Almost every one of us thought about the quality of the consumed water. Buying bottled water daily is very expensive in practice, and tap water without further purification is completely unsuitable for this purpose. Do you agree?
It turns out that this problem is quite easy to handle. Using a reverse osmosis filter from a trusted manufacturer, you can be sure of the quality of the water used. In the huge assortment of reverse osmosis systems on the market, making the right choice is not easy, but we will help you find the right solution.
In this article, we will talk about the principles of operation of reverse osmosis filters, the criteria for their selection, provide an overview of models from the best manufacturers, and also give recommendations on the operation of filters. The material is accompanied by thematic photos and videos.
Forward and reverse osmosis
Natural osmosis is a phenomenon that underlies the metabolic process that occurs in living organisms. It provides a balanced state of salt and mineral metabolism.
Living cells are washed by blood and lymph, from these liquids through the membrane, which is a semi-permeable membrane, nutrients enter it, and waste products are removed back.
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The reverse osmosis system includes a group of filters that perform rough cleaning, softening, iron removal and ultrafine water treatment
In regions with hard water, there should be 5 filters in a water-purifying installation; in areas with soft water, 3x are enough
Modules with filter cartridges in reverse osmosis plants are located in strict order. Swapping them is unacceptable
The first in a series of cleaning components is a coarse filter that holds sand, rust and other particles up to 5 microns in size
After rough cleaning, fine cleaning is performed, for which water passes through a carbon pre-filter and a filter that holds particles up to 1 micron in size
After performing rough and fine cleaning, water enters the module with a membrane filter that holds not only the smallest mineral and organic particles, but also bacteria and viruses
At the bottom of the module with a membrane filter there is a flange for connecting a hose. The hose is discharged into the sewer, all water that has not passed through the membrane is discharged through it.
Water passing through the membrane filter is supplied to another carbon filter, then through a separately installed faucet to the consumer. To collect water prepared for consumption, a storage tank is included in the circuit
Reverse Osmosis Function
The number of filters in the cleaning system
The location of the modules in reverse osmosis
Mechanical filter
The following modules for water treatment
Osmosis membrane filter module
Hose connection hole
Water after membrane cleaning
The semi-permeable membrane has selective throughput. Having an electric charge on its outer surface, it repels mineral substances dissolved in water, whose molecules, as a result of hydrolysis, decompose into ions.
In the middle of the cell, these mineral substances carry special transport molecules through individual channels available in the cell membrane.
To simulate the process in the laboratory, take a vessel, divide it into 2 parts using a semipermeable membrane. On the right side of the septum, a highly concentrated aqueous solution of the mineral substance is poured, on the other hand the same, but in a much lower concentration.
In an effort to balance, the water on the left side goes to the right. The process continues until the concentration of solutions on both sides becomes the same.
With the achievement of an equal level of concentration, the height of the liquid columns located on different sides will turn out to be uneven. The difference in height will be directly proportional to the force that causes water to pass through the membrane and is called osmotic pressure.
The diagram illustrates the process of direct and reverse osmosis simulated in laboratory conditions
Reverse osmosis - a phenomenon directly opposite to natural osmosis. Everything in the same vessel, under the influence of external pressure on a solution of high concentration, water changes direction. The applied pressure simply pushes it through the membrane, freeing from the substances dissolved in it.
The concentration of the solution, which was already higher initially, rises further, while the smaller one continues to decrease. Through the membrane, as before, only water passes, but in a different direction.
We recommend an article on the topic: Reverse osmosis: the harm and benefits of membrane purification of tap water.
The principle of operation of such a filter
The principle of water purification using reverse osmosis is based on the fact that a concentrated aqueous solution is supplied under pressure into a container separated by a semipermeable membrane. Water filtered through the membrane gets into the second part of the tank, mineral substances remain outside, and then go into the sewer.
Filters consist of modules that are easily replaceable during operation. Each of them has a specific service life.
Phased water treatment. Passing through all the modules, the water is purified from all impurities, including useful ones, therefore experts advise to purchase systems with mineralizers
The system design includes several filter cartridges with activated carbon and porous polypropylene inside. With their help, water is freed from solid particles and organic impurities. At the first stage, when passing through a polypropylene filter, water is freed from particles with a minimum size of 0.5 microns.
The second filter is a carbon filter, with its help organic and chemical impurities are released from water, including oil products, pesticides, heavy metals and other substances. The last filter in front of the reverse osmosis membrane retains microscopic mechanical impurities; their size does not exceed 1 micron.
The main element in the system is the membrane, where water flows under pressure after rough pretreatment. Its pores with a size of 0.0001 microns do not pass anything but water molecules. When it passes through the post-filter, the final purification and stabilization of water occurs.
Here, the stream is divided into two parts: crystal-clear water and a concentrated solution discharged into the sewer system. Pure, boiling-free water enters the storage tank, and then through a separate tap to the consumer.
Only the reverse osmotic system is able to provide perfect fine water purification, but the result of their work depends on many factors
The system is designed so that as the flow of purified water, its reserves are replenished automatically. From the inside, the tank consists of 2 chambers, with a silicone membrane as a partition between them. Water enters the upper compartment, and compressed air is located in the lower compartment.
When the volume of water decreases, the membrane expands, maintaining pressure until the water is completely drained. The air pressure can be adjusted by means of a nipple mounted on the side of the lower chamber.
For individual selection of drinking water, a special faucet is cut into the countertop or kitchen sink, which does not depend on the flow that is used for other purposes.
Some manufacturers provide their products with additional functionality:
- mineralizerintroducing useful trace elements into the water that the membrane has not missed;
- ultraviolet lampkilling harmful microbes;
- structuralistrelieving water from "negative" information.
Water consumption during such cleaning cannot be called economical - upon receipt of 1 liter of potable water, 3 liters of dirty water go into the sewer. For the system to work, pressure is required within 2-6 bar, so sometimes it needs to be increased with a pump or lowered using a gearbox.
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Reverse Osmosis Membrane Filter
Filter membrane structure
Module for installing a membrane filter
Hole at the bottom of the module for the membrane filter
Filter system selection criteria
The cost of reverse osmosis filters is quite high. Their choice must be approached responsibly, having previously assessed their capabilities financially, both for the moment and for the future, given the need for periodic replacement of modules.
It should also be understood that most filters purify water very slowly. The speed of water passage depends on the pressure in the water supply, the concentration of various impurities in the water, and the permeability of the membrane. Count on their great performance is not worth it.
In nature, there are no mechanisms that neutralize water from a huge number of toxic elements that enter it from contaminated sources. Therefore, a better alternative than a reverse osmosis system does not yet exist.
So how do you choose a reverse osmosis filter?
The best choice will help to make an assessment according to the following criteria:
- The number of cleaning steps. They can be from 3 to 9.
- The presence of additional functionality.
- The authority of the manufacturer.
- Material and number of stages of prefilters. Plastic should not be odorless. Checking its presence is easy, you just have to unwind the flask.
- Reliability of seals on flasks and connecting elements. The first should be double, and products from JohnGuest and Organic are considered the best compounds.
- The material from which the storage tank and the mounting plate are made.
- Membrane performance.
- The presence of a pump.
- Displacement of the tank.
- Resource membranes and cartridges.
- Type of flask. Cartridges of the “block module” type are more expensive than the “bulb-filler” cartridges, but their replacement is easier. A flask installed in a glass in an internal way is considered to be of higher quality.
- Correspondence of the dimensions of the structure to the availability of free space under the sink.
Of considerable importance is the design of the crane. There may be 1 valve for purified water or 2 if a mineralizer is included in the system.
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All components of the reverse osmosis system are located in plastic flask modules, in which replaceable filter components are installed
The size and shape of the flasks correspond to the size of the replaceable cartridges that perform the function assigned to them and the cleaning level
Replaceable cartridges made of foamed polyethylene with porosity of 5 microns and 1 micron, as well as from pressed activated carbon, are installed in modules for coarse and fine filters
To replace the filter components, it is advisable to buy cartridges of the company that made the cleaning system, or elements with equal sizes
Cartridges are replaced in the simplest way - the lower part of the module is unscrewed with a plastic key, into which a new filter element is then installed
When replacing cartridges, do not interchange filter elements. Each must be installed in the order in which it is cleaned.
At intervals declared by the system manufacturer, the contents of the fifth activated carbon filter must be changed
If the system has a module with a mineralizer, then you do not need to change its contents, but you need to periodically rinse the filler in running water
Component Interchangeability Principle
Matching flask size to cartridges
Coarse and fine filter flasks
Replaceable cartridges for reverse osmosis
Unscrew the flask to replace the cartridge
Installing the cartridge in a clear order
Replacing the carbon filter fill
Mineralizer Module Content
The quality indicator is the color of the bulb. Its surface should be white or matte without streaks and impurities. A fully transparent bulb has very thin walls, and under the influence of high pressure they can simply break.
Often unscrupulous manufacturers use a trick such as increasing the weight of the flask, masking this flaw in the material. It produces an unpleasant odor. A good bulb should be neither very heavy nor too light.
A reverse osmosis filter is a great option, but there are some nuances you should know when choosing a model.
Cases made from quality raw materials can withstand high pressure. They have smooth inner walls without the slightest hint of pores. Bacteria and particulate matter cannot penetrate such a surface. When using secondary raw materials, then microcracks are observed on the surface of the body, sometimes leading to splits.
Manufacturers use plastic or metal to make the tank. The latter is characterized by a longer service life, and the first does not rust.
When choosing, you need to proceed from the operating conditions of the cleaning system. For an apartment or a house where they live permanently, a model made of plastic is suitable, but for giving it is better to choose a tank made of metal. The volume of tanks of different models ranges from 4-12 liters.
Membranes for reverse osmosis filters are produced by many manufacturers. The cheapest are Chinese products. They are distinguished by a small resource and lower than average quality.
The most popular are membrane membranes Filmtec, Osmonics, Pentair, manufactured under license from the United States and TFC from a manufacturer from South Korea. Under normal pressure in the system, they serve 2.5-5 years.
The operation of the system depends not only on the quality of the membrane, but also on what fittings were used during assembly
So, the following basic characteristics are especially important when choosing: the number of stages, the presence of additional cartridges and their service life, the presence of a pump, design dimensions, and performance.
Rating of the best systems for water purification
The range of household reverse osmosis filters is represented by a huge number of offers from different brands. Not all of them are worthy of attention. When choosing a filter for washing, you should pay attention to the manufacturer, user reviews, the duration of his stay in the domestic market.
In order not to doubt the quality of the purchased system, you can compare your choice with the rating of popular filters from professionals involved in the installation and maintenance of reverse osmosis water systems for a long period. The most popular brands include: Atoll, Leader Standart, Aquaphor, New Water, Barrier, Geyser.
Place # 1. Water filter from Atoll
This is a compact model with a 5-stage cleaning system. It is possible to install the tank in a separate cabinet with a lack of free space under the sink.
When replacing cartridges, you do not need to turn off the tap, tank and the system itself from the sewer. The membrane productivity of the household model is sufficient for the needs of a family of 3-4 people.
Water after passing through the membrane enters the storage tank, where it accumulates until it is supplied to the consumer. Thus, the filter is aimed at the preparation of water "for future use"
A membrane of high quality polymer material is produced in the USA. The design of the system is simple and affordable cost of maintenance.
The filter is insured against leakage by the excellent build quality and the fact that it uses John Guest fittings, the reliability of which has long been recognized in the world. The manufacturer comes with a designer crane for each model.
The membrane, which includes several layers, will not miss the smallest pollution.Only water molecules can pass through it.
For the effective operation of the Atoll reverse osmosis system, the pressure in the water supply system must be maintained at a level of 3 to 8 atm. If the upper limit is exceeded, a failure in operation may follow, a pressure reducing valve is necessary to prevent such cases. Pressure below 3 atm also leads to malfunctions if a structure without a pump is installed.
Place # 2. Leader Standart Filters
Leader Standart drinking systems are of high quality. They are produced in Poland and Korea.
Some filter models include a bioceramic cartridge, inside of which are sealed clay balls with the addition of tourmaline minerals. Their value is that they are long infrared waves that change the structure of water and give it healing properties.
All Leader Standart systems work silently, easy to maintain. Leak-proof fittings provided by John Guest
Water passing through these reverse osmosis filters is purified at 97-99%. The manufacturer gives a guarantee for perfect work for 36 months.
Place # 3. Compact filter Aquaphor Morion
A relatively inexpensive and ergonomic filter, operating on the principle of reverse osmosis, created the company Aquaphor.
The device is equipped with a storage tank with a capacity of 5 l, built-in into the body, 3 replaceable modules, a module with a membrane, a set of tubes for connection, taps - inlet and for purified water, a sleeve for connecting the system to the sewer.
Aquaphor Morion is a filter with natural minerals that has an increased filtration rate. It not only cleans, but also softens the water, reliably protects it from bacteria
The first of the modules with a polypropylene filter performs mechanical pretreatment. Replace it with a frequency of 3 months. Deep purification is performed by a second module containing sorbents in the form of fibers and granules. With its help, heavy metals, organics, active chlorine are removed from the water. The frequency of replacement is every six months.
The membrane module is designed for ultra-deep cleaning. Passing through it, water is freed from bacteria, viruses, harmful impurities, nitrites, nitrates, salts, which give it rigidity.
Change this module every one and a half to two years. Final purification and mineralization of water takes place on the fourth module, which is subject to annual replacement.
Place # 4. Installation "New Water"
In addition to the reverse osmosis filter, the system is equipped with a mineralizer and bioceramic activator. New filter modifications from the New Water company are called smart systems. They are characterized by increased productivity, an unusual crane design, which has an LED indicator that responds to a hand brought to the body.
One of the new developments of the company is a full automatic, high-tech 6-speed system. It works on electronic control, equipped with a display, electric pump, electronic pressure sensors and valves. If the membrane becomes dirty, the electronic controller sets a special mode and flushes it.
In the photo, cartridges for the reverse osmosis system "New Water". Models are available in two ranges: Expert and Praktic. They are ergonomic and have a beautiful design.
The design of the filter includes a post-filter mineralizer with a silicon-schungite filler, enriching water with ions of potassium, calcium, magnesium, sodium, which increases its biological value. A storage metal tank holds 12 liters of water. Membrane productivity - 185 liters in 24 hours.
Place # 5. Reverse osmosis system "Osmo 100 Barrier"
The performance of this system is 228 liters per day. At a working pressure of 3 to 7 atm, the water goes through 5 stages of purification:
- “PROFILE BARRIER Mechanics 5 microns” holds solid particles larger than 5 microns. Inside the filter is food grade sprayed polypropylene.
- "BARRIER PROFI Sorption" purifies organics, chlorine, organochlorine compounds. Filler - activated coconut charcoal in granules.
- “PROFILE BARRIER Mechanics 1 micron” is the last preliminary stage of cleaning in front of the membrane when fine suspensions are screened out.
- "BARRIER PROFI Osmo" is the main stage of cleaning. The membrane is made of ultra-thin composite polyamide.
- "BARRIER PROFI Postfilter", where coal enriched with silver is placed. Additionally cleans and enriches the water after the storage tank.
Membrane replacement is performed once every 1.5 years, and mechanical cleaning modules - once a year. The capacity of the plastic tank of the Osmo 100 Barrier filter is 8 liters.
"Barrier Profi Standard" will work even at a pressure in the system of 1.2 atm. Therefore, it is so popular among consumers.
A Russian company produces a filter, so its cost is lower than its foreign counterparts. Consumers do not complain about quality. The body of filters from the Barrier company is very strong. All filter elements are of decent quality.
Place # 6. The filter under a sink "Geyser Prestige"
Three stages of cleaning allow you to retain heavy metals, chloride salts, bacteria, viruses. The performance of the cartridges is 0.13 liters per minute. A feature of the development of the Geyser company is a sorption device, which can only be purchased directly from the manufacturer.
The membrane throughput is 0.0001 microns, it allows you to purify water at the ion level. Change it 1 time in 1.5 years. The pressure required for the operation of the system is at least 3 atm. Under the name "Geyser Prestige" hides how many models, distinguish them by additional characters.
The letter M in the name indicates that there is a mineralizer in the base set, P indicates the presence of a pump, PM - there is a pump and a mineralizer in the set.
The Geyser company in the Geyser Prestige 2 model replaced the 3-stage cleaning system with a special pre-filtering unit. The filter is equipped with a high-quality and efficient Wontron membrane. Now the storage tank can not be used
The number 2 is present in the designation of compact systems with reverse osmosis. If the marking has the number 3, then the system has increased performance.
Filter Recommendations
In addition to the quality of the system itself, the service life and the timeliness of the replacement of individual elements also affect the service life. The main condition for a long and uninterrupted operation of the system is optimal pressure. If it is in the range of 4-6 atm, then the membrane works clearly, and the ratio between clean and dirty water is 1: 2 or 1: 3.
With a decrease in pressure, the force for forcing water through the membrane is not enough and a larger volume of water goes into the sewer, and the resource of the membrane itself decreases.
Reverse osmotic systems are the best option to solve the problem of obtaining truly pure water, but subject to proper installation and timely replacement of the main elements
Other side effects also arise: pre-treatment cartridges become quickly contaminated, the storage tank does not fill up completely, irrational water consumption increases, and the filters in the housings are intensively silted.
You can recognize malfunctions in the reverse osmosis system by the following signs:
- Continuous murmur of water, indicating that water is discharged into the drainage continuously.
- An increase in the meter reading by 2-3 m3 per month from the usual.
- Contamination of primary cartridges for 2-3 months.
- A one-time drain from the storage tank in a volume of less than 7 l or a complete lack of water in it.
- No water flow through the open tap when the tank is full.
- The appearance of scale in the kettle and the water tastes salty.
- Extraneous sounds in the form of clatter when the pump is running, indicating frequent turning the pump on and off.
- The pump does not turn on.
- When the tank is full, the pump does not turn off and it is very hot.
- A hot power supply while the pump does not turn on.
- The water supply is turned off and the pump is running.
Improperly functioning filters form a negative opinion among consumers regarding some good filtering systems. And sometimes you can correct the situation by simply installing a boost pump if the pressure is below 3 atm.
In order to fully understand the specifics of reverse osmosis filters and study the rating of manufacturers of water purification devices, we offer a selection of rollers.
Video # 1. Familiarity with the principle of the double osmosis filter:
Video # 2. Recommendations for choosing a filter for the preparation of drinking water:
Video # 3. Instruction for those who wish to independently install reverse osmosis filters:
Of all reverse osmosis systems, one cannot be unambiguously distinguished and said that it is the best. Their parameters are determined by the throughput of the membrane, the volume of the tank. It is believed that for good water quality, quite 3 cleaning steps are sufficient. And the choice depends on the individual needs of each.
Do you want to share only the well-known subtleties of selecting filters for installation in a reverse osmosis system? Are there any recommendations for using the drinking water treatment system or have questions? Please write comments.