Membrane filter for water purification

Bad water from the tap is the scourge of the inhabitants of big cities. Even after boiling, it leaves an unpleasant aftertaste in the mouth. In addition, some experts argue that even boiling can not clean it from harmful impurities and germs. If you live in an apartment and suffer from poor water, a membrane filter for water treatment will help you.

What is a membrane filter?

All filters perform the function of trapping harmful impurities. At the exit, we get tasty water that you can boil or drink immediately. The membrane system, operating on the principle of reverse osmosis, does not allow any harmful substances to pass through, does not accumulate them in itself, and, due to its design, flushes it into the drainage. It has pores through which only water and oxygen can pass. There are several types of materials for the production of such a filter: lavsan, polyurethane and others.

The first such systems were invented back in the 19th century, but the prototype of a modern membrane was not released until the 1960s. It is believed that these are the best systems for water purification of all existing. They trap not only large debris, but also small particles, purifying water at the molecular level.

All large Russian and foreign companies for the manufacture of water filters have membrane designs in their assortment. First of all, they are in demand among residents of apartments in large cities.

Externally, the device is a plastic cylindrical box, inside of which is a membrane and one or more prefilters. It is connected to cold water and discharged to the sink by a separate tap. Each filter has its own service life, as over time it becomes dirty and cannot perform its functions.

The principle of the reverse osmosis membrane

The reverse osmosis membrane is made of special materials that can only pass water molecules and oxygen, all other substances, do not accumulate, but merge into a drainage stream of water.

The filter itself has one entrance for water from the water supply and two exits. The fact is that water is divided into two streams: one leaves purified, and the second flushes impurities from the membrane and carries them to the sewer.

There are membrane filters that work differently. They are placed in a container of water, it passes through the membrane and, on the principle of communicating vessels, comes out purified. The use of such a filter is justified in field conditions when there is no water supply nearby.

In the field filter, it is necessary to clean the membrane cartridges from time to time. You can rinse them with clean water or use special chemicals. They are selected depending on the type of contamination. Acidic removes salts well, and alkaline - organic and biological compounds.

Membrane Varieties

There are several types of membrane filtering systems. They differ in type of construction and pore size. Filters with small openings are considered the best, since they clean water well.

Membrane Types:

1. Microfiltration. Provides rough water purification, used in the preparatory phase. Such a filter will cope with muddy wastewater, but in the future it will require finer cleaning.
2. Ultrafiltrational. This type of membrane can purify water from macromolecular compounds, bacteria. It is usually used in industrial enterprises, as it does not remove salt from the water.
3. Nanofiltration. Well suited for hard domestic water. In addition to bacteria, removes impurities of chlorine and heavy metals from water.
4. Reverse osmosis membrane. Such a system has the smallest openings and retains all substances and contaminants harmful to humans. 98% neutralize salts, bacteria, viruses, oil products. With the help of such filters it is possible to purify and desalinate sea water, they are used in the production of bottled water, in pharmacology and microbiology.

Views by type of construction

By design type, filters are divided into:

• Tubular. The cleaning element is a porous tube. They can be made of cermets, plastics, ceramics. The diameter of the pipe can reach up to several centimeters. Symmetric and asymmetric membranes exist. In the first, the pores are evenly distributed; in the second, one wall has a larger concentration of holes than the other. Water is supplied under pressure into this pipe, and the output is a clean liquid, and in a separate container - a concentrate of harmful substances.

• Roll. This filter is a membrane wound, like a roll, on the main pipe. Through a special hole, water enters it and flows in a spiral, while being cleaned. Pure water flows down the main pipe, and harmful substances come out of another hole. Such systems are cheap to manufacture, but are quickly contaminated during operation.
• Hollow fiber. They consist of membrane tubes, which are placed in the apparatus for filtration. This significantly increases the working surface, but such filters are quickly clogged and difficult to clean.

• Disk. They have only laboratory use and are not used to purify water in a drinking house. The filter element is made in the form of a flat disk. The principle of operation of this design is that water is poured into the tank in which the piston with the membrane runs. It can be compared with a household French press. Only the filter has several pistons to increase the amount of filtered water. Pure water goes to the tap to the consumer, and harmful substances settle in a special tank.

Types of disk membranes:

1. Ordinary - consist of one substance.
2. Reinforced - consist of a fabric substrate with porous material on top.
3. Subligamentous - consist of large-porous material (for example, polysulfone) and a working layer (polystyrene).

Do not worry that all layers of the disk are of chemical origin, the use of such a filter is absolutely safe for health.

Advantages and disadvantages

Compared to other types of filter systems, the membrane design has the following advantages:

• Easy operation and maintenance.
• Good degree of cleaning.
• The small sizes.
• The presence of hiking varieties.

Many families have appreciated the benefits of a membrane filter. It allows you to take care of the health of loved ones without unnecessary trouble. Parents who think about the future of their children most often choose membrane systems for water treatment.

But this design has its drawbacks:

• High price.
• May delay beneficial substances.
• Weak water flow from the filter.

He copes well with the last flaw reverse osmosis filter Atoll A-3800p STD. Its performance reaches two liters per minute, so it does not require a storage tank. The device uses two Atoll TW 30-3012-400 membranes and their productivity is so great that this installation is capable of providing a family of 6 people with water for 30 months. And at the same time, it is compact and not whimsical to pressure, since it has its own pump.

Membrane water filter - This is an excellent choice for residents of cities that are dissatisfied with the quality of tap water. Some families order delivery of clean water from special companies, but you can drink tap water if you clean it first. The membrane design is considered one of the best to date.