

1. - hydrogen sulfide molecules are retained by the membrane
2. Chemical - purification and disinfection of water from hydrogen sulfide is carried out with sodium hypochlorite
3. Aeration - oxygen is used as an oxidizer, followed by filtration of sulfur fractions that precipitate

There are times when water from a source has no odor, but water from a boiler stinks. The cause is colonies of microorganisms that have settled inside the heating device or in the pipes. The problem is eliminated by disinfection with bleach or by heating the unit overnight. The smell of hydrogen sulfide from the boiler will cease to appear if the device is constantly used and heated.

Why is the water bitter?

Often spoiled foods have a bitter taste, however, the reason for the bad taste lies in another area. Microorganisms have nothing to do with this. Bitter water in a well occurs due to its excessive hardness. Magnesium and calcium salts, which are present in large quantities in the source, threaten the formation of kidney stones, damaged hair, and damaged skin. Water becomes hard when passing through limestone rocks. Cleaning water from a well from lime is carried out in the following ways:

• Filtration using reverse osmosis membrane
• The ion replacement method draws out calcium and magnesium compounds, leaving them on a special filter resin
• Tabletop filter jug ​​softens water by passing through carbon powder
• Boiling leaves salts on the walls of electrical appliances

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Disinfection and well cleaning help restore, maintain or improve the quality of the water used. Constant monitoring is necessary to prevent severe illness and slow poisoning of the body. Provide proper care and operation of the source are assisted by filtration systems and available methods disinfection based on physical, chemical and combined methods.

We use tap water every day. We wash ourselves with it, we drink it. Often we don’t even boil it. How safe is it for health? Rospotrebnadzor data on the quality of drinking water and the cleanliness of the water supply system sometimes does not inspire optimism.

How water is purified

Experts from the World Health Organization are confident that there are few bodies of water left in nature whose water is safe and beneficial for humans. Most often, large and small cities take water from rivers and reservoirs that have already been polluted. Therefore, the water is first purified at special stations. It is chlorinated, ozonated, coagulated, settled, filtered, chlorinated again, and only then does the water go into the water supply.
During snow melting and floods, I additionally treat the water with activated carbon and potassium permanganate or additional chlorination.

Chlorination

It is around chlorination that many copies have been broken. Chlorine kills any bacteria - even cholera, dysentery and typhoid fever, but it also harms humans. Chlorine dries the skin and is dangerous for allergy sufferers and people prone to asthma.
Doctors are concerned not so much about residual chlorine as about its compounds. For example, Roskontrol experts believe that when chlorine reacts with organic substances, trihalomethanes are formed - carcinogens that can contribute to the formation of cancer cells.

When boiling chlorinated water, dioxins are formed - toxins that suppress the human immune system. These impurities can lead to liver and kidney disease and other health complications. Of course, there will be no immediate effect from them, but in the long term, health can be undermined.
Dr. Herbert Schwartz from Cumberland College (USA), considers water chlorination so dangerous that it needs to be banned.

Pollution from water supply

But that's not all. From stations cleaned, disinfected and safe water, corresponding to all SanPiNs, enters the water supply system and passes through rusty, old, and sometimes leaky pipes several kilometers to the apartment. In Moscow alone, the total length of the water pipeline is 9,000 kilometers. This is more than the distance from the capital to Vladivostok. Along the way, the water washes away dirt and rust from the pipe walls.

As a result, a “cocktail” of chemical compounds pours out of the tap. It is not for nothing that SanPiN lists the maximum permissible concentrations of these substances on almost 20 pages.

Water can and most often contains: chlorides, sulfates, sulfides (hydrogen sulfide), iron, manganese, ammonium (ammonia), silicon and aluminum. There may also be benzopyrene, benzene, cadmium and magnesium, nitrates, pesticides, phenols, surfactants and petroleum products.

And this despite the fact that in Moscow, for example, microbiological indicators of water are checked 2 times a day, organoleptic indicators - up to 12 times, and indicators for residual chlorine - every hour. Every day, 1000 chemical, 100 bacteriological and 20 hydrobiological analyzes are carried out at the stations.

According to research by Oleg Mosin, candidate of chemical sciences, tap water leaving stations in Moscow meets the standards and, in some respects, exceeds the water in European cities. But even he expresses concerns about the quality of water coming from the tap and believes that the situation in the regions is worse.
Yes, all these dangerous substances are present there in extremely small doses. But they are present!

Don't panic

But let’s not rush and write ourselves down as sick.
According to Rosstat, in 2011 the average life expectancy in Russia was 69.83 years. In 2013, it increased to 70.8 years, and in 2014 – to 71 years, which exceeds the 1990 level.

Thirdly, it is with drinking water the population receives such an essential microelement as fluoride - it is added to the water.

Lack of fluoride causes problems with teeth and joints, suppresses hematopoiesis and immunity, and causes problems with the healing of fractures.

Fourthly, in addition to fluoride, a person in microdoses needs substances such as arsenic, the lack of which causes the development of allergic reactions, chromium, which is involved in the process of carbohydrate metabolism and is necessary for the functioning of the heart, silicon, without which hair falls out. Vanadium is also needed, without which diabetes and atherosclerosis can develop.

In addition, ordinary tap water contains other salts that are vital for humans. In 2003 in Rome at a symposium of the Center environment and health sounded Interesting Facts. It turned out that residents of the northern regions Irkutsk region Those who drink harder water, all other things being equal, are less likely to suffer from goiter, high blood pressure, stomach and intestinal diseases, and pregnant women and newborns have fewer complications.

What to do?

If you think the water coming from your tap is of poor quality, you can switch to bottled water. But only if you are confident in the manufacturer. After all, the fact that it is bottled water manufacturers who most often talk about the dangers of tap water cannot but be alarming.

To make tap water safer, you need to drain it for a few minutes, then let it sit for at least a day and only then filter it.

Not all filters are equally useful. For example, US scientists are sure that carbon filters are harmful. Coal enters water and forms dioxide when boiled.

Remember that bacterial water purification is carried out by filters that cost more than $300.
But both scientists and doctors agree that any filter is better than nothing. Just don’t forget to wash and change the filters, otherwise the positive effect may turn negative.