Reverse Osmosis Water Purifier

This device uses the reverse osmosis method to remove about 95 to 99 percent of the chemicals and salts in the water and is easily installed under the sink with a separate drinking water tap.

A water filter only removes large particles and impurities in the water, such as mud, sand, and rust from pipes, while reverse osmosis, by using a semi-permeable membrane, not only removes particles mixed in the water, but also removes all chemicals and microbial, viral, and other contaminants dissolved in the water.

What is a membrane?

A membrane is made up of several thin layers or sheets of film (thin film composite) that are compressed together and spirally wrapped around a plastic tube. The materials that make up the membrane are semi-permeable or semi-permeable materials that prevent the passage of chemical contaminants and undesirable salts, and even viruses and bacteria, so that the impurities are directed out through the membrane wastewater outlet and only water passes through these membranes. The membrane has the ability to remove unsuitable salts in water down to 0.0001 microns in size, thus obtaining clean water.

Osmosis and Reverse Osmosis

If we place a semi-permeable curtain or layer between two liquids that are the same in type but different in density or concentration, for example, pure water and salt water, the system naturally moves towards the equilibrium of the total density, so pure water begins to penetrate through the membrane to lower the density of the salt water. This process is called osmosis.

In the reverse osmosis method, by applying pressure to a highly saline (concentrated) liquid, we reverse the natural flow direction of the osmotic state, so that as a result of the pump pressure on the concentrated liquid, the salts that are not allowed to pass through the semi-permeable layer. Then, pure water passes through the membrane and goes to the other side (more dilute), and thus pure water is obtained.

Function of the reverse osmosis system in water purification devices

The incoming water from the plumbing first enters the first-stage filter, and given that the pores of this filter are about 5 microns (it varies in different devices), it prevents the passage of larger impurities such as mud, sand, and pipe rust. Then, the water enters the second-stage filter, and about 98 percent of organic chemicals and chlorine compounds are separated from the water, and then the water enters the third-stage filter, which prevents the passage of many chemicals, dyes, toxic substances, and chlorine compounds dissolved in water. Then, in the fourth stage, the water enters the membrane filter, which removes about 95 to 99 percent of the very small water-soluble contaminants, such as viruses, microbes, parasites, bacteria, salt, etc., and sends them out of the sewage system of the device, and the purified water enters the pressurized tank, where the water is stored for consumption.

When we open the drinking water tap installed on the sink to remove water, the fifth stage of filtering (post-carbon or linear carbon filter) is performed, in which the water is removed from the pressurized tank and passes through this filter to reach the drinking water tap. During this process, the activated carbon in the filter removes unpleasant tastes and odors from the water. In 6-stage devices, there is also another filter, which can be a mineral filter or, in some cases, an ORP filter.

Mineral filter in a home water purifier

The mineral filter complements the fourth stage and helps improve the taste and smell of the outgoing water with the minerals in the filter. The ORP filter is responsible for raising the pH of the outgoing water. As we know, water is suitable for drinking if its pH is above 7 and around 7.5. ORP filters take care of this operation.

Ultraviolet water disinfection

A filter called an ultraviolet (UV) water disinfection filter is also available in 7-stage devices. This filter consists of a steel or, in some cases, plastic container with a UV lamp inside. By irradiating the water with UV rays, 100% disinfection is achieved in the water. These devices are used more in places where chlorination has not been done in the water or the risk of water contamination is very high.

Removal of salt elements by reverse osmosis system

The reverse osmosis system was originally designed for the Navy to desalinate sea water. Because sea water is rich in sodium and its compounds, which table salt is also one of them. For those who want a low-sodium diet, the water of this device is very suitable. Basically, this is why these devices are usually called desalinators.

Removing bacteria, viruses and microbes by reverse osmosis system

The pores of the membrane are much smaller than the diameter of bacteria, parasites and viruses, and do not allow them to pass through and remove them from the sewage of the device. Of course, it is better to use a disinfection system as a complement to this device in cases where the probability of microbial, viral or bacterial contamination of the water is very high to ensure 100%.

The taste of the purified water of this system, given that it removes a lot of salt salts from the water, may seem bitter in some cases at first, when the family's taste is not used to it, but this does not seem to be the case after a few days of using purified water. Of course, if you wish, you can completely eliminate this slight taste at the beginning of installation by adjusting the device.

Removing toxins dissolved in drinking water from the body

Here is a discussion about the pros and cons. Most of the minerals we need are absorbed by the body through food and vegetables, and a small amount is absorbed through water. We can easily provide the minerals we need with replacement substances, but if toxic substances enter our body, we will no longer be able to remove them. There is no substitute for the body.

Types of drinking water taps for water purifiers

These devices are usually installed under the sink, with their outlet connected to a drinking water tap that is placed on the sink, and there is also the possibility of branching to connect water to refrigerators that have a water inlet (side-by-side), but there are also other types such as cabinet, wall-mounted, coleman, case, etc.

A beautiful and elegant drinking water tap (depending on the model of the device) is installed on the sink, which is called a drinking water tap, all family needs for drinking and cooking should be done from now on with this tap that contains purified water.

Factors affecting the quality of the output water

Three main factors affect the quality and amount of purified water production:

1. Pressure: The higher the water pressure (which the device pump provides), the better and greater the quality and amount of water produced. A pressure of 60 P.S.I. is ideal.
2. Temperature: 24°C is the ideal temperature for an RO device. If the temperature reaches 4°C, RO production will be halved. The maximum operating temperature of the devices is 29°C, so it is better to place them in a place where the normal temperature is available for the device.
3. Total Dissolved Solids (T.D.S): As the amount of dissolved solids in water increases, the amount of water produced by the device decreases. High T.D.S can be compensated by double pressure.

Amount of water purification by home water purifiers

Depending on their filters, home water purifiers can produce from 50 gallons (approximately 150 liters) to 100 gallons (approximately 300 liters) of water per day. Capacities higher than this amount, from 300 to 600 gallons per day, are classified as semi-industrial or office devices, and from 800 gallons and above, they are classified as industrial devices that are ready-made packages or are made specifically to order.

Home water purifier warranty

If water purifiers are manufactured by reputable companies, they usually have a warranty of at least one year, and in the event of water leakage and damage, their parts (except for the filters, which are consumables) are replaced or serviced free of charge.

When should we replace home water purifier filters?

If the filters of the device are replaced at the specified times, these systems do not require special maintenance, and the replacement of the filters can be done by the person himself or, if requested, by water purification experts. When the amount of water output of the device decreases significantly or the taste of the water changes noticeably and returns to its original state, the membrane filter should be replaced. Of course, the health or unhealthiness of the membrane can also be determined by the TDS test.