Which water filter to choose for a house or apartment

The quality of modern drinking water, regardless of the method of its supply, leaves much to be desired. This applies not only to central water supply, but also to well water, and even artesian wells. In most cases, the problem with pollution of various kinds can be solved with the help of filters. This article will talk about various filtration methods, how and which filter to choose for water purification, when it is advisable to use it, and when it is not recommended. General selection criteria and operational features of equipment.

Water purification methods

Modern models of household filters have different principles of operation. Their design, active substances, the presence and location of filter elements differ significantly. Before you start choosing a filter, you need to understand what methods of water purification exist and how they affect water quality.

mechanical cleaning

Mechanical cleaning is used to remove solid impurities from water - sand, rust from pipes, as well as various salts and chemical additives.

There are the following types of mechanical filter elements:

Mesh- a grid is used as the main element, the cell size of which depends on the level of water pollution and is 20-500 microns.

Made from synthetic fibers- a rope or a tourniquet is wound around the mesh cylinder, which trap large contaminants. At the same time, in the process of cleaning and accumulation of harmful substances, the material changes color.

Sorption cleaning

The principle of operation is based on the phenomenon of adsorption - the retention of microparticles of pollution by the outer surface of filtering solids. The active substance is usually activated charcoal. Budget models are equipped with cartridges containing wood (birch) activated carbon. More expensive and efficient cartridges are refilled with coconut shell activated carbon, which has an adsorption capacity 4 times higher.

The main purpose is to remove various organic compounds and residual active chlorine, as well as odors associated with these substances. Filter elements consisting exclusively of carbon have a limited spectrum of action; ion exchangers are mixed into the cartridge to expand it. Combined cartridges will be able to remove herbicides, pesticides, asbestos particles, oil products, heavy metal ions.

By adsorbing organic substances, carbon filters can become a breeding ground for bacteria, so they can be used to purify previously disinfected water. Restoration of sorption filters at home is impossible and after exhausting their limit, they must be disposed of.

Carbon sorbent cartridges

Combined sorbent cartridge

Ion exchange treatment

Ion exchange filter elements are rarely used as independent devices. They are an integral part of multi-component household cleaning devices. The main task is to reduce the hardness of water. It is carried out due to the ion exchange reaction (substitution), which is based on the binding of calcium and magnesium ions in water into insoluble complexes. As an active element, special synthetic resins with alkali metal salts: potassium and sodium are used. It is these elements that react with hardness salts (calcium and magnesium) and retain them.

There are two types of ion exchange resins, anionic and cationic. They bind hardness salts due to various types of chemical reactions, but during their operation for the average consumer, the difference is practically not noticeable. Most ion exchange resin cartridges can be reconditioned at home. It is enough to wash them with a strong solution of common salt for the reverse substitution reaction to occur.

IMPORTANT! After the ion filter, the water must be cleaned with a carbon filter without fail.

The main disadvantage of the ion-exchange cleaning method is a small resource of functioning before the recovery process. Depending on the model, it can range from 200 to 800 liters.

Cleaning with reverse osmosis membranes

Many water filter vendors refer to ultra-fine cleaning devices as combination devices that combine several cleaning methods. This is not true. Ultrafine purification involves filtering water using membranes. With ultrafine cleaning, water under pressure (up to 6 atmospheres for some models) is fed into a membrane filter with a pore size of 0.0015 to 0.1 microns. As a result of such purification, all harmful impurities remain on the surface of the membranes, and only water molecules pass through the membrane. Recently, with the development of nanotechnology, hollow fiber capillary membranes have begun to be used. Their use significantly reduces the cost of both the maintenance of the treatment plant and its cost.

Ultrafiltration allows you to remove mechanical impurities, organic substances, colloidal silicon, excess iron and manganese, and to carry out almost complete disinfection of the liquid. The main disadvantage of this method is the rather high cost of installation and the need for constant monitoring of the condition of the filter membranes and their systematic washing and/or replacement.

Module with installed reverse osmosis membrane.

Electrochemical cleaning

The electrochemical method of drinking water purification is used in household filtering devices in conjunction with other methods. The main task is to improve the physicochemical and organoleptic properties of drinking water.

Installations have a rather complex structure consisting of:

1. Electrochemical reactor;

2. Sludge collector - for most models it is installed at the top of the device;

3. Floating cone plug blocking the top hole.

4. An electrode block containing three groups of electrodes:

• І and ІІ groups form an electrocoagulating pair package;
• III - consists of electroflotation electrodes.

5. Switching device - redistributing positive and negative energy charges to cathode and anode electrode packages;

6. Some models have final filters.

Household water electrolyzer.

UV disinfection

Modules for water disinfection by ultraviolet irradiation are used in conjunction with other filtration methods. The principle of operation is based on the treatment of the water flow with intense UV radiation in the wave range of 250-260 nm. This radiation penetrates the cell walls of viruses and bacteria, causing the destruction of the body's DNA and RNA.

This method is much more efficient and safer for human health than the classical reagent method, in which water is treated with various oxidizing agents: chlorine, chlorine dioxide, sodium hypochlorite, etc. The scope of the UV disinfection plant is associated with its rather large dimensions and high cost. Usually these are cottages, dachas and buildings that use artesian wells or autonomous wells for the water supply system.

The UV module consists of the following key elements:

1. Power Supply;

2. Metal case;

3. UV source:

• Mercury-quartz lamp;
• Mercury-argon lamp;

4. Protective (sealed) quartz casing - prevents overcooling of the lamps by water flow.

Depending on the declared performance, several UV lamps can be placed in one housing. The main disadvantage of this method is its complete energy dependence. Also, for efficient operation, it is necessary that the incoming water be of a certain quality, its physico-chemical parameters should not exceed:

• Turbidity< 2 мг/л;
• Chroma< 20°;
• The content of iron impurities< 1 мг/л.

In what case can one or another type of water filter be used

The effectiveness of cleaning devices depends on which water filter to choose in each case. Modern manufacturers produce many models of various cleaning devices and water filters. Many of them do not carry any specific benefit, and sometimes, if installed incorrectly or in violation of operating conditions, they are a source of biological contamination.

Mud filters

Gryazevik refers to the means of mechanical water purification. It is a device in which there is a forced change in the direction of water movement. The stream passes through a special mesh, leaving solid impurities on it.

The mudguard consists of:

Scheme of the structure of the sump: 1. Plug made of brass; 2. Sealing gasket made of Teflon or silicone; 3. Stainless steel filter mesh - AISI 316; 4. Body - usually nickel-plated brass CW617N.

The most common household models with various types of threads for fastening:
VT.192, VT.191, VT.190
VT.385, VT.387, VT.388

Taking into account the peculiarities of the material, the mud collectors can be used for preliminary filtration of both cold and hot water with temperatures up to 150°C. They are installed at the entrance to the water supply system of an apartment or house, immediately behind the stop valves (faucet). One of the purposes of this filter is to protect water meters from the ingress of large mechanical impurities. They cannot produce finer cleaning.

IMPORTANT! It is necessary to carefully monitor the direction of installation of the device relative to the flow of water, usually it is indicated by an arrow on the body.

Prefilters

For water supplied to apartments and houses from a centralized water supply, the main type of pollution is:

• Excess active chlorine;
• Organics;
• Oxidized iron (from worn pipelines).

Pre-filters are used to purify drinking water from solid impurities, which not only significantly impair its taste, but can also damage household appliances (washing machines and dishwashers).

The design consists of:

1. Bracket for fastening;
2. Detachable connections for connection to the water supply system;
3. Cases made of transparent plastic;
4. Replaceable filter cartridge made of synthetic fibers.

Appropriateness of use. It is advisable to use pre-filters in purification systems if the water entering the house has a significant content of solid impurities. The choice of a particular model depends on the average volume of water consumption. They are used to protect gas boilers and water heaters, as well as washing machines and dishwashers, from getting into the equipment of large mechanical impurities. In fact, they perform the same functions as mud collectors, but they have a higher degree of purification, dimensions, filtration rate and resource.

Filter jugs

This type of filter is widely known, usually a pitcher filter consists of the following elements:

Jug filter design: 1. Lid; 2. Filter replacement calendar; 3. Locking latch; 4. Handle; 5. Spout for draining purified water; 6. Capacity in the form of a funnel for filling water; 7. Housing; 8. Replaceable filter cartridge.

Appropriateness of use. Pitcher filters are used as an alternative device for purifying drinking water if the apartment water supply system is not equipped with stationary treatment devices. The degree of their purification is somewhat worse, however, the cost is disproportionately cheaper, which made these filters very popular. Despite a slightly worse degree of purification, with the help of these filters it is possible to obtain drinking water. Filter jugs are equipped with various types of cartridges, which are selected depending on the contaminants present in the water.

Dispensers (purifiers)

Conventional, budget dispenser models that use purified bottled water do not have filters at all. But more expensive devices that connect to a centralized water supply (purifiers) have their own cleaning system.

Appearance and diagram of a universal office dispenser with a filtration system:

It consists of: 1. A mechanical filter that removes solid particles up to 5 microns in size; 2. Carbon sorption cartridge that removes excess chlorine and organic matter; 3. Ultrafiltration membranes that remove bacteria, viruses and excess dissolved salts; 4. Carbon post-filter to remove unpleasant odors.

Appropriateness of use. Dispensers are water dispensing devices that are used mainly in offices.

Faucet nozzles

The filter nozzles on the faucet are mainly mechanical cleaning devices. They are divided into fixtures mounted directly on the mixer or freestanding.

Their main disadvantages are:

• Poor quality of water filtration;
• Reduced flow rate, most manufacturers produce models with a recommended flow rate of 1-1.5 l / min .;
• An insignificant resource, for "fine" filters it is 300-350 liters.

Appropriateness of use. The use of such devices is recommended only in the most extreme cases, when it is not possible to install a stationary treatment system, and the water quality is very poor. In all other cases, the use of filter nozzles on the tap is impractical.

Flow sorption filters

Inline sorption filters are a multi-stage filtration system consisting of 3-5 replaceable cartridges, each of which purifies water from a particular type of pollution. They are optimal in terms of price-quality ratio. Recommended for use with small and medium consumption of purified water.

The device of the main nodes of the flow filter: 1. Node for connecting water; 2. Filter for preliminary sorption or mechanical cleaning; 3. Deep sorption filter; 4. Knot for connecting a crane; 5. Filter for final cleaning and conditioning; 6. Faucet.

Appropriateness of use. Typically, such systems perform cleaning from mechanical solid impurities, active chlorine, iron, limestone and other chemical contaminants. When choosing a specific model, it is necessary to take into account not only the prevailing type of water pollution, but also the daily consumption rate. Most models are equipped with a separate faucet, so that domestic water is not filtered, which further increases the life of filter cartridges. It should be remembered that it is not advisable to use such systems for treating too hard water due to the very low resource of the ion exchange cartridge. After a certain resource is exhausted, the water will stop softening and scale will reappear in your kettle. To solve the problem of too hard water is possible only with the help of reverse osmosis systems, which will be discussed later.

Reverse osmosis systems

The reverse osmosis system is a balanced set of devices and filters for cleaning.

The device of the main components of the reverse osmosis system: 1. Filter-mineralizer; 2. Post-filter for conditioning; 3. Module with reverse osmosis membrane; 4. Storage capacity; 5. Mechanical cleaning filter; 6. Filter for sorption cleaning; 7. Sorption filter for final cleaning; 8. Faucet.
*(The set of filter modules will depend on the specific filter model).

It consists of the following components:

1. Pre-cleaning unit, which includes a mechanical, sorption and ultrafine filter.

2. Block with reverse osmosis membrane. The membrane consists of a polymer with a pore size of 1-15 angstroms for high purification devices and 10-70 angstroms for nano filtration plants.

REFERENCE: 1 micron is 10,000 angstroms.

3. Storage tank. Since the rate of water purification by reverse osmosis is rather low, a container must be provided in the system for the accumulation of filtered water. The volume of the tank must be selected in accordance with the daily consumption of drinking water.

4. Post-filter - installed after the storage tank to eliminate unpleasant odors and tastes.

5. Shut-off and connecting fittings. Given the low rate of reverse osmosis purification, it is not advisable to use filtered water for domestic needs, it is mainly used for cooking and drinking. Therefore, the system must have a separate faucet.

Water softeners

The process of water softening consists in reducing the amount of hardness salts, mainly chlorides and sulfates. For this, replaceable cartridges with a cation exchange resin are used, which adsorb salts from water, giving back hydrogen and sodium ions. The use of soft water is not only good for health, but also keeps household appliances in good condition. These filters are available in various capacities.

Appropriateness of use. Before purchasing and installing a filter with a cation exchange resin, it is necessary to check the level of water hardness. It is advisable to use softening if the water hardness index is higher than the recommended 1.0–2.0 mg-eq / l. It is also important to know that such filters do not purify water from metal salts and bacteria, their purpose is to soften water, which contains a large amount of hardness salts. If the water is supposed to be used for drinking, then it is worth taking care of the presence of sorption filters used to purify water from other harmful impurities. If a softener is to be used to protect washing machines from scale build-up, then one softener will suffice.

Results. If you want to get really high-quality water for cooking, tea, coffee and just drinking water, then you need to look towards flow-through sorption filters and reverse osmosis systems. No nozzles and jugs can replace them. It should be remembered that these systems are much more expensive. If you cannot afford the installation of such systems, then as an option, you can use a filter jug ​​with a specific cartridge.

Postfilters

Post-filters are used in reverse osmosis systems and in-line filter sets to eliminate unpleasant odors and improve the taste of purified water. As an active element, granular or powdered activated carbon in a polymer body is used. The placement of fittings for connection depends on the specific model and on which device the filter will be connected to. In addition, mineralizer filters are used in reverse osmosis systems. Since all useful minerals are removed from the water after passing through the oratnoosmatic membrane, such mineralizers are used to restore them. They restore the natural mineralogical composition of water.

Criteria for choosing a filter for water purification

We determine the contamination of water

The efficiency of the applied purification system, and therefore the quality of the filtered water, depends on the specifics of the contamination. Before determining which water filter to choose for your home, you need to make a comprehensive analysis of the water coming from the water supply. The analysis must be done regardless of whether water is taken from a well, an artesian well or a centralized water supply. Only after the analysis it will be clear which filter and with which filter elements is needed. Based on this, the filter is selected.

Water problems, their manifestations, causes and filters for elimination:

Problem	How does it manifest	Cause	Used filter or cartridge
Corrosive water at neutral pH.	Copper and bronze pipes and valves actively corrode with the appearance of greenish smudges.	The water is supersaturated with oxygen; the water was taken from the surface layers or from very deep wells.	Ion exchange cartridge.
hard water	Limestone scale on the heating elements of household appliances.	The presence of limestone, calcium and magnesium salts in the water.	Ion exchange cartridge.
Insoluble particles, sand, etc.	Silt sediment in the sink.	Clogged sump, excessive amount of pollution.	Install or increase the volume of the coarse mechanical filter.
Smell – fishy, ​​musty or woody	It usually appears during floods (from melting and rain).	Water intake from the surface together with organic compounds.	Sorption carbon cartridge + UV disinfector.
			Postfilter + UV disinfector.
The smell of chlorine	-	Excess chlorination.	Sorption cartridge of any type.
Smell of hydrogen sulfide (rotten eggs)	Formation of gray or yellow spots on dishes and sinks, unpleasant taste.	Presence of dissolved hydrogen sulfide and/or sulfur bacteria that cause hydrogen sulfide to form.	Sorption cartridges of any type.
			Sorption + UV disinfector (if the problem is bacteria)
Chemical smell of detergents	The water is slightly foamy.	Drainage from a septic tank into aquifers.	Sorption carbon cartridges.
The smell of petroleum products	-	Leakage of oil products into the aquifer.
Turbid water with a methane smell	-	The result of the decomposition of organic matter in the areas of oil production, aquifers pass through the site of the old landfill.
Smell of phenol (chemical)	-	Ingress of chemical effluents into aquifers.
			Sorbion cartridge.
brackish water	laxative effect.	Entry into aquifers of industrial effluents.	Ion exchange; cartridge.
Acidity	Metallic taste.	High iron content, natural hyperacidity over 4.5 pH.
ferruginous water	When washing, the laundry takes on a yellowish tint, when heated, the water turns brown.	The presence of ferrous iron in a concentration of more than 0.3 mg / l.	Sorption cartridge for water iron removal.

Filters for hot or cold water

The vast majority of filters are designed for cold water treatment. The upper temperature limit of such treatment systems is 35 - 40 0 ​​C. Therefore, if you need to clean hot water, you will have to look for filters whose temperature limit is at least 95 0 C.

Maximum performance

Filter performance is the ability to pass and clean a certain number of liters of water per minute. Reverse osmosis systems have the lowest productivity, because it takes a long time for water to pass through the reverse osmosis membrane. But so that users do not have to wait too long for the required amount of water to be collected, such devices are equipped with expansion tanks, where there is always a certain amount of prepared water. Also, jug filters have a small capacity. When choosing a filter, you need to determine how often you are going to use the filter and how much purified water you need during the day.

Filter module resource

Almost every filter has a filter module, which is designed to purify a certain amount of water. After the exhaustion of its resource, the filter module will not be able to provide the proper quality of water and must be replaced. Before choosing a filter, you can calculate the applied water consumption and, based on these calculations, choose one or another filter element. Please note that in systems with a multi-stage cleaning system, each cartridge has its own filtering capabilities and resource. This means that the cartridges will be replaced at different times, and not all at once.

Consumables, their cost and availability for sale

Before buying a specific filter model, you need to inquire about the availability of cartridges for sale and their cost. It often happens that the manufacturer puts a small price on the filtration system itself, but the cost of cartridges is disproportionately high, which leads to high maintenance costs for the system throughout the entire period of its use. In addition, find out if there are cartridges and consumables for sale in the city or region where you live. Sometimes it is difficult to buy certain filter modules and when they appear on sale, you have to buy a spare, which is also costly and inconvenient.

Counterfeits and unscrupulous manufacturers

Knowing how to choose a water filter is not enough, you still need to be able to distinguish quality products from fakes. There are many fakes of various goods in the world and filters are no exception. Having bought such equipment, there is a risk of giving money away, and the quality of water will remain at the same level.

To protect yourself from buying a fake, you need to pay attention to the following points:

• Prominence of the manufacturer
• Item price level
• Product appearance
• Availability of certificates
• The presence of a hologram, marking of special application, a unique serial number

Producer reputation. As in any other niche, there are manufacturers who have been working in this market for a long time and have proven themselves well. Each of them has its own developments and patents for various systems used for water treatment. The most famous manufacturers of household water filters are such companies as: Barrier, New Water, Aquaphor, Geyser, Atoll and others. when choosing a filter, you should focus on the products of these brands.

The value of the goods. The consumer opportunities of our citizens are at a low level, hence the desire to save money arises. When buying a filter, you need to be careful. If you see that the price of the model offered to you differs markedly from the average price in the market, then you should think about where this seller got this product from. If the product was purchased from an official supplier, but the price for it differs significantly from the price in other stores, then this is one hundred percent fake. After all, the seller cannot trade at a loss and give it away at cost also makes no sense.

The appearance of the goods. The cost can not always tell about the poor quality of the goods, because it can be set at the same level as with other sellers. Therefore, when buying the filter model you need, look at the quality of the material and assembly. a fake always differs from the original in various details. Pay attention to the seams of the flasks, the threads of the outlets for connecting to the water supply, the equipment, etc. Everything should be at the best level. In addition, pay attention to the quality of packaging - no one packs a fake in high-quality materials. Not meeting these little things to high standards may mean that you have a fake in front of you.

Availability of certificates. If you have any doubts, ask the seller to show a quality certificate for the products. At the same time, pay attention to the certificate must be genuine, and not be a photocopy of many years ago.

The presence of a hologram, marking of special application, a unique serial number. To protect their products, manufacturers supply them with various galagrams, documents with special markings, and some with unique serial numbers that can be verified for authenticity. It is enough to drive such a number into a special form posted on the official website of the manufacturer and you will receive an answer whether your model is genuine.

When choosing a filter, it must be remembered that only filters equipped with sorption, ion-exchange cartridges and / or modules with a reverse osmosis membrane can rid water of chlorine, dissolved iron salts, soften it, etc. It is impossible to produce high-quality water purification without using sorbents and / or reverse osmosis membranes. In addition, a high-quality filter will have several degrees of purification and, accordingly, cartridges. It is not possible to clean different impurities with the same cartridge or module. If they try to sell you some "miracle" filter that does not contain the above purification modules, while the manufacturer claims that it can purify water from all impurities, then they simply want to deceive you.

Operation and maintenance of filters

Any of the cartridges used in the cleaning system has its own resource, after which its performance must be replaced or disposed of. As a rule, it is expressed in the number of liters of treated water or the operating time, but taking into account the average daily water consumption per person. Mechanical cleaning filters must be periodically cleaned from accumulated contaminants. If you do not follow the rules of operation, the cleaning system can become a source of biological contamination.

Most companies produce unified cartridges for the entire line of filtering devices. If the cleaning device is a sequence of flasks. You can also use cartridges from other manufacturers, provided that the overall dimensions are suitable. Cutting or opening cartridges is strongly discouraged.