In addition to household water purification, methods and devices for which are often discussed, its industrial processing also plays an important role. Industrial water filters are used here. The methods and technology for working with liquid on these scales are similar to those used in everyday life, the difference is only in the volume of water passed through. However, there are cleaning methods that are used exclusively in industry.
From this article you will learn:
Where are industrial water filters used?
What types of industrial filters are there?
What are the features of a mechanical filter?
How does an industrial deferrization filter work?
Where are industrial filters used for water purification?
Many industrial enterprises require water with certain properties. Softening and fine cleaning are often carried out, since this has a positive effect on the quality of the products produced and competitiveness. Therefore, specialized industrial water filters are used.
Another reason why water filtration systems are constantly used in our time is that the centralized water supply system is not able to provide liquid that meets all requirements. Hard water can cause serious damage to expensive equipment in a short time, causing all processes in enterprises to stop for a long time.
There are general directions in industrial water treatment, but specific industrial filters for water purification will be specialized for each area of production. For example, it is important for one enterprise to remove iron from water, but for another it is of no use. But most of the industries use the water softening function.
All existing industrial water treatment systems can be divided into groups according to the scope of production (Table 1).
Table 1.
|
Scope of application |
Filtration system type |
|
Food industry |
Membrane cleaning; Electrodialysis; Nanofiltration; Ozone treatment; Ultraviolet disinfection |
|
Chemical plants |
Ion exchange; Mechanical cleaning; Reverse osmosis desalting; Softening |
|
Pulp and paper industry |
Ion exchange; Mechanical cleaning; Ozone treatment |
|
Glass industry |
Ion exchange; Reverse osmosis; Mechanical filtration |
|
Industrial waste |
Electrodialysis; Aerobic oxidation; Ozone treatment; Ion exchange; Reverse osmosis |
|
Agriculture |
Mechanical filtration; Aerobic oxidation; Softening |
|
Energy |
Ion exchange; Mechanical filtration; Softening |
Note that when focusing on a certain type of industrial water filter, bacteriological, physical or chemical treatment is not abandoned. In addition, modern quality standards for raw materials require the use of exclusively environmentally friendly products in all areas: production, energy, and agricultural activities. The scope of use determines what industrial water filters are more focused on, for example, removing harmful substances and microorganisms (food production, wastewater treatment), desalting (energy, petrochemicals, chemistry), and combating biological fouling of equipment (agriculture).
Stages of industrial water treatment
Typically, gravel filters for mechanical three-stage water purification, industrial and multimedia loading are used. Only by combining all these characteristics can the final product be of the required quality.
- Mechanical cleaning.
Processing is carried out by three types of filter mass of different dispersion. The top layer includes a large fraction, large elements settle here, on average, respectively, medium ones, and the smallest particles remain in the last layer, including sand 20 microns in size. With this method, the main contaminants are eliminated, and the industrial water filter is able to function properly for a long time without rinsing. This is the main advantage of a three-layer mechanical model in contrast to a single-layer one.
- Deferrization.
After the mechanical stage, bactericidal industrial water filters and iron removers are used. There can be one water filter or a whole set. The organoleptic properties of water improve, which directly depend on its chemical composition.
Let's talk about iron removers. All of them are aimed at the formation of insoluble substances from iron compounds to form light sludge. This sediment is removed mechanically. Here chemicals, that is, reagents, are used. They react with compounds, causing iron to change from divalent to trivalent form.
Instead of reagents, a backfill of green manganese sand can be used; it also perfectly performs the function of deferrization. To do this, install a pump that dispenses the regenerator (potassium permanganate) into the liquid.
- Sterilization.
The third step in water treatment is sterilization. The fact is that water contains many bacteria and viruses that cannot be eliminated by mechanical cleaning alone. Their vital activity causes the formation of a layer of sludge on the equipment. In the food industry, this entails a risk of disease.
Sterilizing industrial water filters work with ultraviolet light. In an hour they are able to cope with nine cubic meters of water. In this case, unlike treatment with chlorine, no additional substances enter the water, which means the taste and color of the final liquid do not deteriorate. Such filters remove almost all bacteria and viruses; they are necessarily installed in the food, perfume, and pharmaceutical industries.
The system here is simple; it includes an ultraviolet lamp and a cuvette for water. In this cuvette, the liquid is exposed to irradiation for some time.
- Water softening.
Ion exchange units reduce hardness. Purification devices in factories determine the volume of water; it can be changed using the control unit.
To select an industrial filter for water purification, it is important to clarify the performance, power of the equipment, amount of energy consumed, operating conditions, requirements for physical, chemical, and biological compositions.
Industrial water filter
Industrial filters for coarse water purification are necessary where the penetration of large particles into equipment becomes critical. Let's say the water seems perfectly clean, its chemical composition is close to excellent, but this does not mean that there is no need to use a coarse filter. Small particles of sand and other elements can be really dangerous for various devices.
Rough cleaning is the first stage of processing. The fact is that when the flow has passed through the well filters, there are still quite a lot of solid particles remaining in it, due to which the water cannot go to work. Therefore, preliminary water treatment is mandatory, even if there are good industrial filters for well water.
Rough processing guarantees a simple thing - the removal of heterogeneous solid inclusions. This group includes sand and gravel with a size of 15 microns. Particles visible to the naked eye remain in the filters, which is why the method is called “mechanical” rather than rough cleaning. The technology is similar to sifting a water stream through a sieve. Filtration equipment is installed after the pressure tank in the supply pipeline section.
If we talk about the number of devices, then efficiency is not always associated with the presence of 2-5 absolutely identical filters. In such a situation, the pressure only drops and the level of resistance in the line rises, and this entails an increase in the load on the pump. If there is a need to install any other devices for this stage of processing, it is recommended to select industrial water filters of different sizes and install a high-power pump.
Remember! Primary filtration devices can continue to be effective in conditions of sudden pressure changes, temperature changes and are excellent at removing large diameter contaminants.
This option is simpler than others, but this industrial flow filter for coarse water purification remains one of the best. It is mounted at the direct inlet of the flow and captures elements up to 300 microns in size. According to their design, mud collectors are:
horizontal;
vertical;
Y-shaped.
The list of their advantages includes: purification up to 90%, the ability to operate at temperatures up to +150 ° C and pressure up to 6 MPa, long service life. However, let's say that using the device requires monitoring hydraulic resistance. The device body can be equipped with a removable bottom, a side hatch and have the ability to bleed air masses and drain the liquid flow.
Based on the connection principle, mud traps are divided into welded and flanged. You will be pleased to know that such industrial water filters can be used without registration with regulatory authorities, and they are also not required to be equipped (in addition to the mesh) with magnetic traps for separating metal particles.
Coarse mesh filters
This model has a mesh fabric with small cells - up to 20–500 microns. When choosing a design, look at the photo to determine the technological characteristics. Thus, there are industrial water filters with an automatic backwash function. That is, there is no need to disassemble the system to remove residual dirt.
Typically, mesh models have a pressure control valve installed at the outlet. An undeniable advantage here is the function of protecting the internal pipeline and household appliances from water hammer, sudden pressure changes, and debris. And the combination of a coarse filter with a pressure gauge will make it possible to regulate the output pressure of the liquid flow.
Small size, durability, practicality, ease of use - all these are the advantages of such equipment. However, it must be taken into account that industrial water filters with a backwash function are only suitable for installation in a system equipped with a drainage pipe, where the flow of liquid with impurities can go.
Coarse disc filters
These industrial water filters include a number of elements (depending on the required performance and the initial state of the liquid). They are installed in individual pressure housings and combined with collectors: inlet, outlet, drainage.
The filter element looks like a package of compressed (in working condition) polymer disks with a hole inside and notches on both sides (the depth and width of the latter affect the level of cleaning).
During processing, the liquid enters the filter element, large contaminants end up on its outer part, and smaller ones settle between the discs.
That is, this industrial water filter provides surface (outside) and volumetric (in discs) liquid purification. This feature allows you to achieve greater dirt holding capacity when compared with the previously described model.
The cleaning elements are washed one by one for 10–30 seconds with a reverse flow of treated water. Such a short period of time for backwashing allows you to achieve incredibly low fluid consumption for “own needs” (from 0.1 to 1%).
This feature is associated with the simultaneous presence of such factors:
washing occurs in the opposite direction relative to the worker;
the process is carried out with clean water (water is taken from other operating parts of the system);
during flushing, the element disks unclench, releasing accumulated particles;
in this state they rotate and touch each other, due to which clay and silty deposits are well removed.
It is important that water continues to flow to consumers during flushing. This cleaning of industrial water filters occurs automatically, after a selected period of time, or when a specified pressure difference is reached between the inlet and outlet of the system.
The service life of filter parts is not regulated.
High speed cleaning structures
This type of industrial mainline filters for water purification is usually used for the primary treatment of liquids on a production scale. This model looks like a column-container with filter material inside. It is important that the design is characterized by a very high throughput and retains particles of different fractions ranging in size from 30 microns.
Despite the fact that these devices are recognized as the best for this type of filtration, they also have disadvantages:
big sizes;
the need to install them only in rooms with a constant warm temperature;
the need for a drainage water supply to ensure regeneration processes, which will have to be additionally prepared.
Grain filters
For rough mechanical cleaning, industrial pour-type water filters can be used. Here, contaminated water passes through layers of various granular and porous materials. A single-layer or multi-layer processing scheme can be selected. These systems are excellent when it comes to removing particles with a rating greater than 5 microns.
All their preparation consists of setting hydraulic modes, frequency, and time of loosening washing. Regeneration usually does not require chemical reagents and occurs quickly. The frequency and time of cleaning the device is calculated in accordance with the characteristics of the water entering it and the characteristics of the filter load.
Industrial filter for purifying water from iron
At home, you can remove iron from water using a deferrization filter, but in production you have to use a water deferrization station.
It frees water from excessive levels of iron, hydrogen sulfide, manganese and other elements. This occurs through the oxidation of iron from divalent with an oxidation state of +2 to trivalent with an oxidation state of +3. Thus, iron is transferred from a dissolved form to an insoluble one, the latter will precipitate and is retained by the special filter load of this industrial water filter.
The amount of iron in the treated liquid cannot be more than 0.3 mg/l, according to the requirements of SanPin 2.1.4.1074-01 “Drinking water”.
Today, several technologies have been developed to free water from iron. The choice of one of the options depends on where it will work: in industry or in housing and communal services.
A typical station kit includes the following elements:
aerator tank with separator and compressor;
cleaning filter;
pump equipment;
automatic control;
pipes and shut-off valves.
Most often they prefer automatic control of a station with a single control unit. But there are industrial water filters that are manually operated. A fully automated station is capable of operating around the clock without the need for an operator.
When configuring the station, it is important to consider the following characteristics:
average daily and hourly water consumption;
water consumption mode – peak loads and required volume;
the presence of sewerage and the possibility of connecting an industrial water filter to it;
indicators of pumping equipment.
These stations remove iron in two ways - reagent and non-reagent.
Oxidation with oxygen (non-pressure aeration and pressure)
There are many options for the oxidation of iron from degree +2 to degree +3: lime, chlorine (ClO 2), ozone (O 3), potassium permanganate (KMnO 4). But based on many years of experience of our company Biokit with iron removal systems, we can say that the most economically effective, environmentally friendly and frequently used method of iron oxidation is iron removal using gravity aeration.
Aeration enriches the water with dissolved oxygen, which is required to convert iron into an insoluble form, without the need for chemical reagents.
The essence of the technique is that the oxidation of iron and the collection of undissolved sediment are carried out in different modules. Therefore, with intensive mixing of water with air oxygen in the ejection system, complete oxidation of iron occurs. The collection of oxidized material is carried out on sediment filters with inert loading with a low specific gravity and a developed surface.
Air perfectly oxidizes both iron and hydrogen sulfide. Used in industrial water filter systems, it quickly converts iron molecules with an oxidation state of +2 into an oxidation state of +3, and converts hydrogen sulfide into elemental sulfur - which is also easy to remove with a filter.
It is important that such a strong and fast oxidizing agent as oxygen works faster than chlorine.
After many years of working with various objects that required the removal of iron from well water, HYDROCITY specialists created and implemented an original method for purifying water from iron using gravity aeration. This treatment is most widely used in industry, thermal power engineering and housing and communal services.
Oxidation with sodium hypochlorite
In addition, the oxidation of Fe2+ to Fe3+ can be carried out by sodium hypochlorite. This option is used by water utilities instead of technology based on liquefied chlorine. Working with sodium hypochlorite entails installing a dosing pump and a device for introducing a solution of this substance into the water stream.
The liquid in such an industrial water filter enters a contact container, where it settles; in some cases, a coagulant can be introduced into it, which then makes it easier to retain impurities on the filter loading. Next, the pumps supply water to pressure filters with granular loading such as sand or anthracite mixed with sand loading. That is, this treatment does not produce toxic waste.
Personnel must constantly monitor the functioning of the pump, its regular washing (it often becomes clogged due to hypochlorite crystallization), and proper handling of hypochlorite. The fact is that this unstable substance quickly decomposes, and the concentration can decrease under the influence of a number of factors.
To reduce operating costs when using sodium hypochlorite at water utilities during iron removal and during primary, repeated disinfection, it is better to install a station for the production of this substance from table salt using electrolysis.
Oxidation with Greensand
This is an old method used in industrial water filters. The active substance in Greensand is glauconite. Otherwise it is called green clay, that is, it is a mineral that contains iron and has ionic exchange properties. Glauconite is often found mixed with other materials and looks like small granules, hence the name "Greensand". It is mined, washed, sieved and treated with chemicals to produce a durable greenish-black product that can adsorb (collect in compressed form on the surface) iron and manganese.
The liquid passes through an industrial water filter, soluble iron and manganese are drawn out of it, and a reaction occurs that results in insoluble substances. These components will accumulate in the Greensand filter and be removed by backwashing. It is important to carry out such filter cleaning on a regular basis, twice a week, or based on the manufacturer’s recommendations.
In addition, “Greensand” requires regeneration by washing with a permanganate solution. The frequency of this procedure will vary depending on the level of iron, manganese, oxygen in the water and the size of the filter.
Most of these filters are designed to treat water with iron concentrations up to 10 mg/l. The acidity (pH) of the water affects filtration. When the pH value is less than 6.8, Greensand may not adequately filter the elements. The pH may rise above 7.0 after passing water through the calcite.
Regular backwashing is necessary for an industrial water filter to function effectively, and this process requires a flow rate 3-4 times higher than that of a household filter. If the system is unable to provide such performance, filter performance will decrease and further problems will arise.
This method is considered one of the oldest; today such water treatment options are used in very rare cases. Although the method can remove sufficiently high concentrations of dissolved iron (up to 10 mg/l), Greensand requires regular reconstitution with potassium permanganate solution and large volumes of liquid during backwash.
Ozonation
Ozone is a gas, a compound that contains three oxygen atoms - the O 3 molecule. The natural element oxygen is presented in the form of two atoms - O 2. When energy is used to break the O 2 bond, the individual atoms form O 1 . They combine with O 2 molecules to form ozone O 3 .
In the ozonation process, ozone is added to water to provide disinfection and improve certain properties of the liquid, such as color and odor. This procedure does not leave chemicals in the water and has been used for treatment since 1906, actively spreading throughout the world.
Note that ozone gradually turns into oxygen. The rate of conversion is affected by temperature, pH and water quality. For this reason, the production and implementation of ozone must occur sequentially. The instability of the gas is explained by a weak bond with the third oxygen atom and its ability to provoke an oxidation reaction with any oxidizable substance.
Ozone is recognized as the most powerful oxidizing agent, harmlessly used as a strong disinfectant. Gall organisms are the most resistant to all disinfectants because they have protective shells, but they are also destroyed along with bacteria and viruses during water treatment with ozone.
When oxidation is complete, the iron needs to be filtered out. This happens through clarification industrial water filters, most often vertical. Illiterate or weak filtration can negate the entire procedure.
Iron removal stations can be equipped, for example, with industrial drinking water filters in various anti-corrosion designs:
metal cases;
stainless steel housings.
Devices with two and three cameras can improve performance. They are equipped with side and top hatches for monitoring and loading of filtrate.
There are many companies on the Russian market that develop water treatment systems. It is quite difficult to choose one or another type of filter for water purification on your own, without the help of a professional. And even more so, you should not try to install a water treatment system yourself, even if you have read several articles on the Internet and it seems to you that you have figured it out.
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