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Removal of iron from the water - one of the most difficult tasks in water treatment. The reason is that iron exists in nature in various forms and in various chemical compounds. A universal method of water purification from iron does not exist. Success depends on the practical experience of the person establishing the equipment and the quality of the equipment. It is clear that there is a certain contradiction between desires and capabilities of the parties. The consumer wants to get clean water at minimal cost, and water treatment company wants to sell its equipment is not at the lowest price. It is also clear that incompetent in matters of consumer water purification is more vulnerable side. In this article we will try to give the consumer the specific recommendations that he did not pay the money for the equipment, which subsequently cease to purify water.


First of all, let us consider briefly the basic methods of removing iron.

Ion exchange.

Ion exchange is used mainly for water softening. Although it is theoretically capable of removing the ion exchange high concentration of dissolved iron in practice this is impossible. The reason is the presence of dissolved oxygen in the water. In the presence of oxygen of the dissolved iron is oxidized and precipitating, envelops balls ion-exchange resin, reducing its validity. Presence of water-soluble organic substances, including organic iron, exacerbates the problem. Therefore, small concentrations of iron (up to 2 mg / l) it is advisable to remove the water together with a softening. At higher iron and kontsentatsiyah when there is no need to soften the water to be used standalone iron removers using oxidation method.


Catalytic oxidation.
The essence of the method is that the reaction of iron oxidation occurs on the surface of the granules with a special filter medium having the properties of the catalyst. Oxidized iron is precipitated and washed periodically to drain during the backwash. As the catalyst used filter media based on manganese dioxide. Widely used filter media Birmi Greensand.
The advantage of synthetic filter media Birm is that to restore its catalytic properties do not need a special recovery solution (sufficient backwash water). Disadvantages Birm material are: low working range of pH values (at least 6.8) in the absence of the need serevodoroda water and organics, and conversely, the presence of oxygen in a proportion of not less than 15% of the dissolved iron. Because of the latter condition Birm advisable to use in conjunction with pre-aeration. The chlorine content in the water must not exceed 0.5 mg / liter.


Greensand ("green sand") is a processed natural mineral glauconite. Greensand effectively removes water from iron, manganese and hydrogen sulphide. Oxidative capacity Greensand restored (regenerated) with potassium permanganate ("potassium permanganate"). This may apply periodic or continuous regeneration.
In batch regeneratsiiobrabotka filter medium saturated with potassium permanganate produced in time intervals calculated in the downward direction, and the excess of potassium permanganate, together with the precipitated iron oxidation in the opposite direction to drain water washable (reverse washing). The disadvantage is the high consumption of potassium permanganate and its failure if used for wastewater treatment bioseptiki since potassium permanganate kills microorganisms and displays a septic tank failure.
With continuous dosing of potassium permanganate is used in small amounts and hardly washed off drainage. However, the disadvantage of this method is that when the composition of water, such seasonal, can "slip" in purified water, or iron, or an excess of unreacted permanganate.
Filter media Filox, Pyrolox et al. Work on the same principle as the Greensand, so treat them does not make sense.


Air oxidation (aeration)

Aeration systems are designed for the oxygenation of air, oxidizing dissolved iron to iron removal filters, and for degassing of dissolved gases (hydrogen sulfide, ammonia, methane, and so on. D.). Aeration is carried out in a forced air tank filled with water to be cleaned (also known as aeration column) using a compressor. Allocated from the water gases and excess air output from the air valve. The advantages of this method of water treatment include the lack of chemicals, ease of maintenance, lack of supplies. However, periodic maintenance (about once a year) it is necessary to clean up some elements of aeration system from deposits of iron.
There are pressure and non-pressure aeration systems. In the non-pressure tank systems use a non-standard high-volume and required an additional pump to lift water. Such a system is less convenient to install and use and is not considered here.
Pressure aeration system consists of aeration columns filled with water (tank), air compressor, water flow sensor and the air valve. Iron oxidation starts in the aeration column. Iron oxides, followed by delayed sediment filter.
Note. The method of the oxygenation using air injector (tube Venturi) is not very effective and almost fell out of use.


Reagent water iron removal (dosing).
Reagent water purification method based on iron from iron oxidation with strong oxidizing agents. For supplying water into the oxidant are special metering pumps. This method of water purification is used in high concentrations of iron, manganese, serovodoroda.Dostoinstvomdannoy technology is also possible to remove a significant portion of water from organics and simultaneously disinfecting the water. Drawback - the need to replenish the chemical reagent (usually sodium hypochlorite) and its toxicity, requiring very accurate dosing or the use of additional carbon filter. To improve combined use possibly dosing and aeration.


Often the client on the issue of water analysis says: "I like all the iron." Unfortunately, the hardware "like everyone else" does not happen. Even in the neighboring wells, water may vary on the composition of iron and other organic components. Therefore, water treatment must always begin with an analysis. Select the best method to remove iron without water analysis impossible.
The method of water purification from iron offers, of course, water treatment company. But the choice has to do to someone who pays. Practical recommendations for each method can help the consumer with a choice.


Ion exchange.
When hard water and a small amount of iron (up to 2 mg / liter) can be dispensed one softener. At higher iron content there is a risk clog softener. At an iron content of more than 3 mg / liter should be prepared for frequent replacement of the ion exchange resin or to set obezzhelezivateli softener.


Catalytic oxidation
Filter Birmdeshev backfilling and convenient to use, since it does not need chemicals for regeneration, however, has several limitations. Conclusion: watch water analysis and determine us to be Birm-ohm or without him. It should be noted that the percentage of oxygen in water conventional laboratory analysis is not determined. But it is possible that the water is sufficiently oxygenated. The solution is simple: if there is no protivoplokazany above, put the filter and see the result. If there is no result, put a filter in front of the aerator. At a high iron content (over 5 - 6 mg / liter) of the aerator installation is required. It should be noted that the restriction on the acid-base balance (pH) can be eliminated. But you need to install an optional filter, adjustment of pH.
Filter Greensand- stronger catalyst than Birm, has such a number of restrictions, but needs a regeneration solution of potassium permanganate. Periodic regeneration is not suitable where applicable biological wastewater treatment. Constant regeneration of effluents friendly, but can contaminate clean water. The conclusion is that if you have a biological wastewater treatment, it would be preferable aeration.


Pressure aeration
Importance is the contact time of the dissolved iron with oxygen, so the aerator tank (aeration columns) should be small. In practice, it is assumed that the aerator tank should be equal to or greater than the filter tank. About the tank will not speak, because all manufacturers quality tanks roughly equal. But the quality of the other elements is essential. The compressor must be oil-free, small-sized, lightweight, as mounted on a wall above the tank, and low noise, as placed in a room and not in the wood. "Bicycle" is no need to invent. There compressors specifically designed for water aeration. Most of the leading firms use aeration compressors American production that meet all the above requirements. Air valve dozhen also be of high quality, otherwise the system will not work properly. The valves can be mechanical or electronic. Among unrivaled mechanical valves Israeli production. Good electronic valves produce the Americans. To turn on the compressor can be used flow sensor starts the pump. However, the pump is not normally the responsibility of the water treatment company, it would be preferable to establish an autonomous sensor, although it is slightly increases the cost of the system. Good flow sensors produce Germans and Americans.
After the water enters the aerator filter, wherein the oxidized iron delayed and washed into drain periodically backwashing. There is a false belief that a high concentration of iron is necessary to put a larger filter, the filter contains a large amount of filling. In fact, the installation of a large filter can create big problems. Firstly, for backwashing the filter medium is required water flow is several times the intesivnost filtering (for heavy fillings in 4 - 5 times). If the pump capacity is insufficient for high-quality wash the filter, the filter becomes clogged with iron and gradually cease to purify water. Second, the rate of flow of water when flushing a large filter may be higher than the absorbing capabilities of the drainage system of a house or cottage. Third, if the amount of water consumption would be too small for the filter, the water can create a channel in the filter and filling out of untreated filter. The solution is to install two small filters in parallel, instead of one big one. Such filters are washed in turn, consume less water for backwashing. This is especially true for electronic filters, since they usually have one filter column (Kinetico filters are set to double and parallel operation of the filter columns). Installation of two parallel filters solves another important problem. Filter with a single filter column is usually configured on the night washing. At high concentrations of iron filter may be clogged before the time comes to washing. This, too, will eventually lead to the complete contamination of the filter. In parallel operation of two filters can be programmed more frequent washing. One at a time by washing the filters columns only decreases the time (about 15 - 20 minutes) the throughput capacity of the system, but the system will always return the purified water. All of the above true for catalytic obezzhelezivateli with severe backfilling (Greensand, Pyrolox et al.).
It is quite clear that the quality of water treatment is directly dependent on the ability to fall asleep in the cleaning tank filter media. Please be aware that often used in Latvia quartz sand in its pure form is not suitable for modern automatic water treatment systems. Because of the heterogeneous structure of sand filters in it only a thin top layer. Therefore, requires frequent, but because of the large proportion of sand and intensive backwashing. Filter, especially if it is a filter with a filter column, such a task is often daunting, the filter becomes clogged gradually oxidized iron and ceases to purify water. The advantage of sand in cheapness. But this cheap can be expensive, often resulting in the loss of money. The application of sand is permissible in combined fillings (usually anthracite - sand - garnet - gravel).
We indicate the main filter media, which are commonly used for filters in the aeration system, in order of decreasing purity filtration: Macrolite, Filter AG, Birm, combined backfilling. The highest degree of purification at Macrolite (5 microns). This filter media was created specifically for udalegniya oxidized iron. At equal purity filter (20 - 40 microns) Filter AG has better capacity than Birm, but Birm advantage that it is both a catalyst capable of further oxidizedup iron in the filter. Filtering quality combined backfill slightly worse and it is heavier, and therefore requires intensive backwash.
Based on the above, before buying should find out what is supposed to set the compressor - a special aeration or purchased on the occasion at the flea market. It should be said that the compressor with a belt drive (there are) suitable for water aeration as well as wagon wheel fits the modern car. The same problem applies to the air valve and the flow sensor. The manufacturer usually leaves its markings on the product. If it is not clear that it is better not to put on the aerator. It is necessary to find out what the filter filling. If quartz sand, it is suitable for garden paths, but not for the aeration system. Received acceptable answers to these questions, you can make a choice, taking into account that low-quality equipment can result in loss of money.


Reagent water iron removal (dosing)
Dosed reagent injection is performed in the water before the filter or directly into the filter. The filter medium is a strong catalyst. To enhance the oxidation process can be carried out pre-aeration. Suitable dosing with large volumes of purified water and a high concentration of iron, particularly if accompanied by dissolved iron "bouquet" of organics. Say what specifically should be seized to filling in the filter is impossible, since the exact composition of organics conventional laboratory analysis is not defined. But be aware that when used as a reagent sodium hypochlorite should not be used Birm, because he is afraid of chlorine. Often high organics removed by "spear." If there is no result try another filling or other reagent. Remains of chlorine and organics can get out of a charcoal filter. Carbon filter all good, but requires frequent changes of coal (at least once a year, but the best time in half a year) because supersaturated carbon filter itself becomes a source of water pollution.
For dosing is essential quality of a metering pump. The best in the European market (it is possible that in the world) are dispensers companies BWT and ProMinent (Germany). Dispensers are also made in Italy. They are cheaper, but inferior to the German dosing accuracy and reliability.
Please be aware that the combination of iron and organic matter is the most difficult one for water purification. At very high organics best option may be drilling deeper wells.

Summarizing, we can say that for the successful removal of iron, two factors are critical: first, the correct method chosen, and secondly, good equipment, ensure the quality of water treatment, and a sufficiently long period of operation of the system.



The warranty on the system filters and KINETICO TWO YEARS.

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