Difference Between RO, UV, and UF Water Purifiers

Difference Between RO, UV, and UF Water Purifiers

In today’s time, due to increasing pollution and diseases arising in water, it has become necessary to have a water purifier in every house. A water purifier provides us with clean and pure water to drink. In today’s modern era, there are many options available to purify water.

One of these options is RO Water Purifier which is a more advanced and most used technology. The full form of RO is Reverse Osmosis i.e. Reverse Osmosis.

What is RO?

The full form of RO is Reverse Osmosis and it is a water purification process. In this technology, RO membranes are used to purify water. RO membrane is a very thin membrane-like cloth that has very fine holes. Through this, very small viruses, bacteria, and germs present inside the water, which are not possible to see with the naked eye, are filtered out. This membrane also separates the toxic chemicals present in the water.

Contaminants Removed From Water by RO

A Reverse Osmosis is capable of removing 99%+ contaminants. The RO membrane separates the contaminants on the basis of their size and charge. However, an RO system cannot be trusted to remove 100% of bacteria and viruses. Some of the contaminants that can be removed by the RO system are as follows:

  1. Dissolved Salts
  2. Particles
  3. Colloids
  4. Organics
  5. Bacteria
  6. Viruses

Is RO Purified Water Safe?

RO purified has both merits and demerits, and as it can prevent negative effects on our health, it is not fair to classify it as “more dangerous for us”.

Merits of RO

First of all, let’s talk about its merits. The membrane used in this is a non-chemical and non-residue release a physical process that separates the contaminants from the water. The removal of contaminants depends on the holes in the RO membrane.

Because these holes are small enough (0.22–0.45 µm) to be able to remove almost everything from water and provide us with highly purified water. This water can also be used for surgical and pharmaceutical purposes.

Demerits of RO

If we talk about demerits, we can say that RO demineralizes the water to such an extent where it remains unfit for drinking. Removal of minerals from water can cause deficiency of minerals in our body.

This water does not quench thirst. Long-term use can cause some diseases such as reduced bone density, which can make our bones weak. The pH of the water also decreases, which gives a sour taste. But in cases where there is a risk of carcinogenic elements entering the body, RO acts as a protector.

Advantages of RO Water Purifier

  1. By killing the harmful bacteria and viruses present in the water, it eliminates them completely.
  2. It converts hard water into soft water.
  3. It is very easy to use and maintain RO.
  4. RO removes toxic substances present in water such as heavy metals, salts, mercury, fluoride, arsenic, chlorinee etc.
  5. It provides you with a safe drinking water.

Disadvantages of RO Water Purifier

Removes essential minerals – RO water purifier removes the impurities dissolved in water as well as the natural minerals present in it like iron, magnesium, calcium, and sodium which are essential for the human body. Due to this, there is a shortage of essential minerals in the body.

Bacteria and Viruses do not die – RO water purifier does not kill disease-causing bacteria and viruses in the water. Here there are more chances of these microorganisms passing through the RO membrane, which can enter our body with water (it is recommended to pass RO water with a UV water purifier to destroy these microorganisms).

The taste of water changes – When the natural minerals are removed from the water, the water becomes de-mineralized, due to which the taste of the water changes and becomes pale.

Takes more time to purify – RO water purifier takes more time to purify water.

Water Waste – Wastewater flows more than filters out water.

Expensive – It is more expensive than other purifiers. UV and RO water purifiers consume more electricity.

Rupture of RO membrane – There is no such mechanism that can tell when to replace the RO membrane. The chlorine present in the water can damage the RO membrane. The tiny pores of the RO membrane get clogged by chlorine and there is a drastic reduction in performance. In such a situation the membrane breaks down and the dissolved salts, bacteria, viruses, etc. easily cross the RO membrane. Therefore it is advised to replace the RO membrane after every one year.


Before working on Reverse Osmosis (RO), it is important to know about Osmosis. Osmosis is a natural phenomenon that means the effect of close contact. In this process, the solution containing less salt always tries to migrate towards the solution containing more salt. For example, the absorption of water from the soil by the roots of plants and the absorption of water from the blood of our kidneys is called the osmosis process.

Osmosis example

If you have a container that is filled with low salt concentrated water and another container that is filled with high salt concentrated water and they are separated by a semi-permeable membrane, then water with a low salt concentration is more The salt will start to migrate towards the water container of concentration.

A semi-permeable membrane is a membrane that allows some of the atoms or molecules to pass through and inhibit other molecules. For example, the mesh indoors, allows air molecules to pass through while blocking anything larger than the holes in.

Reverse Osmosis

Reverse Osmosis is the process that reverses osmosis. Where osmosis, being a natural phenomenon, does not require any energy, to reverse the process of osmosis, energy needs to be applied to a more saline solution.

To filter the water in Reverse Osmosis (RO), pressure is applied on the water from one side and it is passed through the membrane. The holes in the membrane are so small that only water molecules can pass through it. Molecules of germs and bacteria are larger than molecules of water which cannot cross the membrane.

An RO membrane is the membrane that allows water molecules to pass through while preventing the passage of salts, bacteria, organics, and harmful chemicals contained in the water. However, you will need to push it from the RO membrane by applying pressure on the water. The pressure applied to the water should always be more than the natural osmosis process so that the pure water can be passed by holding more contaminants present.

How does RO work?

A high-pressure pump is used in Reverse Osmosis. Through this pump, pressure is applied towards the impure water and the water is passed through the RO membrane. Due to the small holes in the membrane, water molecules can pass easily, while harmful substances such as salt (ions), bacteria, or viruses contained in the water, which are larger than the holes in the membrane, are separated along the reject stream.

The pressure applied to impure water depends on the ions present in the water and their concentration. The more concentrated the water, the more pressure will be needed to remove osmotic pressure.

The stream of water that carries with it those concentrated contaminants that could not pass through the RO membrane is called the Reject Stream.

RO working

As the feedwater enters the RO membrane under pressure, the water molecules cross this semi-permeable membrane and the salt and other contaminants that cannot cross this membrane are ejected along the reject stream. This reject stream is drained into the drain or in some circumstances, taking care of saving water, is recycled from the RO system and put back into the feed water supply. The water that comes out of the RO membrane is called permeate or product water and usually, 95% to 99% of the salts are separated from it.

Difference Between RO, UV, and UF Water Purifiers

In this, electricity is needed to purify water in this also electricity is needed to purify water it does not need electricity.
It works with high water pressureIt works with normal water pressureIt can work on any water pressure
It removes the germs from the waterit kills the germs without removing itit filters out the germs.
It separates the salts and harmful metals dissolved in water.It does not separate the salts and harmful metals present in the water.It also does not separate the dissolved salts and metals.
Difference Between RO, UV, and UF Water Purifiers

What is a UV Water Purifier?

A UV water purifier uses ultra-violet rays to kill germs and bacteria. It is the most effective technique to combat water-borne diseases. This prevents bacteria from spreading diseases in the water. This method is very effective, simple, and eco-friendly.

How does a UV Water Purifier Work?

During the UV water purification procedure, water is passed through a UV radiation source tube. Then UV radiations are poured over the water. UV rays are capable of killing disease-causing germs and bacteria. It directly attacks the DNA of these germs and bacteria and prevents them from being born again. Thus it provides us with clean and clean potable water.

Advantages of UV water purifier

  1. This is the most effective way to purify water.
  2. In this method of purifying water, no harmful chemicals or products are used.
  3. Very little energy is used in the purification of water by this method.
  4. UV purifiers are easier to maintain and less time-consuming.

Disadvantages of UV water purifier

  1. It kills the bacteria and viruses present in the water but does not remove the dissolved impurities like pesticides, rust, arsenic, fluoride, etc.
  2. It does not convert hard water into soft water.
  3. UV water purifier always needs electricity. If the electricity cut-off is more in your area and the water purifier does not have a storage tank then If you do not have electricity, there is no source of purified water.
  4. It is not effective on muddy water. If the water is muddy, then first you have to pass this water through some other purifier, then through a UV purifier.
  5. UV rays do not always stay in the water. If UV rays miss a microorganism, this living microorganism will increase its population and will contaminate the water. Therefore, after purifying the water with UV, it is advisable to use chlorine.

READ MORE – What are e-RUPI and its features?

What is a UF Water Purifier?

The full form of UF is “Ultra Filtration”. This is a basic technology that is somewhat similar to an RO water purifier. However, it is not as advanced as RO technology.

Like RO, a UF water purifier also works based on semi-permeable membranes. In this, the holes of the membrane are larger than the holes of the RO membrane. This membrane works to remove contaminants from water molecules.

How does the UF Water Purifier Work?

In this, water is pushed towards the membrane using hydrostatic force. This membrane has small holes through which water molecules can pass, but micro components and germs cannot pass because their size is larger than the size of the water molecules. Hence these impurities get separated from the water and the UF water purifier provides us with pure water to drink.

This purification process is completely natural and no chemicals are used in it. Even electricity is not needed in it.

Advantages of UF water purifier

  1. In this, two basic filters are used to remove the impurities, which are very cheap.
  2. It gives pure water even than boiled water. Because after the death of the bacteria in the boiled water, their body remains in the water, while the UF water purifier separates them.
  3. It works on gravity and natural water pressure, so it does not require electricity.
  4. It can also convert muddy water into clean water.
  5. There is not much material in it and the weight is also less. So it is easy to carry it from one place to another.
  6. Its maintenance cost is very less.
  7. It is very easy to install.
  8. It does not waste water and is eco-friendly.

Disadvantages of UF Water Purifier

The biggest disadvantage of the UF filter is that it does not separate harmful salts and heavy metals dissolved in water. Toxic metalloids like cadmium, arsenic, lead, mercury, etc. cause fatal diseases like cancer. These can be separated from the water only by using an RO water purifier.

How do We Know Which Type of Water Purifier do We Need?

Before buying any water purifier, you must consider some important factors, such as what is the source of your water, what is the type of contamination, what is the TDS value, etc. So let’s know which type of water purifier is suitable for your home.

First of all, you should get the TDS test of your home water done. If you do not know how to do this test and what should be its value, then there is no need to worry, let’s discuss it.

If there is an industry in your area, then you should get a chemical test done and find out the chemical impurities present in the water.

If still, you have any confusion then you can choose the best water purifier with RO + UV + UF technology.

TDS Valuedirty waterbacteriasuitable purifier
Less then 300PPM No   YesUV water purifier
Less then 300PPM Yes YesUV+UF water purifier
Greater then 300PPM No   NoRO water purifier + TDS controller
Greater then 300PPM Yes  YesRO+UV+UF water purifier + TDS controller

NOTE: One thing is worth noting here, the presence of any individual toxic substance in the water is more important than the value of TDS. For example, the total TDS value of your water is less than 300, which is generally considered safe for drinking. However, water may contain high amounts of harmful substances such as arsenic, lead, or mercury.

What is TDS?

TDS stands for Total Dissolved Solids. It shows the total number of dissolved solids in water. The majority of these solids are inorganic salts and some contain organic compounds.

Many inorganic salts are present in water, such as sodium, potassium, magnesium, calcium, etc.

Some heavy metals like arsenic, lead, and mercury is also present in groundwater. These heavy metals are extremely harmful to health and are considered slow poisons i.e. slow poisons.

The high amount of TDS indicates the number of harmful substances present in the water. On the other hand, if the TDS becomes too low, then the water becomes tasteless.

Therefore we should know the correct TDS level of the water used in the house.


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