Understand The Reverse Osmosis Process (We Detailed For You)

 Last updated  - November 19th, 2021

Everybody knows that drinking the proper amount of water is important to our health. Yet, how well are you monitoring the water that we put into our bodies? How much do you know about water purification and the different ways to remove bacteria in your water. Here, we will be discussing what is reverse osmosis? How does it work for household use?

Water Purification Methods

There are many methods of purifying water. Many of those methods are subcategories under the main three.

RO water purification methods for your home

1- Boiling 

Boiling water is the oldest practice of water purification. This method is easy and inexpensive. Bringing water to its boiling point will kill any microorganisms and remove bacteria. Necessary minerals such as calcium and salts will stay.

2- Chemical Purification of Water

A chemical water purification method uses compressed liquefied chlorine gas or its compound in water to remove bacteria. The process uses lead-lined iron vessels and is suitable for large-scale volumes.

Another chemical purification is the process of infusing water with iodine. In general, adding iodine to your beverage can help kill pathogenic bacteria in your water. Yet, iodine-treated water leaves an unfavorable taste and is only meant for short-term use. That is the reason why you can use a carbon filter to remedy this case.

Pregnant women and those with thyroid conditions are not advised to drink treated water.

3- Modern Water Purification Methods

• Filtration 

This method purifies water by allowing water to pass through a combination of filters. These may use layers of sand and gravel. Others may opt for hard coal. The activated carbon water filtration systems can remove heavy toxic chemicals like mercury, lead, arsenic, asbestos, and benzene.

This process has gone a long way in recent years and is now available for home and personal use. Handheld water filters are available which has the convenience of using them for outdoor activities too.

• Reverse Osmosis 

It’s a water purification process that uses a filtration process to purify water from bacteria.

What Is Reverse Osmosis? 

The RO uses a membrane technology filtration method that removes all contaminants from water, including types of huge molecules and ions with the use of pressure.

what is reverse osmosis

This concept reverses the flow of osmosis. The water passes from a more concentrated solution resulting in a more diluted solution after it passes through a semi-permeable RO membrane.

A very popular application for this process is in seawater purification to make it fresh water. A dense solution (seawater) uses reverse osmosis to turn it into its dilute form (freshwater). The pore size of this semi-permeable thin membrane is about 0.0001 micron.

The ultra-fine pores will allow pure water to pass through while preventing larger molecules from doing so. Contaminants are either dissolved salts or other impurities. The pressure is then applied to the concentrated solution when it is on one side of the semi-permeable, thin membrane. The solution then passes through the result on the other side is a pure solvent.

Reverse osmosis results in purified water for drinking water systems and other intended purposes.

The Process of Reverse Osmosis

There are at least 4 stages needed to complete the reverse osmosis process. These include the following: a sediment pre-filter, a carbon block pre-filter, a reverse osmosis membrane, and a carbon block post filter.

reverse osmosis filtration process
Diagram for a 5 Stage Reverse Osmosis Filtration

Understanding 5 stages of Reverse Osmosis Filtration:

Stage 1

Using a valve, a water line is fitted to the water source. In a home setup, the water source may be the public water supply or even water from a well.

The first stage uses a pre-filter to screen out larger solid impurities like sediments and dirt present from the water.

Stage 2 

With the larger solid impurities removed, stage 2 of the process will usually have a carbon filter or another filter of the sort.

As water is processed at this stage, the carbon filter removes chlorine, odors present in the water, sediments, and volatile organic compounds (VOCs). These are other contaminants in the air and other household products which may also be present in water.

Stage 3

The actual process of reverse osmosis takes place.

This is the purification stage where pressure is applied to water as it passes through the fine membranes to produce clean clear water. This stage removes almost all contaminants like total dissolved solids (TDS).

The diagram above shows a cross-section of the tube, the semi-permeable membrane, and porous layers allow filtering as the pressure moves the water through the membrane. This stage removes bacteria as water molecules pass through.

Stage 4

Minerals, salts, and dissolved inorganic substances may still be present as the clean water exits stage 3. Moreover, these impurities may still harm our health and affect the taste of the water.

Therefore, stage 4 does the final removal of harmful substances. After all, the clean water then goes to the water tank reserve.

Stage 5

The last stage is post-filtration. The water leaves the tank. As the water goes to the point of use, it passes through a filtration membrane. The filtration system does a final clean of collection particles coming from the tank.

This stage reduces the contaminants and bacteria in your water by as much as 97%. The RO process removes minerals such as calcium and magnesium. You can also choose to infuse your water with essential minerals.

Systems for Household

RO is a water treatment method that has found application in various fields. Treated water through reverse osmosis is necessary for cosmetics and pharmaceutical production, and many other applications.

reverse osmosis system home

General tap water contains volatile organic compounds (VOCs) such as pesticides and herbicides, heavy metals, endocrine-disrupting chemicals such as fluoride, as well as hormones and parasite cysts. It removes bacteria frome your water supply.

Using reverse osmosis water filtration systems can reduce all these contaminants. Independent studies by private companies show that only 2% of the entire household is used for water consumption. The rest is used for various activities like bathing, washing clothes, and watering for the lawns for instance. Nonetheless, there are still many individuals who prefer to install apparatuses like Aquasana OptimH2O or Waterdrop RO in their households.

It is capable of removing 99% of bacteria from your drinking water. In addition, the membranes can remove viruses and parasites besides the said chemicals, heavy metals, fluoride, herbicides, pesticides, unpleasant odor, and taste.

The other minerals such as Lead, Chlorine, Copper, Cadmium were removed by as much as 95%, resulting in pure water. In conclusion, this superior purifying process provides the highest quality water.


Reverse osmosis is a thorough and powerful means of water filtration.

Many people are still skeptical as the Reverse Osmosis filtration system can be too thorough filtering out even the essential minerals. But a quick fix would be to opt for the RO filter and an extension wherein minerals can be put back in the water.

All in all, Water Filters Advisor confirms this is a great water filtration system for homeowners to be comfortable with their water quality.