Manganese. Manganese water contamination

Manganese water contamination - a serious problem when preparing water for use.

The source of manganese pollution is the rise of deep waters during tectonic movements of the earth. But this is not as common a case as pollution by wastewater from lands where manganese-containing fertilizers are used. Manganese is a heavy metal and increasing its concentration can have serious consequences for the body. At the same time, an increase in the amount of manganese in water can be determined by appearance and taste only at a very high level of its concentration. Then the water becomes cloudy with a yellowish tint and tart.

In the body, manganese promotes blood-forming functions and regulates the activity of the gonads and pituitary gland. However, the amount of manganese required for these functions is very small. Any excess leads to serious consequences. The dose that has toxic properties for humans is equal to 40 mg per day. The lethal dose has not yet been determined. In principle, this element is considered the least toxic of all heavy metals, and its content in natural conditions is rarely overestimated. Typically, all poisonings occur as a result of regular technological industrial emissions. Symptoms do not appear immediately. Only after several years can one notice a clear clinical increase in the accumulation of manganese in the body.

Maximum permissible concentration manganese in drinking water and water for domestic use in Russia, Ukraine and other CIS countries is 0,1 milligram per liter of water. In some European countries the requirements have been tightened.

Harm to human health

Firstly An increased content of manganese leads to disturbances in the functioning of the nervous system. Symptoms include fatigue, drowsiness, and memory loss. The body cannot absorb excess manganese.

Secondly, an increased content of manganese in water can cause an elementary allergy to both manganese and other substances in the complex.

Third, manganese can cause urolithiasis, blockage of blood vessels, disruption of the vegetative-vascular system, problems with the liver and endocrine glands. All these symptoms are caused by deposits of heavy metal salts.

Fourthly, due to disruption of vascular function coupled with allergies, manganese provokes pulmonary and bronchial diseases.

An excess of manganese is one of the reasons for increased fragility and brittleness of bones.

In rare cases, excessive concentrations of manganese cause "manganese madness." The person behaves inappropriately, aggressively, inconsistently.

Harm to household appliances and communication networks

Unlike an excess of iron in water, manganese does not entail such severe consequences for equipment and communications.

Its excess is expressed in stains and brownish sediment on the surface of plumbing fixtures. Over the long term, manganese deposits can clog pipes. The only difference is that manganese clogs are much more difficult to remove. Sometimes manganese can become a dye during washing and ruin things.

Removing manganese from water

The amount of manganese in water is determined in a chemical laboratory. This factor cannot be determined by appearance, as mentioned above.

Oxidation is used to purify water from manganese. With its help, manganese is converted from an inactive divalent form to a tri- and tetravalent one. This manganese then falls out in the form of sediment, which in turn is safely removed by the filter.

Methods used to extract manganese salts and ions from water:

1. Aeration followed by mechanical filtration;

2. Reagent treatment using potassium permanganate followed by coagulation with weak acids, such as silicic acid. Used at high concentrations of pollutants.

3. Reverse osmosis is used when there are very high concentrations of manganese in the source water.

4. Filtration through a charge on which a layer of 4-valent manganese hydroxide was applied.

The prevalence of manganese is quite high, it ranks 14th among commonly occurring minerals. It is present in many products and naturally in water, since it dissolves well. And, like any element that comes into food, it can be beneficial or harmful. So, purifying water from manganese and maintaining it at a satisfactory level becomes highly important.

GOST: manganese in drinking water

  • in centralized systems – ≤ 0.1 mg/l;
  • manganese in water from wells and other open sources – ≤ 0.5 mg/l.

In nature, manganese can form up to 8 types of oxides, from MnO to Mn5O8, and is part of copper and iron ores. The formation of oxides depends on the composition of the medium and external physical parameters. The most stable oxide is MnO2, which is also the most common in the bowels of the earth, and is called pyrolusite.

Due to the widespread use of the mineral in metallurgy and chemical production, special attention is paid to its content in industrial wastewater. The amount of manganese in wastewater should not exceed 0.01 mg/dm3.

Manganese in water: effect on the body and visual determination of its presence

As is known from medical practice, even a toxic substance, in a small amount, can have a beneficial effect on the body, but exceeding its norm will lead to irreparable consequences.

Beneficial functions of manganese in the body

Depending on age, permissible daily doses vary and are:


Manganese can be obtained from both water and food. The territory of Russia does not have areas with poor Mn content; there is even an excess of manganese in the water. The participation of the mineral in the physiological processes of living organisms is irreplaceable. Its main functions:

  • adjusting glucose levels, inducing the synthesis of ascorbic acid;
  • inhibiting the development of diabetes mellitus;
  • support the activity of the nervous system and brain;
  • production of cholesterol and assistance in the functioning of the pancreas;
  • formation of connective, cartilage and bone tissue;
  • regulation of lipid metabolism and prevention of fatty liver;
  • involvement in cell division and renewal;
  • inhibiting the activity of cholesterol and preventing the growth of “plaques”;
  • activation of enzymes for the body to absorb vitamins B1, C and biotin.

Can be used as an antioxidant when interacting with Fe and Cu. Manganese is retained in the body by P and Ca. Eating foods high in carbohydrates leads to rapid depletion of Mn reserves in the body. The amount of manganese in water can have both positive and negative effects. In some conditions, a deficiency of manganese occurs; the norm in water does not cover its daily requirement for nursing mothers and athletes.

Harm from excess manganese in water

What is dangerous about manganese in water for physiological functions is that it reduces the absorption of iron and competes with copper, which results in anemia and drowsiness. Considerable harm is also caused to the central nervous system, expressed in decreased performance and the development of early amnesia. The heavy metal Mn can damage the lungs, liver and heart in large doses, and stop lactation in nursing women.

Health is one of the main aspirations of a person, but everyday problems created by manganese compounds can be quite annoying. Visual determination of manganese in drinking water is carried out by inspecting plumbing fixtures and utensils that are in long-term contact with tap liquid.

Most often, the mineral accompanies divalent iron and forms insoluble compounds with it. Black deposits form on plumbing fixtures and food utensils, scale quickly builds up in electrical appliances, and the permeability of pipes decreases. Too high a level of contamination is visible already when drawing water from the tap, and can even be tasted and smelled. In these cases, it is necessary to immediately do a water analysis; manganese and iron should be the main parameters studied.

Water purification from iron and manganese

In tap or artesian water, the mineral is found in the form of a divalent positive ion (Mn2 +), which is highly soluble in liquids. To remove manganese from water, it is converted into insoluble forms - trivalent or tetravalent. Dense sediment is removed with granular catalytic media or ion exchange resins.

Manganese water filters and filtration methods

Methods used in demanganization:

Aeration. It is used when there is divalent iron in the water. Under the influence of aeration, iron oxidizes and turns into hydroxide. The resulting compound binds divalent manganese and precipitates it. Solid impurities are filtered through quartz sand.

Catalytic oxidation. It is carried out with 4-valent manganese hydroxide.

Oxidizing reagents. Ozone, sodium hypochlorite, chlorine itself and its dioxide are used here.

Ion exchange. It is performed by two types of resins: anion exchange (OH–) and cation exchange (H+).

Distillation. Based on the difference in boiling temperatures of water and its impurities. Water mineralization is required after the procedure.

Depending on the results of the analysis for the volume of manganese in water, a filter with a certain filtration method is selected. Or water purification is carried out by a complex of filter components that consistently reduce liquid contaminants.

Clean drinking water is the key to the health of any person. However, neither well nor tap water can guarantee the absence of contamination.

And if central water supply systems are equipped with industrial filtration systems, then water extracted on your own site usually needs high-quality purification. One common type of contaminant is manganese in well water.

Manganese content standard

An increased content of manganese in water from wells, although this phenomenon is not very common, is by no means rare. This substance is a heavy metal and is most often found in water along with iron.

By the way, it is because of manganese that the iron contained in water turns into a trivalent insoluble form. Typically, this element enters wells from high water or from layers saturated with ore.

But in any case, it is better not to exceed the maximum permissible content standards. After all, this is fraught with serious consequences.

Why is high manganese content dangerous?

This element has a negative impact on the plumbing system, household appliances and human health.

Impact on the plumbing system:

  • manganese leaves deposits in water pipes, which reduces their service life;
  • forms scale on electrical appliances;
  • Contact with contaminated water leaves stains.

Health effects:

  • fatigue increases, memory decreases, and the general condition of the nervous system worsens;
  • has a negative effect on the condition of the skeleton;
  • promotes the development of allergic reactions;
  • manganese tends to be deposited in the body, so it gradually becomes slagged.

Considering the serious consequences that a high content of this substance entails, water must be cleaned of manganese. However, you need to understand that first of all, you need to have your water analyzed in a laboratory. And already knowing the exact contents, you can plan cleaning measures.

Manganese removal

In fact, water purification from manganese is carried out in the same way as from iron. Because this element belongs to metals and is contained in a liquid in an insoluble form; the main task is its oxidation and subsequent filtration. And this allows you to do the installation yourself.

Aeration

The essence of the method is to saturate the water with oxygen. Due to this, iron and manganese are oxidized and converted into a soluble form. Next, the water is either settled or passed through a system of cartridge or sorption filters. There are two types of aeration:

  1. Pressure.
  2. Non-pressure.

The pressure system is more expensive and consists of an aeration column and additional filters. Oxygen is supplied to the column under high pressure, which actively oxidizes it. Excess gases are removed through a special valve.

Aeration column

The advantages of this system are its efficiency and autonomy - all processes are controlled by an automation unit. It also does not require the installation of additional equipment, since as a result of cleaning, pressure in the system is not lost.

A non-pressure aeration system is considered a more simplified version of a pressure one. In this case, a large capacity tank is used as a basis. Usually this is 700 - 1000 liters. Water enters it through special sprayers with small nozzles.

Gravity aeration

The sprayer itself is installed in such a way that there is at least 1 meter between it and the surface of the water. Thanks to this, the water has time to mix well with air and oxidize.

Additionally, a low-power compressor is installed, which supplies air to the container. Since the water supply is broken by the use of a sprayer, a pumping station is required to pump water back into the system.

In general, both aeration options can successfully remove manganese and iron from water. An additional advantage is the removal of hydrogen sulfide impurities.

Settling and mechanical cleaning

Mechanical cleaning is based on the use of cartridge systems. These are coarse filter systems, so they are only suitable for filtering out large particles. Their use is justified only in conjunction with other types of cleaning, because... they are able to retain dissolved manganese and iron.

For example, a cartridge filter can be installed after the aeration tank. And before it, it would not be a bad idea to use a mud trap, which will retain all the large fractions.

Ionic filters

These systems are based on the use of catalytic resins and are classified as reagent methods. Depending on the required degree of purification, different types of reagents can be used.

The operating principle of such systems is based on replacing manganese and iron ions with sodium. Thus, ionic columns can easily cope with impurities dissolved in water.

Ionization

Unlike aeration systems, ionic columns require periodic replacement of the reagent. However, its properties can be partially restored using ordinary table salt. Thus, it may be enough for 3-4 years of use.

Reverse osmosis

A purification system based on reverse osmosis is considered the most effective. It allows you to remove almost all existing impurities from water. This system is based on the use of a fine-grained membrane.

As a result of the system’s operation, the water flow is divided into two parts - the clean water goes into the water supply system, and the dirty water goes into the drain. However, reverse osmosis also has disadvantages:

  • high cost of the system;
  • Cleaning too much is a bit absurd, but it's a fact. At the outlet of the installation, practically distilled water is obtained. And to use it for drinking, you will need to do additional mineralization;
  • low productivity - due to the purification technology, about 2/3 of the incoming water goes into the sewer.

To save money, it makes sense to divide the common water supply into drinking and technical. Reverse osmosis is connected only to drinking water. Another point is that the membrane is very sensitive to solid contaminants. Therefore, it is better to install a coarse filter in front of the system.

Reverse osmosis system

Cost of ready-made solutions

Depending on the performance, as well as the operating principle itself, filters for purifying water from manganese can have completely different prices:

Thus, you can purchase a filter for relatively little money. It must be remembered that the best results will only be achieved by comprehensive water purification from a well. And in order to choose the right system, you must first do a laboratory analysis of the water.

Manganese enters natural waters as a result of leaching of ferromanganese ores and other soil minerals. A significant amount comes from the decomposition of the remains of aquatic animals and plant organisms.

The maximum permissible concentration of manganese in drinking water is 0.1 mg/dm3.

Manganese is considered one of the most commonly found toxic elements in spring water, and when MPC levels are exceeded, it can cause many undesirable health effects.

If the permissible concentration of manganese in drinking water is exceeded, the liquid acquires a yellowish tint and has an unpleasant astringent taste. Drinking such water is not only unpleasant due to the bad taste, but also dangerous to health.

An increased content of manganese in drinking water threatens liver diseases, where this metal is mainly concentrated. In addition, manganese, consumed together with water, has the ability to penetrate the small intestine, bones, kidneys, internal glands, and affect the brain. As a result of the constant consumption of drinking water in which the content of this chemical element is exceeded, chronic poisoning with this metal can begin. Poisoning has either a neurological or pulmonary form. In the case of a neurological form of poisoning (when manganese penetrates the tubules of nerve cells, the passage of nerve impulses is inhibited), the patient experiences complete indifference to events occurring around him, drowsiness, loss of appetite, dizziness, and severe headaches.

Manganese poisoning is very difficult to diagnose. Symptoms of manganese poisoning are common to many diseases. Drinking water with high concentrations of manganese by pregnant women is especially dangerous. Women who drink water with a high concentration of manganese during pregnancy very often give birth to mentally handicapped children.

The concentration of iron in water is subject to noticeable seasonal fluctuations.

The maximum permissible concentration of iron in drinking water is 0.3 mg/dm3.

Exceeding the maximum permissible concentration of iron in water increases the risk of heart attacks, allergic reactions, liver and blood diseases.

It should be noted that all underground and surface water sources have different water quality. In addition, in every water source, especially surface water, the nature of the water changes over time. Thus, the maximum organic matter is usually observed during floods.

With the growth of urbanization and industrial production, chemicalization of agriculture, the anthropogenic factor has an increasing influence on the overall aquatic ecology, i.e. factor of human water use.

Therefore, there is now a great need to monitor the safety and quality of consumed water.

Chemical and toxicological studies must be carried out in accredited laboratories.

In the Federal State Budgetary Institution TsNPVRL in the chemical-toxicological department, determination of the content of iron and manganese in water (as well as a number of other elements, such as aluminum, silver, nickel, calcium, magnesium, chromium, sodium, silicon, cadmium, arsenic, lead, cobalt, nickel and etc.) is carried out by atomic emission spectrometry with inductively coupled argon plasma on a modern Optima 7300DV device.

Nowadays it is not particularly difficult to install water supply in a private house - if only there was time and financial opportunities. Many people use wells as a source of water. It’s good if you are lucky and the water in the well meets sanitary and other standards. What if it doesn’t, and it contains harmful chemicals? The same manganese is not so rare in water. And if its concentration is too high, the water must be purified. Today we will talk about how best to do this.

From this article you will learn:

    How does increased manganese in water affect the human body?

    Why is manganese dangerous in water, and what are the standards for its content?

    How can you determine manganese in water?

    What methods are used to purify water from manganese?

    What filters are used to purify water from manganese

What effect does manganese in water have on the human body?

People learned to use manganese for their own purposes a long time ago. Another naturalist from Ancient Rome, Pliny the Elder, wrote about a type of magnetic iron ore that can be used to brighten glass. Perhaps Pliny would have gone further in his research, but he died during the eruption of Vesuvius. In the 16th century, the famous alchemist Albertus Magnus named this mineral magnesia. And only at the end of the eighteenth century, the Swedish scientist Karl Schelle determined that magnesia has nothing to do with magnetic iron ore, but is a compound of an as yet unknown metal. The first to obtain metallic manganese in 1774 was Schelle’s friend, the chemist Johan Gottlieb Gann.

Manganese is a very common element, ranking fourteenth in abundance on the planet. It is literally everywhere: in the earth, in water, in plants and animals. The properties of manganese are such that it can be used in a wide variety of areas of life - from industry to medicine. Even in everyday life, the use of manganese is not uncommon.

There is very little manganese in the human body, a microscopic amount, but its importance is difficult to overestimate. For example, without manganese we would not be able to absorb vitamin B1, which is responsible for the functioning of the nervous and digestive systems of the body. Even normal heart function depends on B1, and therefore on manganese. If the amount is insufficient, the risk of developing diabetes increases. This microelement also helps the normal development of the skeletal system.

We cannot do without a certain dose of manganese in the body. And this amount has long been calculated by medical scientists:

    The daily norm for an adult is up to 5 mg;

    For a child under 15 years old – 2 mg;

    For a child up to one year – 1 mg.

However, as Hippocrates said: “Everything is medicine, and everything is poison - it’s all a matter of dose.” The same goes for manganese. A large amount of this trace element in the body will not bring anything good to a person. If the manganese content is exceeded eight times, brain functions are impaired. The most dangerous is systematic poisoning with manganese.

How manganese appears in natural waters

There are not so many safe sources of drinking water today. As a rule, any natural water has to be purified, which is what water treatment plants do. In some areas of our country, the soil is especially rich in manganese salts, and when using water from underground sources in these areas, a corresponding problem arises. Excess manganese must be removed from water to preserve human health.

Manganese is rarely found in its pure form, but is included in a large number of minerals. Some acid and ferruginous ores also contain manganese. It would seem, what does this have to do with water sources, how does manganese get into them? There are two main ways:

    Natural. Manganese is washed out of the minerals containing it by water. It can also enter the water in very significant quantities from decomposed aquatic animals and plant organisms (especially blue-green ones).

    Technogenic. This is waste from chemical plants and metallurgical plants dumped into water bodies. Some agricultural fertilizers also contain manganese, which then ends up in the water.

How much manganese is there in the water? Much depends on the area and what kind of water is meant. The least amount of it is in sea waters - about two micrograms per cubic decimeter. In rivers - from 1 to 160 mcg. But the absolute record holder here is underground water. They can contain hundreds and even thousands of micrograms per cubic decimeter. Quite often, manganese is found in water along with iron, although its concentration is lower.

The amount of manganese in water is not constant; it changes depending on the season. In winter and summer, the content of heavy metals in water bodies is higher due to stagnation of water. But in spring and autumn the situation is exactly the opposite. There are other factors that affect the level of manganese in drinking water. For example:

    Temperature;

    Amount of oxygen;

    pH (hydrogen value);

    How actively aquatic organisms absorb or, conversely, release manganese;

    Are the reservoirs connected to local lakes or rivers?

    Volume of manganese released into drains, etc.

According to World Health Organization standards, the amount of manganese in water should not exceed 0.05 milligrams per liter. Unfortunately, they are not observed everywhere. In the USA, for example, the manganese content in some places is ten times higher than the permissible level. In Russia, the established norm for drinking water is no more than 0.1 milligrams per liter. However, the same figure is also relevant for domestic water.


What are the dangers of excess manganese in water?

When there is too much manganese in water, it has a bad effect not only on human health. Household appliances and even the plumbing system, which are much more resistant to chemical influences, also suffer.

The effect of manganese on the plumbing system and household appliances:

    Due to manganese deposits, the permeability of water pipes deteriorates and their service life is reduced.

    The same applies to the heating system: manganese deposits in the pipes reduce heat transfer.

    Pipes can become completely clogged - “thanks” to manganese bacteria. Everything happens in the same way as in the case of the action of iron bacteria.

    A large amount of manganese in water has a bad effect on electrical appliances. Scale in a kettle or washing machine is often formed precisely because of this substance.

    If black spots appear on plumbing fixtures or household appliances, this may indicate that the manganese content in the water is too high.

Human health is much more fragile than household appliances. This is why you need to carefully monitor the water you use. If suddenly the water has a slightly yellowish tint and it tastes unpleasant not only on its own, but even in tea or coffee, this is a sure sign that the concentration of manganese in it is unacceptably high.

What exactly is dangerous about excess manganese in the human body? First of all, a negative effect on the nervous system. This is especially dangerous for children. According to studies, high concentrations of manganese in a child’s body can affect his intellectual abilities.

If the concentration of metal in the body is too high, general poisoning may occur. Main symptoms its as follows:

    A person's appetite decreases;

    Headache and dizziness;

    Cramps and back pain occur;

    Mood changes occur;

    The patient has a general loss of strength and apathy.

If you constantly drink water with a high concentration of manganese, then:

    The condition of the skeleton may deteriorate;

    There may be a decrease in muscle tone, and even muscle atrophy may develop;

    Allergies are possible;

    The kidneys, liver, small intestines and even the brain may be affected;

    There is a high risk of developing cancer and Parkinson's disease.

Why is high manganese content in water dangerous for the human nervous system?

Manganese is a heavy metal that tends to gradually accumulate in the body. With constant consumption of water with an excessive concentration of manganese, sooner or later the human nervous system will suffer. Here you can highlight three stages of the disease:

At the first stage, disorders of the nervous system are functional in nature. A person gets tired faster, he periodically or even constantly wants to sleep. The arms and legs weaken, and symptoms of vegetative dystonia appear. There is increased sweating and salivation. Facial muscles, on the contrary, can be weakened, which will inevitably affect facial expressions. Muscle tone also decreases, and numbness is felt in the arms or legs.

The mental activity of such a patient also changes, although this is not always noticeable to an outside observer. This is expressed in the following points:

    The area of ​​interest of such a patient becomes more limited;

    Activity also decreases;

    The ability for associative thinking is dulled;

    Memory weakens.

It is significant that the patient cannot adequately assess his condition. Therefore, focal neurological symptoms of intoxication in him are quite difficult to diagnose even for a specialist. In this case, if the cause of the disease is not identified in time (namely, a high concentration of manganese in the body), then the disease can be triggered. Then the damage may become irreversible.

At the second stage of the disease, the symptoms of toxic encephalopathy increase. Namely:

    The person becomes more and more apathetic;

    He becomes more and more sleepy;

    General weakness progresses, performance decreases;

    The mnestic-intellectual defect deepens;

    Signs of extrapyramidal insufficiency appear: slowness of movements, weakening of facial expressions, involuntary muscle contractions, etc.

In addition, the activity of the endocrine glands is disrupted, and signs of numbness in the extremities become more obvious. The second stage of the disease is very dangerous. The fact is that even if the cause of the disease is found and there is no longer contact with manganese, the process does not stop there. Moreover, it will only develop over the next few years. It will ultimately be possible to stop the disease, but it will most likely not be possible to achieve a final recovery.

The last stage of poisoning, manganese parkinsonism, is characterized by severe motor dysfunction. The patient has:

    Pronunciation is impaired;

    Speech becomes monotonous, handwriting becomes slurred;

    The face is mask-like;

    Very low physical activity;

    Spastic-paretic gait (a person spreads his legs too wide when walking, he sways from side to side);

    Foot paresis is when the foot can “drag” along the ground while walking.

In addition, involuntary excessive muscle movements occur, mainly in the legs. Sometimes, on the contrary, muscle tone decreases significantly. The patient's psyche also changes. People exposed to manganese poisoning experience apathy or, conversely, are overly complacent and even euphoric. Unreasonable laughter or crying is possible. Often a person does not understand that he is sick, or believes that his illness is not serious. The mnestic-intellectual defect is progressing. The patient has difficulty determining time, his memory deteriorates, and problems arise in both professional and social activities.

The consequences, as you can see, are very serious. That is why it is so important to determine the cause of the disease in time. And if it is a high concentration of manganese in the water, you need to take immediate action. It should be remembered: the human body receives manganese not only by eating food cooked in “bad” water. In this case, even simply brushing your teeth or washing your face with contaminated water is very dangerous.

To purify water from manganese, use

How to determine manganese in water

It is no coincidence that manganese is called the eternal companion of iron. If the water you use contains iron, manganese is also present. But not the other way around. Even when there is no iron in the water, manganese may well be present. We have already talked about the consequences of an excess of this element in the human body. Therefore, water must be purified from manganese.

How can you notice that there is a high concentration of manganese in water without doing a special chemical analysis? There are several signs to look out for:

    Water becomes cloudy and dark if manganese compounds are present in it;

    Pay attention to the smell. If it seems unusual to you, this is already an alarming sign;

    If the water is allowed to stand, a black sediment will fall to the bottom of the dish;

    When there is a lot of manganese in the water, then after long contact with it, your hands and nails will definitely turn black.

And these are not all the signs. If you boil such water, a black residue will remain on the dishes. Water with a high manganese content not only has a strange smell, but also an unpleasant astringent taste. Dark spots on plumbing fixtures, deposits in water pipes, or even complete blockage of them are also the “fault” of this element. Did you feel that the apartment became colder? It is possible that manganese deposits have appeared inside the heating system, which complicates the heat exchange process.

The presence of at least one of these signs is already a reason to think twice. In this case, you must immediately limit your consumption of water with the possible presence of manganese in it. And be sure to do an analysis by contacting a sanitary station or a private laboratory. You will receive your results in approximately 3-7 days.

How is water purified from manganese?

To begin with, specialists analyze the water for manganese concentration, and only after that choose the most suitable method of purifying it.

Manganese in earth rocks is most often found in the form of a salt, which is highly soluble in water. Therefore, in order to purify water from manganese, it is necessary to ensure that this element ceases to be soluble. This is where chemistry comes to the rescue. Divalent manganese is converted to trivalent or tetravalent manganese by oxidation. Manganese hydroxides with valency 2 and 3 are almost insoluble in water.

There are several methods for oxidizing manganese:

    With the help of strong oxidizing agents that increase the redox potential of the environment. At this value, the pH of the water is not regulated.

    Weak oxidizing agents are used while simultaneously increasing the pH value of the water.

    They increase the pH value of water using strong oxidizing agents.

Divalent manganese is converted into tetravalent manganese hydroxide and deposited on the filters. In addition, it itself turns into a catalyst, which accelerates the oxidation process of divalent manganese remaining in the water with the help of dissolved oxygen.

Methods for removing manganese from water

Manganese aeration

This method is very affordable and therefore the most common. Serious aeration of manganese is carried out, then filtration. First, free carbon dioxide is separated from water under vacuum, which increases the pH level to 8.0–8.5 units. After this, it’s the filter’s turn to work. It is used as a granular filler, for example, quartz sand.

However, this method is not suitable for all cases. It is not used if the permanganate oxidation of water is more than 9.5 mgO2/l. To use this method, the presence of divalent iron in the water is required, which, upon oxidation, turns into iron hydroxide. It, in turn, absorbs divalent manganese and oxidizes it. Another condition: compliance with a strict ratio between manganese and ferrous iron - seven to one. However, the last point can be artificially corrected by adding iron sulfate to the water.

Catalytic oxidation

Manganese tetravalent hydroxide (formed on the filter surface by the metering pump) oxidizes manganese divalent oxide. The resulting trivalent oxide is oxidized with the help of dissolved oxygen to a water-insoluble state.

Demanganation with potassium permanganate

Can be used to purify both underground and external waters. Potassium permanganate oxidizes manganese dissolved in water, turning it into an oxide, which is much less soluble in water. Manganese oxide, in turn, is a good catalyst for dissolving divalent manganese. To get rid of 1 mg of the latter, you need 1.92 mg of potassium permanganate. At this ratio, 97 percent of divalent manganese will be oxidized.

After this, the water must be filtered using a special coagulant, then additional sand filler is used. Sometimes ultrafiltration equipment is also used.

Introduction of oxidizing reagents

Various reagents are used to oxidize manganese in water. But mainly it is chlorine, its dioxide, sodium hypochlorite and ozone. It is very important to take into account the pH level of the water. If you add chlorine to water with a pH value of at least 8.0–8.5, you will have to wait about an hour and a half for a good effect. Sodium hypochlorite also acts for the same time. Often the treated water needs to be alkalized. This is done in cases where oxygen acts as an oxidizing agent and the pH of the water does not reach 7 units.

Calculations show that to convert divalent manganese into tetravalent manganese, 1.3 mg of reagent substance must be taken per mg of manganese. But this is just in theory; in practice, much more oxidizing agent is usually required.

Chlorine dioxide or ozone acts much faster when treating water - only about a quarter of an hour. True, only if the pH of the water is 6.5–7.0 units. According to stoichiometric calculations, 1 mg of divalent manganese will consume 1.35 mg of chlorine dioxide or 1.45 mg of ozone. But again, more ozone will be required than in theoretical calculations. This happens because during the ozonation process, manganese oxides decompose ozone.

In general, there are several reasons why more reagents are required than indicated in the calculations. The process of manganese oxidation in water is influenced by many factors. For example, this is the pH level of water, the presence of organic matter in it, and the duration of action of the reagents used. A lot depends on the equipment used for the process. Practice shows that potassium permanganate usually needs to be taken 1–6 times more, ozone – 1.5–5 times, and chlorine oxide may even need 1.5–10 times more.

Ion exchange

Ion exchange involves hydrogen or sodium cationization of water. To effectively remove manganese salts dissolved in water, it must be treated in two layers of ion-exchange material. For this, two resins are used: cation exchange with hydrogen ions H+ and anion exchange with hydroxyl ions OH-. They are used simultaneously and sequentially. This mixture of resins replaces water-soluble salts with hydroxide OH- and hydrogen ions H+. When these ions combine, the most common water molecules are obtained without the presence of salt in them.

At the moment, this method of removing manganese and iron impurities from water is the most promising. The main thing is to choose the right combination of ion exchange resins.

Distillation

This method is based on the conversion of water into steam and its subsequent concentration. Everyone has long known that the boiling point of water is 100 °C. But this does not mean that it will be the same for other substances. This method of purifying water from manganese is based on the difference in boiling temperatures. Pure water boils first and turns into steam. Other elements evaporate only after most of the water has boiled away. Thus, we obtain clean water, without impurities. The technology is simple and understandable to everyone, but very energy-consuming.

Filters for purifying water from manganese

In this case, choosing filters is not so easy. Here you should act according to the system. First, determine the composition of the water that needs to be purified from manganese. Secondly, identify the minimum requirements for water quality after filtration. Thirdly, when choosing a cleaning system you need to pay attention to the following points:

    To the pH level of the water;

    The amount of oxygen or carbon dioxide in water;

    Is there ammonia or hydrogen sulfide in the water?

    The characteristics of the water supply system are also important: its performance and water pressure.

After this, you can begin to select a filter material to purify water from manganese. There are several of them that are the most popular.

SUPERFEROX

SUPERFEROX filter material is designed to remove iron and manganese ions dissolved in water, as well as reduce the turbidity and color of water. The basis of the filter medium is a durable natural material “pink sand” with a catalytic film consisting of higher manganese oxides applied to its surface. The action of SUPERFEROX is based on 2 principles: sorption (due to the porous structure of the material) and catalytic oxidation. When filtering water, manganese oxides present in the catalytic film accelerate the process of oxidation of divalent iron to trivalent iron with the formation of the corresponding hydroxide. Due to the porosity of the material structure, the formation of ferric hydroxide occurs both on the surface of SUPERFEROX grains and inside its pores, which leads to an increase in dirt holding capacity and acceleration of the process of iron removal from water. The resulting iron hydroxide is capable of catalytically oxidizing divalent manganese to form practically insoluble hydroxides Mn(OH)3 and Mn(OH)4. When the filter resource is exhausted, in order to restore the properties of the filter medium, it is necessary to regenerate the installation with a reverse flow of original or purified water (more efficiently, with a water-air mixture).

Ferosoft B

The multicomponent ion exchange charge FeroSoft was created for a comprehensive solution to problems in water treatment systems. This load consists of several ion exchange resins of different granulometric compositions that make it possible to effectively remove hardness salts (Ca2+ and Mg2+), iron impurities (Fe3+ and Fe2+), manganese (Mn2+), and organic compounds from the source water. The load is designed to solve the most typical problems with drinking water, and is most suitable for use in water treatment systems of country houses and cottages.

Where to buy filters for water purification from manganese

It is difficult for an untrained person to independently choose a suitable filter for water purification. Fortunately, there are specialists for this.

Biokit employs professionals who will help you choose the best option. Moreover, there is no fundamental difference whether this is an already existing water treatment system or it is still at the design stage. The optimal decision will be based on the data provided.

Biokit also offers a wide selection of reverse osmosis systems, water filters and other equipment that can return tap water to its natural characteristics.

Our company’s specialists are ready to help you:

    Connect the filtration system yourself;

    Understand the process of selecting water filters;

    Select replacement materials;

    Troubleshoot or solve problems with the involvement of specialist installers;

    Find answers to your questions over the phone.

Trust water purification systems from Biokit - let your family be healthy!