Purification of water from iron. Methods for purifying water from iron

It is known that a person can not do without water for more than a couple of days, because all metabolic processes in the body are accompanied by her participation. Therefore it is important to think about what kind of water we use. It may contain increased amounts of chlorine, magnesium and calcium salts, manganese and iron. Each type of impurities is removed in different ways. Consider how the water is purified from iron.

Types of iron

First you need to determine what iron is contained in the water.

1. Divalent. Iron of this type dissolves well in water, so it can not be seen with the naked eye. Water has a deceptive transparency. However, if it is in contact with air for a while, then the oxidation of iron occurs and the transition to the trivalent form. Then the water gains a red tinge.

2. Trivalent. It is oxidized iron, in liquid it is found in colloid form (small particles of red color). Often in water containing ferric iron, there is also a bivalent type. In addition, the settling of red particles can be accompanied by the formation of iron bacteria, and subsequently their increase.

3. Bacterial. It is a living and dead bacteria, as well as their living and envelope products. In most cases, it accompanies the colloid gland. Outwardly it is mucous soft deposits, which can be both harmful and not. The presence of iron bacteria in the pipeline leads to ulcer corrosion of iron.

Methods for purifying water from iron

The dissolved ferrous iron can be removed by conventional methods designed to remove dissolved inorganic ions. This ion exchange, the essence of which is the substitution of special resins for the sodium ion and reverse osmosis during the reaction, its principle consists in the use of membranes that retard dissolved iron.

Another method of water purification from iron of divalent type is the chemical method. Its principle consists in catalytic oxidation, during which the chemical element passes from the dissolved state to the undissolved state. After that, the formed ferric iron settles on the filter. Systems of this kind are called filters-deferrents.

Water with an increased content of fine reddish particles is purified by ultrafiltration.

When eliminating the bacterial type of iron, chlorine or chelating agents should be used.

It should be remembered that the methods of water purification from iron have their disadvantages and advantages.

Reverse osmosis

Purification of water from iron with reverse osmosis consists in forcing it through a very thin membrane. It does not let even the smallest impurities pass. Such a result of purification is not able to guarantee any filter of water purification from iron, working by another method. That's why the reverse osmosis system is really unique.

For good operation of such a filter, it is necessary to ensure complete absence of oxygen, otherwise oxidation will occur, and ferrous iron will turn into a dispersed iron, which will subsequently accumulate on the membrane. This is not a problem, because reverse osmosis systems have good tightness.

Also this method can remove trivalent iron, if it is present in water in a small amount. The technology of reverse osmosis makes it possible to get rid of manganese, a known iron satellite.

Ionic method

This method has been used for a long time, however, zeolites and sulfonated coal were used to purify water earlier. Currently, in order to remove iron, special ion-exchange resins are used. With their help, the effectiveness of this method has become much higher. In addition to ferrous iron, the cation exchangers used eliminate calcium and magnesium ions. Also, the ionic purification method is able to remove manganese, which is so often present in water.

However, it is worthwhile to know that this method does not work if the water hardness is at a normal level. After all, the system of water purification from iron by ion exchange implies a decrease in this index. The method is used exclusively in limited pH ranges. In addition, the organic substances present in the water negatively affect the formation of bacteria on the filter.

The most difficult task here is to choose the right combination of resins correctly. Then from the iron there will be no trace, because water purification by the ionic method is currently one of the most effective.

Chemical method of water treatment

Often, an oxidative method is used to purify iron in a dissolved form. It implies the use of such oxidizing agents as potassium permanganate, chlorine, oxygen, ozone. With their help, the process of converting dissolved iron into trivalent is accelerated, and the addition of coagulants (chemicals) to the water contributes to the precipitation of particles. This principle is often used in large-scale cleaning systems.

In domestic conditions, a catalytic method is used. Purification of water from iron is accompanied by an oxidative reaction, which occurs on the surface of the filter, the properties of which significantly accelerate the oxidation process. Such systems are made on the basis of manganese dioxide, which can remove iron. To improve the result, manganese can be added to the water.

Features of filters-deferrators

If the choice fell on the water purification system based on the oxidation of iron, then a number of parameters should be taken into account:

• water temperature;
• PH;
• Oxygen content in dissolved form;
• alkalinity.

These factors can affect the quality of work. Before use, read the manufacturer's recommendations and follow them for future use. Especially it is necessary to pay attention to the speed of the direct water flow and backwashing, as well as the permissible iron content.

Common reasons for the poor efficiency of the iron removal filters include incomplete oxidation of iron, the supply of large amounts of water for purification, and a low water flow rate during backwashing. The iron content should not exceed 15 mg / l. Filters deferrilizers have a large specific gravity, which is their essential disadvantage.

Removal of trivalent iron

With a high content of colloidal iron, the most effective systems are ultrafiltration. The principle of operation of such systems is the passage of particles through a membrane grid. As a result of this process, water is purified from iron.

For ultrafiltration, special membranes with a pore size of 0.05 microns are used. The effectiveness of this method of deironing water is due to the fact that the system is able to work in different modes. Especially it is necessary to note the reverse washing of membranes, which allows to exclude the occurrence of blockages.

To achieve greater efficiency, it is better to transfer the iron to an oxidized state before cleaning.

Biological deironing method

The biological method is aimed at converting dissolved iron into an oxide form using iron bacteria. They do not pose a threat to humans, unlike their products of vital activity.

Iron bacteria show activity at an iron level of 10 to 30 mg / l, but can also develop with a harmful impurity below these indications. In order for microorganisms to function normally, it is necessary to keep the acidic medium at a low level while simultaneously supplying oxygen from the air.

At the conclusion of the biological method of deironing, the removal of the products of vital activity of iron bacteria takes place by means of adsorption, then the water is treated with bactericidal rays in order to finally purify the liquid.

Of course, this method is environmentally friendly and effective, but it has a big disadvantage: low process speed. In addition, in order for the cleaning performance to be at the proper level, it is necessary to have large-size cleaning tanks.

Purification of drinking water

At home, water is purified using the following methods:

• Defending. This is the most elementary way: water is left for several hours, during which the impurities and precipitation fall to the bottom. However, the effectiveness of this method is low, after the procedure, the liquid will boil.
• Frost. Water should be poured into a container and sent to a freezer. After the main part turns into ice, the residue must be drained: it contains impurities. Defrosting water, you need to throw away the last ice, they also contain harmful substances.
• Shungite and silicon. Minerals should be placed on the bottom of the tank, then pour water and leave at least two days. At the end of time, the water that is on top can be drained and consumed, and the "bottom" should be poured out, a sediment will be present. Shungite and silicon serve as good purifiers of liquid from harmful impurities.
• Coal. This drug will get rid of sediment and mechanical impurities. It is necessary to wrap the coal in cotton wool and pass the water through the obtained homemade filter.

Why purify water from iron?

The presence of iron in water, which has not been filtered, spoils its odor and taste. In addition, undissolved impurity particles stain the liquid in a brown tint. The constant use of water with a large amount of iron can lead to the appearance of various diseases, primarily affecting the kidneys and liver. It will also negatively affect the skin condition, allergic reactions may appear, and a sediment will accumulate in the drainage system.

In addition to causing damage to human health, the iron in the water will lead to such consequences as the appearance of yellow stains on the plumbing, the overgrown pipelines and their corrosion, a significant decrease in the quality of the products and the breakdown of equipment at the enterprises.

The optimum value of the iron content in water is 0.3-0.5 mg / l. At high rates, rust will form, and with less, turbidity will appear.

The cost of deironing water

If you run out of the tap water with an unpleasant smell and vkusom, then to cope with this problem will help clean water from iron. The price of filters, depending on the type and mode of operation, has a different cost.

The most common filter is a jug, the principle of which is based on the entry of water into the tank through the sorbent layer. The cost of such a jug varies from 200 to 2500 rubles.

Filters that assume placement under the sink, have a higher cost. Reverse osmosis systems are found on the market at a price of 5,000 rubles, and electrochemical filtration will cost about 25,000 rubles.

The cost of the product is affected by the availability of storage capacity, its volume, as well as the degree of purification.

Do not forget that the installation of an installation of water purification from iron is better to provide specialists whose services also have to be spent.