The water that comes from the central water supply or well contains impurities that are dangerous to household appliances and health.
To protect your home or apartment, use water filters.
From the article you will learn what filters there are and which ones are needed for an apartment or house when supplying water from a well or a central water supply.
Types of water filters
To filter water, it is passed through a filter element, which traps impurities and allows clean water to pass through. These elements are created from cardboard, nylon or lavsan, cotton, flax, activated carbon and other substances.
Filters are distinguished by the type of filter element:
- with removable cartridge;
- with backfilling of purified sand;
- with membrane filtration;
- with metal or plastic mesh;
- ozone
Filters are distinguished by purpose:
- cleaning from mechanical contamination;
- reduction of water turbidity;
- purification from dissolved heavy metals;
- reduction of water hardness;
- protection against bacteria;
- changing the properties of impurities.
Filters are distinguished by the method of water supply:
- passive
- with forced supply as part of filter stations.
Coarse filters
The task of coarse filters (FGO) is to protect water consumers from mechanical impurities - chips, sand, organic sediments, rust. Sometimes FGOs are called “mechanical filters”. In such filters, water is purified using cardboard and nylon cartridges, metal or plastic meshes, and a layer of sand. Depending on the model of the replacement cartridge or filter element, such filters trap contaminants larger than 100-400 micrometers. Sometimes they are called water pre-filters.
The use of FGO extends the service life of fine filters. Reverse osmosis devices and ozonizers improve the operation of settling tanks. They do not purify water from smaller impurities, do not remove heavy metals, foreign odors and tastes, and do not reduce turbidity.
The sand filter element is cleaned of dirt by washing. To do this, water is supplied in the opposite direction at a speed 2-3 higher than the water supply speed in normal mode. The rinsing water and the dirt raised by it are drained into the sewer.
The metal (plastic) mesh filter element is cleaned by unscrewing the drain plug and pouring out what the filter has caught. After this, it is washed in the same way as a sand filter.
Change replaceable cartridges made of cardboard or nylon if you suspect a deterioration in the water supply. Changing a cartridge will cost less than replacing or repairing fine filters.
Fine filters
Fine filters (FPO) remove mechanical and other impurities from water, the size of which exceeds 5-50 micrometers, depending on the filter model. The water in them is purified with replaceable cartridges made of cardboard, nylon, lavsan and other materials. Adsorption filters use activated carbon or sorbents such as “superferox” or “pinkferox”. Such filters reduce water turbidity and partially remove foreign odors and tastes.
Externally, FTO does not differ from FGO, because the housings are the same, the only difference is in the permeability of the filter element. If the filter is installed in an apartment that supplies chlorinated water, then additional filtration is not necessary. Chlorine dissolved in water kills pathogenic bacteria, and PTO reduces turbidity and purifies water from small impurities.
To clean sandy PTFs, they are washed. Replacement cartridges are changed upon reaching the resource specified in the passport. It is advisable to change or wash the FTO at the same time as the FGO, even if it has purified only half of the volume of water indicated in the passport. You can see dirt on the FTO cartridge only when it has worked 3-4 times longer than necessary and filters water much worse.
Fine filters do not remove salts, heavy metals and bacteria from water, and do not change the composition of the water. For such cleaning, use ozonizers, sedimentation tanks and reverse osmosis devices.
Final filters
Such filters include reverse osmosis units, ozonizers, and ultraviolet purification devices. These filters finally purify the water, after which it is safe to drink and does not require boiling. Final cleaning filters are technically complex devices that perform several operations and consist of several blocks (depending on the specific model).
The performance of such devices is sufficient to provide drinking water, but not enough to purify bathing water, so they are installed in the kitchen, as close to the taps as possible (for example, under the sink).
Reverse osmosis filters
The basis of these filters is a water-permeable membrane that retains any substances whose molecules are larger than water molecules. For the filter to operate effectively, water is supplied under pressure of 2-7 atmospheres (bar) using an electric pump. Operations in the pump are fully automated; the operation of the entire system is ensured by water pressure sensors and a microcontroller. The water that has passed through the filter is pumped into a storage tank or accumulator.
Reverse osmosis filters (ROF) remove all bacteria and salts from water, turning the water into distilled water. Frequent use of such water for drinking will lead to leaching of salts from the body, weakening of bones and disruption of internal organs, so this water is used for cooking and washing dishes. To avoid leaching salts from the body, drink not only water every day, but also various juices, fruit drinks and other drinks.
FOO is installed after the fine water filter. Supplying untreated water to the installation will reduce the life of the membrane tenfold and damage the device.
Ozone filters
In ozone filters, ozone is supplied to the water, which oxidizes organic impurities (including bacteria) and metals that have entered the water, which leads to their precipitation. It does not purify water from large mechanical contaminants, so it is installed after FGO and FTO. Connecting the filter directly to the water supply will reduce the service life of the FTO by tens of times.
The compressor pumps air from the room into a container, where an electrical discharge converts oxygen into ozone, from where it is supplied to a chamber with water. After some time (depending on the model), oxidation turns organics and metals into flakes that precipitate. The remaining inclusions are caught by a fine filter.
The use of activated carbon in PTF purifies water from petroleum products and heavy metals. When purchasing an ozone water filter, ask what the mechanical filter of this device is made of. If the FTO is cardboard, nylon, or lavsan, then it will not protect water from oil products and heavy metal salts. If the FTO is coal, then the water is reliably protected.
To find out what indicators to choose filters for, have your water analyzed. If you take water from a well or borehole and the composition of the water complies with the requirements of SanPiN 2.1.4.1074-01, install FGO before the pumping station and FTO after it. If a well or well has been operating without disinfection for more than five years and it is impossible to carry out aseptic treatment, use ozone filters or reverse osmosis units.
If you live in an apartment with a centralized water supply, use reverse osmosis units or ozone filters. The wear and tear of water networks in Russia is more than 50 percent, so there is a high probability of pipes breaking and groundwater or fecal water getting into the water. Install two FGOs with different degrees of purification, the first with filtration of particles larger than 200-300 micrometers (0.2-0.3 mm), the second 20-100 micrometers. This will protect the final filter from damage and extend its service life.
Purifying your water will keep you and your family healthy. Select a filter for contaminants that are present in the water and worsen its characteristics. Do not neglect coarse and fine filters; the price of replacement cartridges for them is hundreds of times cheaper than the cost of final filters. Do not skimp on water treatment, because health is more expensive.
Liquid flowing in a centralized water supply can only very conditionally be considered suitable for use for technical purposes - for laundry, washing dishes, etc. With a very big stretch, it can be used for cooking, but you can’t drink it without boiling it at all. To bring it to normal, it is necessary to use different types of filters to purify water. There are inexpensive installations, but they usually have low productivity and average cleaning quality, and there are expensive systems that can give ideal results.
The situation is no better with water supply from a well or borehole. There is still a high probability of bacterial infection, so the cleansing should be even better. In general, you need to take the sample for analysis, and then, based on the results, select the required types of filters for water purification. In private homes, this is usually a multi-stage system, which results in drinking-quality water.
Cleansing from mechanical impurities
The water that flows in our water supply contains grains of sand, fragments of rust, metal, windings, etc. These impurities are called mechanical. Their presence has a bad effect on the durability of shut-off valves (taps, valves, etc.) and household appliances. That’s why in apartments and private houses they install filters at the entrance to remove them. There are few types of filters for purifying water from mechanical impurities. This is with mesh and discs as filter elements.
The filter element in mechanical filters is a mesh. Based on cell size, these filters are divided into coarse (300–500 microns) and fine cleaning devices (larger than 100 microns). They can stand in a cascade - first for coarse cleaning (mud collector), then for fine cleaning. Often a coarse filter is placed at the entrance to the pipeline, and devices with a finer mesh are placed in front of the household appliance, since different equipment may require different degrees of water purification.
Depending on the orientation of the flask in which the filter element is installed, they can be straight or oblique. Oblique ones create less hydraulic resistance, which is why they are most often installed. When installing, you must observe the direction of flow, it is indicated on the body by an arrow.
Mechanical filter
There are two types of mechanical filters - with and without auto-rinsing. Devices without auto-flushing are small in size; their inlet/outlet diameters are selected according to the size of the pipe in which they are installed. The case material is stainless steel or brass, threaded connections are different (select external or internal threads as needed). The cost of this type of mechanical filters is low - around hundreds of rubles, although branded ones can cost much more.
Mechanical filters without backwashing: straight and oblique
Since the grids become clogged and need to be cleaned periodically, the lower part of the flask is removable. If necessary, unscrew it, remove it and wash the mesh, then return everything back (all work is carried out by first turning off the water).
Mesh with automatic flushing
A mechanical filter with auto-washing (self-washing) has a pipe and a tap in the lower part of the flask with a filter element. The pipe is led into the sewer using a hose or piece of pipe. If you need to rinse such a filter, simply open the tap. Water under pressure washes the contents into the sewer, the tap closes, and you can continue using it.
This type of mechanical water filter often contains a pressure gauge. It determines whether the mesh is clogged or not. The pressure has dropped - it's time to clean the filter. If the flask of the device is transparent, there may not be a pressure gauge - you can determine it by the appearance of the mesh or the walls of the flask. In this segment, oblique water filters are rare, but they do exist.
A pressure reducing valve can be built into the housing to neutralize pressure differences. There are models with the ability to install an automatic flushing unit.
Tying this type of mechanical filters is a little more complicated - it requires an outlet to the sewer, but there are also models with different types of threads so that you can use as few adapters as possible.
Connection types
Mechanical cleaning filters can be either coupling or flanged. Flanged ones are usually main equipment for water pipelines with high pressure and diameters. Can be used to install water supply for a private home.
Disc (ring) filters
This type of equipment is less common, although it is less prone to silting, has a larger filtration area, and can trap particles of different sizes.
The filter element is a set of polymer disks, on the surface of which scratches of varying depths are applied. When assembled, the disks are pressed tightly against each other, water passes through the hollows in the disks, and particles of larger diameter settle on them. The movement of water is spiral-shaped, so that suspended matter is removed efficiently.
When the water purification filter becomes clogged, the discs are removed from the housing, pulled apart and washed. After that they put it in place. The discs must be replaced periodically; the service life of the filter element depends on the amount of contamination and the quality of the discs themselves. There are models with automatic flushing.
Mounted into a pipe break, the bulb can be directed up or down (see installation instructions).
Inexpensive types of filters for purifying water for drinking purposes
Water purified from mechanical impurities can be used for domestic needs and supplied to household appliances, but it is only suitable for drinking or cooking - after boiling. In order to drink it without boiling, fine filters are needed that retain a significant part of the substances dissolved in the water and disinfect it. Let's look at how to make tap water drinkable and the types of water purification filters that can be used.
Filter jug
The simplest, but not very productive way to make tap water drinkable is to pass it through a filter jug. Cleaning occurs in a replaceable cartridge through which water passes. A good cartridge contains the following filter media:
- polypropylene fibers for sedimentation of residual mechanical impurities;
- activated carbon with additives to remove microorganisms and chlorine compounds;
- ion exchange resin for removing manganese and calcium salts, radionuclides, iron compounds, heavy metals;
- porous activated carbon for water clarification, sedimentation of organic matter.
Filter jug - simple, cheap
Filter jugs differ in the composition of the cartridge, its resource (how much water can be purified) and volume. The smallest models of tabletop filters can purify 1.5-1.6 liters of water at a time, the largest - about 4 liters. Just keep in mind that in the column “filter volume” the volume of the bowl is indicated, the useful volume (the amount of purified water) is much less - about half.
| Name | Bowl volume | Cleaning module resource | Degree of purification | Additional devices | Price |
|---|---|---|---|---|---|
| AQUAPHOR Art "Ice Age" | 3.8 liters | 300 l | 4-6$ | ||
| AQUAPHOR Prestige | 2.8 l | 300 l | Slightly reduces water hardness, removes mechanical and organic impurities, active chlorine, heavy metals | Resource indicator | 5-6$ |
| AQUAPHOR Premium "Dachny" | 3.8 l | 300 l | Reduces water hardness, removes mechanical and organic impurities, active chlorine, heavy metals | Large funnel - 1.7 l | 8-10$ |
| Filter jug Barrier Extra | 2.5 l | 350 l | 5-6$ | ||
| Filter jug Barrier Grand Neo | 4.2 l | 350 l | Depending on the filter type | Cassettes for different types of water, they add + to the cost of the jug | 8-10$ |
| Filter jug Barrier Smart | 3.3 l | 350 l | Depending on the filter type | Cassettes for different types of water they come with + cost + mechanical resource indicator | 9-11$ |
| Geyser Aquarius filter jug | 3.7 l | 300 l | For hard water with bacterial treatment | Cartridge replacement indicator | 9-11$ |
| Filter jug Geyser Hercules | 4 l | 300 l | From heavy metals, iron, organic compounds, chlorine | Receiving funnel 2 l | 7-10$ |
Filter nozzle for faucet
A very compact filter for running tap water that fits onto the tap. Cleansing speed - from 200 ml/min to 6 l/min. The degree of purification depends on the composition of the filter part, but is usually not much different from jug filters.
According to the method of operation, there are two types of filters on the faucet - some are put on immediately before use, others have the ability to switch to the “without cleaning” mode. The second option is definitely more convenient, but the switches often break. As a temporary measure, this is an excellent solution, but “permanently” it is better to choose another device.
| Name | Performance | Cassette resource | What cleanses | Manufacturer country | Price |
|---|---|---|---|---|---|
| Defort DWF-600 | up to 20 l/hour | 3000-5000 l | China | 2$ | |
| Defort DWF-500 | up to 20 l/hour | 3000-5000 l or 6 months | organic substances, pesticides, heavy metals, chlorine and radioactive elements | China | 2$ |
| Aquaphor Modern-1 | 1-1.2 l/min | 40000 l | from active chlorine, lead, cadmium, phenols, benzenes, pesticides | Russia | 13-15$ |
| Aquaphor "B300" with bacterial purification | 0.3 l/min | 1000 l | recommended for use in case of possible bacterial contamination of water | Russia | 4-5$ |
| Geyser Euro | 0.5 l/min | 3000 l | carcinogenic and organic compounds, chlorine, iron, heavy metals, nitrates, pesticides and microorganisms | Russia | 13-15$ |
| Philips WP-3861 | 2 l/min | 2000 l | chlorine compounds | 180$ | |
| Sorbent RODNIK-ZM | 2 l/min | 3600 l | free chlorine removal, iron removal | 8-10$ |
Filters under/on the sink - a way to get a large amount of drinking water
For greater productivity and better water purification, filters are used that are installed under or on the sink; they can also be mounted on the wall.
There are two types of such systems - cartridge and reverse osmosis systems. Cartridge ones are cheaper, and this is their advantage, but the disadvantage is that you need to monitor the condition of the filter element and change it on time, otherwise all the accumulated dirt goes into the water.
Reverse osmosis systems are more technologically advanced equipment that have a much higher cost, but the quality of cleaning and productivity are much higher. These water treatment plants use a multi-layer membrane, each layer of which traps a specific type of contaminant.
Cartridge
In cartridge filters, the quality of cleaning depends on the number of cleaning stages - individual filter elements that “catch” a certain type of contaminant. There are single-stage systems, there are two, three and even four-stage filters.
Single-stage ones use universal inserts that have a multilayer structure. They are inexpensive, but it is difficult to predict whether you will be satisfied with the degree of cleaning. The composition of water in different regions is very different and it would be advisable to select/replace filters as needed. And so, we have to hope for the versatility of the liner.
In multi-stage cartridge filters, the housing consists of several flasks, each of which has a separate/special filter element that removes certain contaminants. The flasks are connected in series using overflows, flowing from one flask to another, the water is purified. In this case, it is possible to select the types of filters for water purification specifically for your analysis, which will undoubtedly improve the quality of purification.
| Cartridge filter name | Type | Number of cleaning stages | For what kind of water? | Cartridge life | Performance | Price |
|---|---|---|---|---|---|---|
| BWT Woda-Pure | Household washable | 1 cartridge + membrane | medium hard | 10,000 l or 6 months | 1.5-3 l/min | 70$ |
| Raifil PU897 BK1 PR (Big Blue 10”) | Trunk | 1 | cold tap water | 26$ | ||
| Geyser Lux | Under the sink | 3 | soft/medium/hard/ferruginous | 7000 l | 3 l/min | 70-85$ |
| GEYSER GEYSER-3 BIO | Under the sink | 3 + protection against viruses and bacteria | soft/hard/very hard/ironous | 7000 l | 3 l/min | 110-125$ |
| Geyser-1 Euro | Desktop option | 1 | normal/soft/hard | 7000 l | 1.5 l/min | 32-35$ |
| Pentek Slim Line 10 | Trunk | 1 | 19 l/min | 20$ | ||
| Expert M200 | Under the sink | 3 | normal/soft | 6,000 - 10,000 l depending on the cartridge | 1-2 l/min | 60-65$ |
| Brita On Line Active Plus | Under the sink | 1 | flow-through | 2 l/min | 80-85$ | |
| AQUAFILTER FP3-HJ-K1 | Under the sink | 4 + protection against bacteria and viruses | for cold water | 3 l/min | 60-90$ | |
| Barrier Expert Hard | Under the sink | 3 | for hard water | 10,000 l or 1 year | 2 l/min | 55-60 $ |
| Atoll D-31 (Patriot) | Under the sink | 3 | highly chlorinated water | 3.8 l/min | 67$ |
Tabletop cartridge filters for running water
The most inexpensive version of cartridge filters is installed next to the sink. These are miniature models that are small in size. They can be one or two stage; there is a small tap on the body. The filter is connected with hoses to a special outlet of the mixer; it can be connected directly to the water supply.
Trunk
These are usually single-stage cartridge filter flasks, which are placed after the mechanical filter. They remove a significant amount of impurities, making water suitable for drinking and protecting household appliances from the formation of scale and other deposits. Their disadvantage is the need to change filter elements.
For ease of monitoring the condition and degree of contamination, the flask is made transparent. If visible contamination occurs, replace the cartridge with another one. In some models, it is possible to independently restore the functionality of the cleaning element - it is washed under running water. In other models this is prohibited, so read the instructions carefully.
Multistage filters
They differ from those described above in a large number of flask cases, each of which contains a cartridge that removes various types of contaminants. The more stages of purification, the purer the resulting water. The composition of the filter elements must be selected for the specific composition of the water (carefully read the technical specifications and description).
These installations can also be installed on the main line, or they can be placed under the sink and receive high-quality drinking water.
Reverse Osmosis
The most advanced water purification technology today is reverse osmosis. It uses multilayer membranes that allow only water and oxygen molecules to pass through, preventing even the smallest contaminants from passing through. The water obtained is practically free of salts, which is also not good. This is precisely the disadvantage of reverse osmosis systems. To neutralize it, the plants are equipped with mineralizers that add the necessary minerals.
| Name | Number of cleaning stages | Lifetime/replacement frequency | Filtration speed | Notes | Price |
|---|---|---|---|---|---|
| Geyser Prestige 2 | 6 | 1 time per year | 0.15 l/min | Purified water storage tank 7.6 l | 70-85$ |
| Atoll A-450 (Patriot) | 6 | prefilters - 6 months, membrane -24-30 months, carbon postfilter - 6 months. | 120 l/day | There is an external tank | 115-130$ |
| Barrier Profi Osmo 100 | 6 | 1 step - from 3 to 6 months, 2 steps - every 5 - 6 months, 3 steps - from 3 to 6 months, 4 steps - from 12 to 18 months (up to 5000 liters), 5 steps - every 12 months | 12 l/hour | There is an external tank | 95-120$ |
| Aquaphor DWM 101S Morion (with mineralizer) | 6 | prefilters - 3-4 months, membrane - 18-24 months, post-filter mineralizer - 12 months. | 7.8 l/hour | External tank + mineralizer | 120-135$ |
| Barrier K-OSMOS (K-OSMOS) | 4 | 5000 l (no more than a year) | 200 l/day | External tank | 120-150$ |
| Atoll A-450 STD Compact | 5 | prefilters - 6 months, membrane - 24-30 months, carbon postfilter - 6 months. | 120 l/day | External tank | 150$ |
The disadvantages of this system include their low productivity - only one glass or so of clean water can flow per minute. It is clear that such a speed causes inconvenience, so that it is felt less, manufacturers complete the installations with tanks for purified water, to which taps are already connected.
Filters for purifying water from dissolved substances
In addition to mechanical impurities, tap water also contains a decent portion of the periodic table: iron, mercury, manganese, potassium, calcium (hardness salts from which scale is formed), etc. All of them can be removed, but different filters are needed for this.
To make water potable, different types of filters are used to purify water.
To remove iron
Most often, large amounts of iron are present in water from wells or wells. It gives the water a reddish tint and a specific taste, is deposited on the walls of plumbing fixtures, and clogs shut-off valves, so it is advisable to remove it. It makes sense to do this if the amount of iron exceeds 2 mg/l.
Divalent iron dissolved in water can be removed from the water using a catalytic filter. This is a large cylinder into which catalysts are poured, the work is controlled by a small processor, that is, this equipment requires a power supply.
The backfill located in the catalytic filter greatly accelerates the process of oxidation of divalent iron and its precipitation. Depending on the backfill, impurities of manganese, chlorine, and other substances dissolved in water may also be removed, and mechanical particles will also settle to the bottom during the cleaning process. Removal of accumulated deposits occurs according to a given schedule, usually at night. The backfill is washed under the pressure of water, everything is drained into the sewer, and the water supply is stopped during washing. Catalytic filters are complex and expensive equipment, but they are the most durable available.
Another way to remove iron and water is aeration. Water is supplied in the form of a fine suspension (through nozzles) into a cylinder with a forced air pump. The iron in it reacts with oxygen in the air and its oxides are filtered out at the outlet. There are two types of filters for purifying water of this type - pressure and non-pressure. For more active oxidation, an oxidizing agent—hydrogen peroxide or sodium hypochlorite—can be supplied to these installations. In this case, biological purification of water is also carried out - from microbes and bacteria.
Purification of water from hardness salts
To soften water, filters with ion exchange resins are used. In the process of interaction with water, harmful impurities are replaced with neutral or beneficial ones (increasing the amount of iodine and fluorine).
Externally, this equipment is a tank partially filled with ion exchange material. Paired with it is a second similar regenerator tank filled with a highly concentrated salt solution (a special one is sold in tablets, highly purified).
The advantages of filters for water purification of this type are high performance, low noise level during operation, and rare replacement of the backfill (it lasts for 5-7 years). For water softening, ion exchange filters are the best choice. Disadvantages - the need to use a regeneration tank with a concentrated saline solution. To get drinking water, you need to install an activated carbon filter.
Cleaning method
Mechanical water filtration is a purification method that is aimed at extracting different types of particles from water by filtering it through special materials. allow you to remove sand, silt, turbidity, scale, and other suspended matter coming with the source water from water. Salt-containing macroelements, such as calcium, magnesium cations and bicarbonate anions dissolved in water, cannot be removed by this method.
In the water treatment system, when drawing water, filter elements for rough mechanical cleaning are installed. They are capable of retaining large suspensions and impurities from water coming from a well, village water supply system and well. Preliminary mechanical filtration ensures the normal operation of subsequent modules of the entire cleaning system, retaining large mechanical particles.
Filter modification
The mechanical filtration system uses filters of various modifications, which have their own advantages and features. For each object, the selection of the optimal solution is made individually. Filter elements for coarse mechanical filters are as follows: a cast mud filter with a mesh element that provides protection against suspensions and particles measuring 400 microns or more. This inexpensive option is sold in any specialty store. There are also mesh filters with direct flushing; the filter element is a mesh with a mesh size of 500 to 100 microns. Using direct flushing, filtered particles are easily washed into the drain by hand.
Coarse filters
Mechanical filtration of water can be carried out by a mesh filter equipped with a pressure reducer; it is a simple combination of a flush filter element with a low-pressure valve that protects mains and water consumption devices from unnecessary pressure fluctuations. Mechanical water filtration can be carried out with a similar device with backwashing; if there is a washing machine, filtered contaminants are washed off using the backwashing method.
Fine filters
After the water treatment system, fine mechanical filters are installed, which provide “final” polishing of the water. That is, they retain fine mechanical particles formed during minor wear of the filter media during washing of the backfill filters. Mechanical fine filtration of water allows you to avoid the “shadow effect” the next time water is supplied to a special disinfection installation with UV rays. Moreover, in the process of this filtration using a filter with a carbon cartridge, it is possible to significantly improve the organoleptic characteristics of the purified water - smell, taste.
Fine mechanical filtration of water is carried out by cartridge filters that remove active free chlorine and organic and organochlorine compounds. For example, a main filter element with a replaceable cartridge that must be changed in a timely manner. There is no need to rinse the filter. Mechanical suspensions and particles larger than 5-10 microns are effectively removed by a multi-cartridge fine filter. In its design of filter elements, thin-layer filtration is carried out through a highly porous material, thereby reducing the color and turbidity of the water.
Two types of filtration
There are two types of filtration in mechanical water purification: purification through film filtration and filtering. The last type of mechanical water filtration is based on the retention of particles by filter material, and is also called. The type of film cleaning is carried out due to a film that covers the filter material and retains the smallest suspensions and particles, which allows for higher purification. Thanks to sedimentation and mechanical filtration, it is possible to remove almost 60% of impurities from water. Of course, this is a low degree of purity of the purified water, so more expensive and effective purification methods are used to improve its quality. Mechanical water filtration- this is the cheapest cleaning method; in fact, it is only preparing it for deeper cleansing using chemical and biological methods.
Modern centralized water supply communications, as we all know, take water from natural sources - freshwater rivers, and after processing it at special treatment plants (industrial filters are used to purify water), it seems to become suitable for consumption.
But, unfortunately, even modern treatment plants, which have at least 14 stages of mechanical and chemical water purification, cannot always cope with all the impurities contained in river water.
In addition to the microorganisms themselves contained in river water, there are chemicals and heavy particles - the results of environmental pollution by industry. In addition, when passing through a metal water supply, water also picks up iron particles that have peeled off from the inner walls.
As a result, a significant part of this garbage reaches your tap in the apartment along with “drinking” water. It’s clear that consuming all this into the body can have health consequences; boiling water does little to help, so it’s worth playing it safe and installing a filter in your own water supply to purify drinking water.
Types of filters for water purification according to purification method
Although the environment is bad and this is reflected in the water, it is still encouraging that various types of water filters have appeared on the market, when choosing which, the first thing you should pay attention to is the cleaning method that is used in one or another type of water filter.
The method of purifying water with a filter determines its efficiency, durability, and cost, including consumables (cartridges).
So, today there are as many as six types of water filter materials, their list is as follows:
- mechanical water purification filters;
- ion exchange filters for water purification;
- reverse osmosis water purification filters;
- filters using physical and chemical methods of water purification;
- electric filters for water purification.
The lower you go on this list, the more high-tech device for purifying drinking water in domestic conditions you can see. It is also important to note that at the same time the wear resistance of the device increases, and the latter does not even have used elements.
Mechanical water purification filters
are used to clean it from large impurities with a particle size of 5-50 microns.
To do this, they contain special cleaning metal meshes, through the cells of which water, chemical compounds and small particles pass, and coarse particles are retained.
There are also disk cleaning systems, and, in addition, there is a separate class - pre-filters, which are installed as an element of the plumbing system to purify water from coarse impurities.
used to soften water, that is, to remove from it the smallest particles of metals, Fe, Mn, Ca, Mg ions dissolved in water.
For this purpose, so-called ion exchangers are used - substances that select ions of these metals from water, thus reducing their concentration.
Previously, ion exchange filters used natural-origin ion exchangers – sulfonated carbons and zeolites. However, modern filters operating on this principle contain modern synthetic ion exchange resins, which are more durable, and the quality of cleaning is slightly better.
Reverse osmosis water purification filters
, they are also called membrane filters for water purification - they are capable of purifying water from almost all impurities existing in it, that is, both from ions and metal particles, and from chemicals, and even moreover, from microorganisms.
The essence of reverse osmosis purification is to pass water through a special semi-permeable membrane, and this is only possible under some pressure.
The membrane (consisting of several layers) retains impurities (each layer is designed for a certain type of impurity), thus, water, percolating through it and back, turns from a more concentrated suspension into a less concentrated one, which is actually called reverse osmosis.
Biological water purification filters
are designed to remove organic contaminants that are dissolved in it and mechanical cleaning filters are useless here.
The essence of the purification method is microorganisms, that is, special microbes that essentially feed on these organic impurities and process/decompose them into nitrates.
As a rule, it takes time for microorganisms to process contaminants, that is, the design of such filters does not imply a flow-through cleaning method; in fact, they are containers in which water settles for a time that depends on its volume and the type of microorganisms.
Filters using physical and chemical water purification methods
They are used to remove impurities dissolved in water; they do not help remove particles at all, so you need to install filters in front of them for rough water purification.
Modern water filters are equipped with special solid substances - adsorbents, which selectively absorb chemicals and allow water to pass through - this phenomenon, or more precisely, the process, is called sorption.
Adsorbents can be different, for example, clay, sawdust, peat, ash. However, the most effective and most used element in modern water filters is activated carbon.
Electrical water purification filters
used for filtration from dissolved contaminants that can be oxidized - chlorine, manganese, iron, hydrogen sulfide, petroleum products, heavy metal salts, organochlorine compounds, etc.
Such filters perform cleaning by producing ozone gas from oxygen in water under the influence of electric current. The ozone produced is a powerful oxidizer and sterilizer, which, by binding to harmful substances, oxidizing them, breaks them down into elements, making them safer, or evaporates them, turning them into gaseous form, or turning them into sediment. Moreover, after this it turns back into oxygen.
Unlike many other filters, they have a wider range of purification, that is, indicators such as odors, tastes, and color of water are also filtered. In addition, it has a pronounced disarming property; viruses and bacteria, algae and fungal spores, and other microorganisms are destroyed.
In addition, there are electric water purification filters that operate on the principle of ultraviolet radiation; it also has a good bactericidal effect, and also significantly reduces the concentration of other substances, reagents such as chlorine, etc.
Types of water purification filters by design
The choice of filter according to the method of water purification is, of course, very important, but there is another difference - the design of the filter for water purification.
The filtration speed, durability and clogging rate, types of components/consumables, and, ultimately, the cost of both it and consumables may depend on which water filter to choose based on design.
Modern types of filters for water purification can be divided into three design options according to their design:
- water filters of pitcher design;
- water filters of filling type design;
- cartridge water filters.
It is worth noting that the fourth type of filters - electric filters, which in their design have a device for generating ozone, are not considered here, since the system is very complex, and in general there is no need to know it, you will not have to disassemble it, since there are no consumables he doesn't have to replace them.
Water filters of pitcher design
consist of two containers - a container for water purification and a container for purified water. Water is poured through the top of the jug, and it ends up in the first container in which the filter is installed. Under the influence of its own gravity, the water seeps through the filter and ends up in the lower container for purified water, from where, if you tilt the jug, it flows out through the drain hole.
The filter usually uses activated carbon, sometimes with an admixture of silver (silver has the property of destroying microorganisms).
As for the performance of this filter design, we can say that it is the least than that of any other types of water filters and is no more than 5-10 l/h.
Load-type water filters
They are a body design in the shape of an oblong cylinder, which is conventionally divided into several levels, each of which contains a certain type of filler aimed at purifying water from a certain type of pollution.
Thus, the lower part of the housing container, as a rule, is covered with a substrate of fine gravel, fine-grained filter filler is poured on top of it, and several more layers of various filtering bulk materials are poured on top, among which may be sorbents and ion exchangers.
Cylinder filters (as they are also called) operate, in other words, on the principle of a drainage distribution system; Their performance is sufficient to use them in everyday life.
Cartridge water filters
are devices consisting of one or more housings (depending on the degree and types of cleaning), inside which water passes through filter cartridges. Moreover, the design of the housing is such that it can be easily disassembled to replace a clogged cartridge.
If the device consists of several housings, this most often means that each of them contains a cartridge of filter material aimed at purifying water from a certain type of impurity.
Thus, cartridges for water purification can accommodate a wide variety of filter materials: activated carbon, ion exchange fillers, mechanical cleaning meshes, semi-permeable membranes and other materials for purification using reverse osmosis.
The throughput capacity of cartridge-type filters is no more than 600 l/h, due to which they are successfully used in domestic conditions.
Types of water purification filters by degree of purification
Perhaps the most important parameter to guide how to choose a water filter is the degree of purification. Based on this criterion, you can choose a filter without even delving into its design, operating principle and cleaning stages, however, it is still important to know these aspects.
At the same time, household filters contain many different filter materials; only by combining them can a full degree of water purification be achieved from many types of impurities.
So, there are only three types of filters according to the degree of water purification:
- elementary water purification filter (single-stage);
- medium water purification filter (2-3 stages of purification);
- filter of high degree of water purification (up to 5 stages).
The list presents the basic standards, but of course, there may be different variations of filters that can accommodate four and six stages of purification; in fact, the cleaning principle is the same, duplicate filters are possible for the so-called “additional purification”.
Elementary filter
Structurally it is a filter jug. It has a filter with one filter element - activated carbon, but may also have auxiliary substances, for example, silver, which disinfects water.
Also among the simplest filters are other coarse water filters and fine water filters built into the plumbing system. Coarse filters are installed to prevent clogging of the water supply system with large particles of various origins, mainly metal.
A fine water filter is installed to filter water, which is later used as drinking water; however, many impurities still exist after such purification.
Such filters can purify water from elementary mechanical impurities (metal particles, partly from heavy metal salts) and from dissolved chlorine. If there is a silver component in the filter, it partially destroys microorganisms.
capable of a little more, for example, the simplest modification, which has two stages of purification, rids the water of the smallest mechanical impurities.
At the same time, the first stage of purification, as a rule, occurs through a cleaning mesh, which retains large mechanical impurities, while the second stage of purification - fine cleaning - occurs in the process of passing water through an absorbent - activated carbon, due to which even the smallest particles are retained.
If we are talking about a three-stage medium filter, then one more quality is added here: water softening. This happens due to the presence of a third stage of purification, which consists of passing water through an ion-exchange filter material - ion-exchange resin or other ionites (sulfonated carbons, zeolites). Pressed carbon can also be used, which may contain silver or hexamethophosphate.
High purity water filter
are high-tech water purification devices that are capable of purifying water from all types of contaminants.
The simplest types of these filters are ozone electric filters, but there is also a whole system of filters for water purification, which consists of many different filter materials and contains as many as five stages of water purification from impurities.
At the first stage, mechanical impurities are removed using an appropriate filter material (foamed polypropylene, membrane or mesh filter).
The second stage of purification occurs using a sorbent - activated carbon, which removes gases, chlorine, organochlorine compounds and fine impurities.
The third stage is safety additional purification from fine impurities and organochlorine substances to increase the shelf life of the next filter material.
The fourth stage is classic purification using a thin-film membrane that filters water using reverse osmosis. After this comes the final, fifth stage - filtration with a carbon post-filter.
Types of filters for water purification by configuration and installation method
Where to place the water purification filter also plays an important role, because it must either be well located and fit into the environment. Or another option is to be completely hidden and placed somewhere out of sight - a good solution if the filter is very bulky.
Modern filters, in addition to all the above features, also have differences in configuration and installation method. Thus, you can choose a filter for water purification based on the types of their connection:
- filter with connection to the tap;
- filter with permanent connection under the sink.
Of course, many different housing options and individual sections give the impression that there are a lot of different configurations, but the list represents all the currently existing types of filters in terms of their configuration, as well as the method of connection.
, in other words, a faucet attachment. It connects directly to the outlet of the mixer and is a small container.
Water under pressure passes through the filter material located in it and is purified in one or two stages of purification - the volume of the housing itself simply will not allow it anymore. In addition, the productivity is low - 0.3-0.5 l/min.
Such filters are quite cheap, have replaceable consumables (cartridges), but again, due to the small volume of the filter, they quickly become clogged and are only capable of simple cleaning from mechanical impurities and chlorine.
Filter with connection to the sink
or “sink water purifier” is one of the most popular configurations of water purifying household appliances. It is connected to the mixer using a flexible hose, and the device itself is installed near or on the sink.
After stopping work, the hose is removed, or the second option is to remain in place if it is connected to a special outlet provided on the mixer itself. In the second case, the mixer has a special switch for supplying water to the filter and to the main drain.
The device itself can be of various shapes and sizes depending on the degree of purification and filtration method. Often they can be presented as flow-through filters for water purification, that is, they have several containers, each containing a certain stage of purification.
The productivity of this filter configuration is 1-1.5 l/min, which is quite acceptable for domestic use. However, there is also a minus - this is that it takes up space on the table near the sink, and sometimes a lot.
Filter with permanent connection under the sink
considered the best in terms of both convenience and water purification. This filter is connected directly to the water supply system using a manifold or tee connection method, but the device itself must be located under the sink.
In this case, the sink itself must be able to connect a second tap, which, in fact, will serve as an outlet for this water purification device.
As a rule, these devices are multi-stage filter systems that are characterized by durability and the highest quality of water purification. Of course, the cost of such devices is much higher, and there is a wide variety of filter materials, cartridges and other components for them, because the matter is not limited to just a mesh and a carbon filter.
Now you know by what criteria to choose a household filter for drinking water purification, how to choose a flow filter, which water filters are better, what design of household water filters, types of filter materials for water filters and much more.
But what is also important is what kind of system you have installed and what operating pressure is in it (are there any surges), because the durability of cleaning household appliances depends on this.
Modern humanity, increasingly experiencing the consequences of industrialization, is often faced with the problem of the need to purify water. Considering that most of the water that flows from our taps comes from open bodies of water into which a variety of toxic waste flows, the problem of its filtration comes to the fore. There are various ways to filter water, they depend on the nature of the contaminants. It is best to use several cleaning methods at once, combining them. Let's look at some of them.
Navigator by methods
Method 1. Mechanical filtration
During mechanical cleaning, filters are used that are capable of capturing and retaining particles of solid materials suspended in water. The degree of purification in such filters depends on the diameter of the holes in them. The smaller the holes, the more solid particles will be retained in the filter. If it is necessary to purify a large amount of water taken from open reservoirs, entire filter systems with ever-decreasing holes are used. In this case, the water is first allowed to settle so that most of the solid particles settle to the bottom. This method allows you to gradually purify the water, bringing it to an acceptable state. Of course, it will not be possible to get rid of bacteria in the water, since they are smaller than the diameter of the holes in most filters. In this case, it is recommended to additionally use other cleaning methods or combine them. For example, silver ions are added to household filters, which have a detrimental effect on microorganisms.
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Method 2. Ion exchange
This filtration method is used if it is necessary to purify water from salts of heavy metals or nitrates. For cleaning, a special sorbent is used, which acts as follows: some harmful salt ions (magnesium and calcium) are removed from the water and neutral ions, for example, sodium salts, take their place.
Method 3. Filtration using electrochemistry
This method is approved for use for water purification for industry. It consists of exposing water to electrical discharges, during which oxidation and reduction reactions occur. Exposure of water to strong current discharges leads to its complete purification of harmful microorganisms, but there are also side effects. It is never known in advance exactly what substances were dissolved in water. And under the influence of current, they can change their structure and turn into dangerous components. Therefore, although such filtration is quite inexpensive, it is not used for the population.
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Method 4. Use of sorbents
This method of water purification is applied as follows. A special sorbent is placed in the filter, through which water is passed. It has the ability to absorb harmful impurities, making the water clean. Activated carbon is often used as a sorbent. A popular natural sorbent is also zeolite, which allows you to purify water from chemicals dissolved in it, pathogenic microorganisms, carcinogens, heavy radioactive salts, in return enriching it with useful salts.
Method 5. Reverse osmosis method
With this cleaning method, special membranes are used through which contaminated water is passed under pressure. The membranes are a fine sieve in which almost all particles are retained, including even dissolved salts. The water becomes distilled. However, such a membrane itself does not retain pathogenic microorganisms, so additionally activated carbon is used. Such filtration is quite expensive, its use at the outlet allows you to obtain no more than thirty percent of the total amount of purified water, the rest is waste. In addition, the productivity of the membranes is low and the water is so purified that it is also devoid of useful substances.
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Method 6. Distillation
Quite an expensive and low-productivity method. It is used in pharmacology, medicine and those industries that require distilled water. This water is not suitable for drinking. Since distillation does not rid water of harmful microorganisms, it is additionally used for purification with activated carbon.
