Pros and cons of reverse osmosis

Pros and Cons of Reverse Osmosis: What You Need To Know

Table of Contents
Table of Contents

Ensuring you are drinking quality water means your body stays hydrated and functions properly. Although people often rely on tap water and private wells for their drinking water, it may not be entirely safe to drink.

City water may have chemicals to treat the water, but those very same chemicals may be harmful in high doses. And well water may contain heavy metals and bacteria that need to be removed before drinking.

Fortunately, there are ways to treat water through modern filtration systems safely. Reverse Osmosis water filters can not only treat well water and city water, but it can also treat seawater, river water, and rainwater.

In this blog post, we will cover the pros and cons of reverse osmosis (RO) and everything you need to know about RO filtration systems.

Related Article: How to Test For Heavy Metals in Water

Related Article: How to Purify River Water For Drinking 

Related Article: How to Filter Rainwater at Home

reverse osmosis

What is Reverse Osmosis Water Filtration?

Reverse osmosis is inspired by the principle of osmosis.

It works by using pressure to push untreated water into entering the tiny pores of the membrane as it moves from the less concentrated side to the more concentrated side of the RO system. Two separate solutions flow in both directions entering the membrane until equilibrium is achieved. As the water passes through the membranes, solid particles like sediments and salts are left behind

In reverse osmosis, the untreated water is forced by pressure to enter the semi-permeable membrane, flowing from the more concentrated side, like seawater, to the less concentrated side, where the treated water is.

The treated water is then collected in a container for water-keeping and usage control. The contaminants that are rejected by the membrane are then washed away as wastewater. 

Reverse osmosis is an effective water filtration method that can purify a contaminated or polluted water source, thus converting untreated water into potable water that is safe for drinking, cleaning, and cooking. It is effective in removing dissolved chemicals, sediments, and microorganisms such as bacteria and viruses, including Giardia and Cryptosporidium.

Additionally, it can also remove heavy metals that are harmful to health when consumed and removes any chlorine that affects the taste of your water.

how reverse osmosis works

How does a Reverse Osmosis Filter Work?

Below are the specific stages of understanding how reverse osmosis water filtration works in treating seawater.

  1. A pre-filter is used to remove sediments from the untreated water before proceeding to the main reverse osmosis membrane. Pretreatment ensures that impurities and solid particles are eliminated first, as they may clog and damage the RO membrane during the process.
  2. Next, the pre-filtered water enters the microscopic pores of the RO membrane, resulting in the removal of impurities, contaminants, and microorganisms. A high-pressure pump is needed to force the more concentrated side to flow to the less concentrated side until equilibrium is attained.
  3. After passing through the membrane, water flows to the water storage location, where it is kept until needed. When the water storage is full, the reverse osmosis system will also stop filtering water.
  4. Before the treated water in the storage tank travels toward your faucet, water passes through a post-filter to further treat and enhance the drinking water. The product water’s taste may change due to the removed minerals during the process, including the beneficial minerals. To restore the lost beneficial minerals, a remineralizer will be needed.

river water for drinking

Advantages of a Reverse Osmosis Water Filter

Below are some of the many advantages of reverse osmosis water filters:

  • Turns seawater into potable water: Seawater is the most abundant source of water on the planet. Unlike other filtration systems, RO systems can turn ocean water or seawater into potable water that can be used for drinking, cooking, and showering. 
  • High Effectivity Rate: Reverse osmosis removes 95% to 99% of dissolved solids that is present in hard water or polluted water source. Additionally, it also removes larger compounds like sediments, sand, or salts and even microorganisms like bacteria and viruses. 
  • Effective Water Softener: Water sources like lakes, rivers, and private wells commonly have attributes of hard water which is not ideal for drinking purposes. The presence of heavy metals, particularly, Calcium and Magnesium, makes the water “hard.” To make it soft, water filters like reverse osmosis are used to remove harmful heavy metals in the water. 
  • Comes with Multi-layer Filters: The reverse osmosis system is composed of different stages of filters, with each serving a different purposes. The first-in-the-line filters usually aim to pre-filter and eliminate the larger compounds and solid particles of the raw water before proceeding to the main RO membrane. 
  • Safe Household Water Supply: Reverse osmosis is a whole-house water filter system which means it is capable of filtering the water supply of your entire household that runs through your distribution pipes and up until your water faucet control.
  • Easy Maintenance: Maintenance of the reverse osmosis system can be simple, especially the reverse osmosis for household use, which is small in size. Regular cleaning of the reverse osmosis filter will prevent early deterioration of your RO system, and it can be done by only using natural cleaners like vinegar which can be found at your home. 
  • Improves the Taste and Odor of Water: After going through the multi-layer filters, the RO membrane, and a post filter, the product water that the reverse osmosis system treated provides quality water with adequate taste and odor. Thus, the treated water becomes desirable to drink. To even improve the taste of the product water, you may use a remineralizer.

river water for showering

Disadvantages of Reverse Osmosis Water Filter

Below are some of the disadvantages of reverse osmosis water filters:

  • Pre-filtration is Required: In order to prevent bacterial growth and premature deterioration of the filter’s membrane, prefiltration of the feed water is needed. Prefiltration is performed to prevent clogging issues and ensure that large compounds like sediments, sands, and salts are eliminated first. Once the pre-filtered water enters the reverse osmosis system, this eases the flow of concentrated water in passing through the tiny pores of the membrane. 
  • Beneficial Minerals are Removed: With the high efficacy rate of reverse osmosis, the beneficial minerals present in the water are also removed. The removal of all the minerals affects the taste of the treated water. To restore the removed minerals, use a remineralizer to reintegrate the necessary healthy minerals in the water. 
  • Membranes Prone to Clogging: The continuous operations of the reverse osmosis system and the flow of feed water or concentrated water into the system may result in clogging issues. Without initial filtration treatment, the membrane may clog due to the solid particles that accumulate within the microscopic pores of the membrane. 
  • Slow Filtration Time: A reverse osmosis filter is one of the best options to purify and soften polluted water because of the power of the tiny pores of the membrane. However, high water pressure is needed to force the concentrated water to pass through these tiny pores, which causes the slow filtration flow of water. Thus, filling the storage tank will require a longer waiting time if you use reverse osmosis to cater to your household water needs. 
  • Disinfection Needed: If prefiltration is required before allowing the feed water to enter the reverse osmosis membrane, disinfection is also required after the treatment of the system. Regular filter backwashing and routine membrane cleaning are needed to prevent membrane fouling and bacterial growth within the membrane pores, especially during the temporary shutdown of the equipment. Doing this will help prevent premature deterioration and permanent damage to the equipment. 
  • RO System Wastes Water: RO units use a lot of water. They recover only a certain percentage of the water entering the system. The excess is discharged as wastewater. However, in the case of a household reverse osmosis system, the amount of wastewater can be small compared to other sources since the water is used for drinking, cooking, and showering only.

Alternatives to Reverse Osmosis Filtration Systems

Despite all the benefits of RO filter systems, they are not the only filtration system available. Below are some alternatives to RO filters.

1) Ultraviolet (UV) Light Filtration System

uv light water treatmentUV light filters use ultraviolet light to disrupt the DNA of harmful pathogens, making them ineffective in spreading disease. This method actually mimics the natural antibacterial properties of the sun. Since this method relies on UV light, it is a chemical-free treatment system.

By placing the UV light bulb in uncloudy water, the light will spread throughout the water, killing many of the harmful pathogens. UV water filters can come in the form of a water bottle or be able to treat an entire home.

The main drawbacks of using this system are that it won’t function well in cloudy water, nor can it be used to treat sediments, heavy metals, or chemicals. To remove other contaminants, you will need an additional water filtration system. 

Related Article: UV Water Filters Pros and Cons: Everything You Need To Know

2) Quantum Disinfection Water Filtration System

quantum disinfection water filterQuantum Disinfection is a new disinfection technology that kills harmful bacteria by using the principles of quantum mechanics. This method kills bacteria without the use of chemicals or electricity, posing a lower risk to humans and the environment.

This system makes use of a series of beads, and each has a small catalytic site on the surface. Electrons are drawn from bacteria to the catalytic sites as water passes over the surface of the beads.

Related Article: What is a Quantum Disinfection Water Filter and How Does It Work?

3) Solar Purification

solar purifierSolar purification is the process of treating water by exposing water to the direct heat of sunlight. Glass bottles are filled with water and placed under the sun for at least 6 hours.

However, it is important to know that this method does not work during cloudy days. Additionally, this method is ineffective against large amounts of water.

Related Article: Solar Purification: How To Purify Water Using Solar Energy

4) Gravity Filters

ceramic water filterGravity water filters use the force of gravity to push untreated water through filter cartridges. Gravity filters are typically made from ceramic, stainless steel, or plastic. Water passes through microscopic filters, which are effective at removing solid particles and microorganisms.

However, it does not remove other contaminants, such as toxins or other heavy metals. It requires advanced filtration cartridges or an additional filtration system to remove chemicals and heavy metals from the water. 

Related Article: Pros and Cons of Ceramic Water Filters

Related Article: Brazilian Clay Water Filters: Everything You Need to Know

Final Thoughts

All in all, RO water filters are highly effective water filtration systems. They remove harmful pathogens, minerals, heavy metals, and chemical contaminants, leaving behind only water molecules to make pure water. The RO process may leave the treated water flavorless and odorless, but you can add back healthy minerals by remineralizing the water.

One of the main downsides of this system is that it does generate water waste. However, this is a necessary process to remove any non-water contaminants. To make truly fresh water, having a RO system is one of the best filtration systems to have at home.

People Also Asked

Some questions people ask frequently are:

Do reverse osmosis systems waste water?

Yes. The reverse osmosis system wastes a lot of water during the filtration process. It does not completely filter and treat the entire feed water that is hoped to be purified. Instead, it treats and recovers only a certain percentage of the raw water entering the system. The excess is then discharged as wastewater.

Do reverse osmosis filters remove fluoride?

Yes. The major purpose of reverse osmosis filtration is to remove dissolved contaminants, microorganisms, and heavy metals like fluoride, which are present in groundwater, private wells, and surface water. The RO membrane and extra filters offered by reverse osmosis are designed to effectively soften hard water and purify untreated water.

Do reverse osmosis filters remove minerals?

Yes. Beneficial minerals are also removed during the process of filtration, which demineralizes the product water. To restore the removed healthy minerals and improve the taste of treated water, a remineralizer would be necessary.

Can reverse osmosis remove lead?

Yes. Lead is a heavy metal typically found in contaminated groundwater, private wells, or surface water. Heavy metals like lead are one of the factors which make a water source “hard” and not ideal for drinking purposes. Exposure to lead can impact your health and cause a variety of diseases.

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