Reverse Osmosis (RO)
Reverse osmosis is a well-known Water Purification Technology that uses semi-permeable or partially permeable membranes to selectively separate unwanted molecules, large particles and ions from drinking water. This method uses pressure to overcome the inherent osmotic pressure of the process fluid.
In industry, the reverse osmosis process has become very popular due to its effectiveness in removing impurities and producing high quality water. The importance of this technology extends to the production of drinking water that can retain most of the suspended chemicals and solutes present in the water source.
To illustrate, imagine an industrial environment where reverse osmosis is used to treat water in manufacturing processes. In these situations, the semi-permeable membrane acts as a barrier and prevents the passage of contaminants such as minerals, bacteria, and other unwanted substances. The applied pressure acts as a driving force, effectively pushing water through the membrane and leaving contaminants aside.
When it comes to drinking water production, municipalities often use reverse osmosis systems to ensure that the water supplied to homes meets strict quality standards. Through this process, contaminants are separated, and the resulting liquid on the other side of the membrane is pure and safe to consume.
Fundamentally, the advantage of reverse osmosis lies in its ability to selectively separate components based on their size and molecular properties, making it a versatile and widely used method for water purification in both industrial and domestic applications. Residual solutes remain on one side of the membrane and pure liquid remains on the other side. This demonstrates the simple yet powerful results of this purification process.
The particle down to 0.0001 micron can easily pass through the semipermeable membrane. This membrane also retain Bacteria due to its cells range about 1 to 10 microns in length and from 0.2 to 1 micron in width but water can pass freely which molecular size is 0.000282 micron.
Why Called Reverse Osmosis?
In osmosis, the intrinsic tendency of solutes to flow spontaneously from an area of low solute concentration to an area of high solute concentration is facilitated by a semipermeable membrane. The area with low solute concentration is called the high water potential area, and the area with high solute concentration is called the low water potential area.
To investigate this process in more detail, let us consider a real example using cell membranes. Imagine a plant cell in solution. When the solute concentration in the external environment is lower than the concentration inside the cell, water naturally enters the cell by osmosis. This flow of water helps maintain turgor pressure and keep the cells rigid. In this situation, the extracellular solution is associated with a high water potential, whereas the cell interior is associated with a low water potential.
Now let’s look at reverse osmosis (RO), a practical application of this principle. In situations where water needs to be purified for human consumption or industrial processes, reverse osmosis is used. Here, excessive pressure is applied to force water molecules to pass through a semi-permeable membrane with a high solute concentration (a source of impure water). This process effectively reverses the natural flow of solvent, allowing only pure water molecules to pass through and retaining dissolved contaminants. Reverse osmosis is often used in desalination plants, where seawater is separated from salt and other contaminants and converted into fresh water.
Osmosis is a fundamental biological and physical process, and its practical application in reverse osmosis has important implications for water purification and various industrial processes. Understanding the dynamics of water potential and solute transport can provide valuable insights into these natural and engineered systems.
Use of Reverse Osmosis
Mainly water treatment or conditioning purpose in chemical, pharmaceutical, mechanical industries use Reverse Osmosis System. This process is largely used in water treatment industry as water purification process.
Difference between Osmosis and Reverse Osmosis
| Osmosis | Reverse Osmosis |
|---|---|
| This is the natural process where the solute molecules are passed through a partial membrane from area of lower concentration to higher concentration. | This is the artificial process where the solute molecules are passed through a partial membrane from area of higher concentration to lower concentration upon applied mechanical pressure. |
| Osmosis is a natural process. | Reverse Osmosis is an artificial process. |
| It Occurs along the potential gradient. | It Occurs against the potential gradient. |
| This is observed during welling of resins and other seeds when they are soaked in water. | This is observed during welling of resins and other seeds when they are soaked in water. Widely is used in water purification systems. |
Advantage of Reverse Osmosis
- Reverse osmosis system require less energy consumption due to this system doesn’t allow phase change/separation.
- This system is very much space saving as its very compacted compare to most of the water purification system.
- This a simple standard equipped process so any new comer labor can easily read it.
- The modern reverse osmosis system is totally automated and this is readily shutdown upon interlock system so labor cost is very much low.
- Most of the modern RO system able scheduled maintenance without shutdown of the full plant.
- If anyone want to expand the RO plant; this readily possible without changing the whole RO plant.
- This the most effective form of water purification process and going to popular in day by day.
- Best option for naval ship to make desalination of water to give fresh water to the crew.
- Printing industry use RO system to increase the water quality for different printing purpose.
Disadvantages of Reverse Osmosis
- RO system can’t be use in high concentration solutions.
- This is very much sophisticated which is susceptible to fouling so this system can’t be use without pretreatment.
- Membrane and material of construction must be compatible with the RO feed streams otherwise membrane must be consider.
- The great problem of RO system is that it removes most of the minerals from the feed water and deliver the acidic water. Another big problem is about 20 gallon water must be waste to make 1 Gallon RO treated water.
- RO system is very time much time consuming, it requires near about three hour to make one gallon of water. This means you have to wait all day long to have sufficient water availability at home. This system is not only time consuming but also costly.
How does Reverse Osmosis work?
The operation of a conventional reverse osmosis (RO) system is elegant and simple. Basically, a typical RO system consists of a pump and a semi-permeable membrane. The purpose of the pump is to draw feedwater through a semipermeable membrane and create a flow that promotes the separation of the solutes. The pressure generated by the pump varies from low to high depending on the solute concentration of the feed water. If the feed water contains a large amount of solute, a correspondingly high pressure is required to force it through the semipermeable membrane.
As soon as the feed water is exposed to this pressure and passes through the semi-permeable RO membrane, it is transformed and becomes the so-called permeate water. Conversely, water that leaves the system without passing through the membrane is called wastewater flow.
In standard operation of a semipermeable RO membrane, impressive solute retention rates are achieved, of which more than 95% is sent to the waste stream. These high levels of solutes are an important aspect of the RO process. Although it retains most of the solutes, the semi-permeable membrane allows water molecules to pass through effectively, ensuring that the incoming water is separated from the pure, concentrated solution.
To illustrate, imagine a scenario where the water supply contains significant concentrations of contaminants. In these cases, the pump in the RO system applies significant pressure to force water through the semipermeable membrane. The membrane selectively blocks dissolved substances and allows only pure water to pass through. This efficient separation process ensures the production of clean, pure water, making reverse osmosis a widely used technology in a variety of industries, including water treatment and desalination processes.
Which material didn’t remove by Reverse osmosis?
During reverse Osmosis process a wide range of contaminants such as Asbestos, Salts, Lead, Mercury, Calcium and Iron reduce in significant amount so that a fresh water can produce but it can’t remove the following items-
- Some Pesticide
- Solvents
- Volatile Organic Chemicals
- Metals and Ions such as Radon and Chlorine
- Organic Chemicals such as 2,4-D and 1,2,4-trichlorobenzene, Atrazine, Benzene, Carbon tetrachloride, Dichlorobenzene, Trihalomethanes (THMs) and Toluene
Is it safe to consume reverse osmosis water on a daily basis?
Of course, regular consumption of reverse osmosis water (RO water) is generally considered safe. Reverse osmosis, a water purification method, uses a semi-permeable membrane to remove impurities and contaminants from water. By pressurizing water and forcing it through this membrane, substances such as minerals, bacteria, and certain chemicals are effectively filtered out, creating pure water.
RO water has proven to be a reliable choice for everyday use, especially for those seeking to remove a wide range of contaminants from their drinking water. Despite its purifying properties, reverse osmosis water may still contain some essential minerals that are beneficial to your overall health. To address this issue, some people choose to supplement their mineral intake by adding dietary supplements or mineral supplements to ensure they are getting the nutrients they need.
For example, people who rely heavily on reverse osmosis water can compensate for potential mineral deficiencies by including a variety of nutrient-dense foods, such as vegetables, nuts, and seeds, in their diet. Some people may also choose mineral-fortified water or supplements and take a proactive approach to maintaining a balanced mineral intake.
It is important to remember that individual health care needs may vary. If you have a specific health problem or condition, it is recommended that you consult your doctor or nutritionist. A professional consultation can make recommendations based on your individual needs and help you choose the appropriate water source and diet to meet your specific health goals.
Does reverse osmosis water surpass the quality of bottled water?
Reverse Osmosis treated water remove more than 95% of impurities of feed water and their cost is actually a fraction to bottled water within a years’ time period. So taking a bottled water you have confirm about minerals content of its existing label.
Reverse osmosis (RO) water and bottled water can both be of high quality, but the comparison depends on various factors, including the source of the bottled water and the specific RO system in question. Let’s break down some key points:
Source of Bottled Water:
If the bottled water comes from a natural, clean source, it may already be of high quality without the need for additional purification. However, some bottled water is sourced from municipal supplies, and the purification methods can vary.
Reverse Osmosis Water:
RO is an effective water purification process that uses a semi-permeable membrane to remove contaminants and impurities. RO systems can eliminate a wide range of impurities, including minerals, chemicals, and microorganisms. The quality of RO water depends on the efficiency of the RO system and the maintenance of the filters.
Taste and Mineral Content
Some people prefer the taste of water with certain minerals, which may be present in varying amounts in different bottled waters. RO water tends to be demineralized, as the process removes minerals along with other impurities. Some people find this taste flat and may choose to remineralize the water.
Convenience and Environmental Impact
Bottled water is convenient but can generate plastic waste, contributing to environmental concerns. RO systems provide a more sustainable and cost-effective solution in the long run, as they require less single-use plastic.
Regulations and Standards
Both bottled water and RO systems are subject to regulatory standards, but the stringency can vary by region. It’s essential to ensure that the RO system is properly maintained and meets relevant water quality standards.
In summary, the quality of RO water can surpass that of some bottled waters, especially if the latter is sourced from questionable supplies. However, the comparison is nuanced and depends on individual preferences, the source of bottled water, and the effectiveness of the RO system. Ultimately, both options can provide high-quality drinking water, but factors like taste, convenience, and environmental impact may influence the choice between them.
WHO Guidelines for drinking water
| Serial No. | Materials Name | Content Name |
|---|---|---|
| 1 | Iron | 0.3 mg/L |
| 2 | Zinc | 3.0 mg/L |
| 3 | Copper | 2.0 mg/L |
| 4 | Iodine | Nil |
| 5 | Calcium | Nil |
| 6 | Phosphorus | Nil |
| 7 | Magnesium | Nil |
| 8 | Fluoride | 1.5 mg/L |
| 9 | Sodium | 200 mg/L |
| 10 | Potassium | Nil |
| 11 | Chloride | 250 mg/L |
Which is healthier: Distilled or Reverse Osmosis water?
Both systems are used for water purification and each is tailored to specific requirements. Distillation processes are widely used in industries such as the pharmaceutical industry where the need for high purity water that meets stringent specifications is paramount. In this method, water is exposed to high temperatures and changes into a vapor phase. The steam is then cooled to obtain pure water. This process is very efficient and removes all dissolved substances, including minerals such as calcium and magnesium.
In contrast, reverse osmosis (RO) is a water purification technology that creates pure water by removing various impurities using a semi-permeable membrane. Additionally, minerals are added to improve water quality and preserve its original taste.
For those looking for ultra-pure water, distilled water is the perfect choice. However, to prevent mineral deficiencies, it is important to supplement your diet with mineral-rich foods.
When you choose reverse osmosis water, you get pure water with added mineral content. This makes RO water an ideal choice over distilled water, which can remove important minerals and remove up to 99.99% of the solutes in tap water. Choosing reverse osmosis water not only meets your hydration needs, it also alleviates concerns related to mineral deficiencies, making it a preferred choice for your overall health.
Is reverse osmosis water healthy?
There is no documented evidence that Reverse Osmosis water is harmful to public health issue. If a normal health person take balanced diet regularly then he or she will not suffer any type of gastrointestinal problem. So drinking of RO water is not harmful to your health though RO system remove some minerals during its mechanical process.
Is Reverse Osmosis kill Bacteria?
There are currently thousands of reverse osmosis (RO) systems on the market worldwide, and consumers are happy to use this technology to protect their families from harmful chemicals and pollutants such as lead, arsenic, pesticides, chlorine, and more. Various total dissolved solids (TDS). These consumers firmly believe that their newly purchased reverse osmosis system has the ability to remove all bacteria present in their drinking water. But a disappointing reality is emerging. Contrary to popular belief, reverse osmosis systems are not designed to remove bacteria. Instead, the reservoirs in these systems unintentionally serve as breeding grounds for bacterial growth.
Recent medical studies have revealed the alarming effects of exposure to bacteria-contaminated RO tanks in immunocompromised individuals, including infants, children with autism, and elderly patients. This health condition is scientifically known as heterotrophic plate counting (HPC), a method of measuring colony forming bacteria (heterotrophic bacteria) in drinking water. Removing these bacteria from drinking water has proven to be an almost insurmountable challenge.
Taking these difficult situations into account, practical solutions emerge. Many people choose to incorporate ultraviolet (UV) light immediately after their RO system to neutralize bacteria. It is important to note that UV light does not kill bacteria, but rather disinfects them, preventing them from growing further. This innovative approach is especially essential considering vulnerable populations at risk of health problems due to exposure to bacteria.
However, there are important caveats when considering placing UV lights behind an RO system, especially behind the kitchen sink. This method may not be optimal because UV rays have the unintended consequence of heating the water. As a result, the RO water delivered from the tap becomes hot, affecting the user experience and potentially reducing the efficiency of the overall water treatment process.
To address these complexities, users must recognize the limitations of RO systems and make good use of complementary technologies, such as UV light, to improve water safety. As we explore water treatment technologies, a concise, informed approach is essential to ensure the health and well-being of individuals and families around the world.
How RO System kill Bacteria?
Current trends indicate that modern RO systems typically only have a carbon filter directly in front of the water discharge tank. This setup effectively removes many tastes and odors, but inadvertently creates an ideal environment for many types of bacteria to grow. Recently, “Disinfectant Cartridges” have introduced an innovative system that actively removes electrons from all microorganisms. These innovative cartridges can be used with carbon filters, providing a complete solution to remove 99.99% to 99.999% of bacteria from water.
Reverse osmosis (RO) systems are generally effective at removing bacteria because they pass water through a semi-permeable membrane that blocks particles containing bacteria. However, it is very important to properly maintain your RO system to ensure continued performance and prevent bacterial growth. Here are some steps to eliminate bacteria and maintain a clean RO system:
Regular maintenance
Follow the manufacturer’s recommendations for regular maintenance. This often involves replacing filters and membranes at specified intervals.
Check and replace pre- and post-filters according to manufacturer recommendations.
Sterilization
Disinfect your RO system regularly to remove bacteria and prevent biofilm formation.
Use an appropriate disinfectant solution recommended by the RO system manufacturer. Commonly used solutions include hydrogen peroxide or chlorine-based disinfectants.
Follow the manufacturer’s instructions for the sterilization process, including appropriate dilution and contact time.
Flush the system
Flush your RO system regularly to remove accumulated debris and bacteria.
Follow the manufacturer’s instructions for cleaning the system, as the process may vary depending on your RO unit.
Maintain a clean environment
Make sure the area around the RO system is clean and free of contaminants.
Prevent contaminants from entering the system during maintenance or filter replacement.
Water quality monitoring
Check the water quality in your RO system regularly to ensure it meets desired standards.
If bacterial contamination is suspected, conduct a water quality test for each bacteria and take appropriate action based on the results.
Replace existing components
Replace damaged or worn components immediately, as damaged parts can compromise the integrity of the system and provide an opportunity for bacterial growth.
Temperature control
Maintain water temperature within the recommended range for your RO system. Warm temperatures can encourage bacterial growth.
Professional service
If you are unsure about maintenance or suspect bacterial contamination, you should contact a professional service technician or the manufacturer for assistance.
Always follow the manufacturer’s instructions and recommendations for your specific reverse osmosis system, as maintenance procedures may vary depending on the model. Regular and proper maintenance is important to ensure the performance and longevity of your RO system and prevent bacteria.
What are the components of a Reverse Osmosis System?
List of components for Reverse Osmosis System
- Pressure Vessels & Membranes
- Reverse Osmosis Slide
- Cartridge Filter
- High Pressure Pump
- Control Panel
- Reverse Osmosis Maintenance
- Replace Reverse Osmosis Filters on Schedule
Pressure Vessels & Membranes
You can’t think a Reverse Osmosis System without membranes. The membranes that makes the reverse Osmosis System vary based on the type of water you are deal with. A typical municipal grade water is far difference with hospital grade disinfection water. A membranes is the vital part of the RO system which removes the all types of contaminants, pesticides, dirt, and various types of impurities. Call an expert before selecting the membrane based on your demand. A typical RO system contains more than 100 membranes and size of the
Membrane vary from two and half inch to eight inch and more.
Reverse Osmosis Slide
Make your RO System more durable by the help of the carbon steel frame where you can mount all of the component of your Reverse Osmosis systems. This type of frame need to be more supportive as it have to act against vibration of the RO pumps and it is better to mount the RO system to the ground base for better performance.
Cartridge Filter
Most of the recent RO system comes up with cartridge filter to prevent particle to hit directly to the membrane. Actually cartridge help the membrane filter to damage itself. This cartridge filter made of five micron spun polypropylene and this can be expand if required. It is design in such a way that it can withhold the sufficient filter come from feed water pump.
High Pressure Pump
Most of the commercial and industrial settings use high grade pump so that the rejection rate from the Reverse Osmosis System comes out as vital. This is very much desirable that the quality of the membrane must be match the horse power of the high pressure pump so that a better match develop for the suitable system.
Control Panel
A RO system is always comes up with advance PLCs or solid state microprocessor depending control systems how advance level control systems you demand. The control system can be use the multiple system at time like cleaning, chemical dosing, pretreatment and other component also. You can use another component with this system if you want.
Reverse Osmosis Maintenance
A Reverse Osmosis system last more than 10 years if it properly maintained. If you want to last your Reverse Osmosis system then you have to maintain your system regularly. Here is the best way to maintained your favorite RO system
Replace Reverse Osmosis Filters on Schedule
Generally you will find the information at the RO system manual, please read carefully the instructions where your RO system contains three to five stages filter and each filter has replacement due date. A modern RO membrane need to change every two years. RO system replacement kid always available at the current market.
You may not replace the RO membrane so before buy check filter with RO membrane and filter without RO membrane which is your requirement.
Different type of RO Filter and their longevity
List of RO Filters
- Sediment Filter
- Carbon Filter
- Reverse Osmosis Membrane
- Polishing (GAC) Filter
Sediment Filter
Actually the sediment filter is designed to protect membrane filter and this filter remove all type of sediment, strain, dirt and silt and this filter need to remove every 12 month. This filter protect the membrane filter from various type of dissolved solute so that the membrane filter longevity increase. As the membrane is most costly than sediment filter so to protect the membrane filter you have to change the sediment filter in every 12 months to run the system without any significant harm.
Carbon Filter
There are two types of carbon filter include in modern RO system which are carbon block filter and granular activated carbon (GAC) filter. This type of carbon filter actually designed to filter the various types of contaminants, lead, pesticides and chlorine. Both of the carbon filter possess high adsorption power. The filters to be replace within 6-12 months. The longevity of carbon filter depends on how much dirty water you are deal with. If you are deal with high dirty water your filter will be block within short period of time.
Reverse Osmosis Membrane
The RO semipermeable membrane design to allow water but it will filter out all types of contaminant. If timely replace the carbon filter and sediment filter in every years or timely manner then your membrane filter longevity will increase almost two years.
Polishing (GAC) Filter
A modern RO system the final filter polish the water to perform the final stage cleaning of the water remove remaining odor and taste. The Granular Activated Filter (GAC) ensure that you are deal with the outstanding drinking water.
If fail to replace the filter in time then then this system damage the whole system and your water flow may decrease gradually in to the faucet. When you observe the water flow is decreasing then this the best time to change the filter.
All the filter in RO system to be change within 6-12 months except RO membrane filter and this membrane filter to be change within 2 years.
RO System Maintenance Checklist
A reverse osmosis system to be sanitize and recharge annually. Call a local expert to perform the job accordingly otherwise you have to confirm that are able to do the same.
If you think you can do it, then you have to read the RO system manual clearly about sanitization of the RO system then do the same
How to Clean and Sanitize Your System Annually
- Check all the packages of the filters are new and ready for use.
- All the area is clean and fit service of the RO system
- Remove all the excess dirt and dust.
- Firstly wash your hand soap the wear a sanitary gloves
- Shut down the main valve
- Clear all water from RO faucet
- Remove Carbon Filter and sediment filter from its housing
- Then remove the RO membrane from its housing
- In stage one housing pour one cup of Hydrogen Peroxide
- Attain attach the all connections
- Turn the main valve
- Run the system and this will fill rapidly as no filter attached here
- In this condition run at least to cycle
- Shutdown the main valve again
- Now install the main brand new filter
- Fill the tank and drain out more than two times
- Now your system is ready to use and repeat this process in every one year
Can Reverse Osmosis System handle Hard Water?
If you have very hard water, consider using a whole house water softener before using a reverse osmosis system. Magnesium and calcium cause water hardness and these elements can cause RO systems to become clogged. First, a water softener is installed to treat the water before it reaches the RO system.
In areas where water hardness is a concern, it is essential to comprehensively address this issue by installing a whole home water softener. The main causes of water hardness are magnesium and calcium ions. When these ions are present in high concentrations, they can be problematic for existing water treatment systems such as reverse osmosis (RO). The inherent limitations of RO systems in effectively processing minerals that produce this hardness can lead to clogging problems and reduce the overall efficiency and lifespan of the RO system.
To illustrate, let us consider a real situation where a household in an area with high water hardness does not pre-treat with a water softener and relies solely on an RO system. Magnesium and calcium ions in untreated water tend to accumulate on the RO membrane, gradually forming scale deposits. Over time, these deposits interfere with the filtration process, reducing water flow, increasing energy consumption, and increasing RO system maintenance.
One strategic approach to alleviate these problems and ensure optimal performance is to install a water softener upstream of the RO system in the water treatment sequence. Water softeners effectively reduce the concentration of magnesium and calcium ions, preventing them from building up in the reverse osmosis system. By implementing this two-step treatment process, the water is first softened to eliminate hardness issues and then sent to the RO system for further purification.
In summary, integrating a whole house water softener in front of a reverse osmosis system has proven to be a practical and efficient solution in areas with higher water hardness. This method not only ensures RO system performance, but also improves overall water quality by addressing specific mineral content issues early in the treatment process.