Filtration and reverse osmosis (RO) are two different methods of removing impurities from water. The main difference between the two is the particle size they can remove. Filtration is a simpler and less efficient method of removing impurities from water than reverse osmosis, which is a more complex and advanced process that removes a wider range of impurities.

Reverse osmosis filter tap closeup with dripping water-drop.

Filtration is a physical process that involves passing water through a porous material, such as sand or a membrane, to capture and remove particles and impurities. Filtration removes suspended solids, sediment, bacteria, and some chemicals, but not dissolved salts, minerals, or metals.

Reverse osmosis, on the other hand, is a more advanced filtration process that uses pressure to force water through a semi-permeable membrane. This membrane has very small pores and can remove almost all impurities in the water, including dissolved solids, minerals and metals.

What is Reverse Osmosis?

As a water purification method, reverse osmosis mainly uses semi-permeable membranes for separation treatment. This method is very suitable for raw water treatment such as seawater, and can effectively separate large particles, ions, and unwanted molecular substances in the liquid. By applying pressure, the osmotic pressure is overcome to achieve the effect of purification. It can also remove dissolved substances in water, bacteria, and some suspended chemicals.

reverse osmosis is a water purification method

Reverse osmosis can be used in industrial processes and desalination of seawater. In its process, the reverse osmosis membrane is selective, allowing only small particles to travel freely, while large particles or ions are blocked from passing through the membrane pores. That is, the solute will be retained on the pressurized side of the semipermeable membrane, while the pure solvent will pass through the membrane.

What is Filtration?

Filtration is an analytical technique used to separate solid impurities from liquids. The filtration process is to maintain a barrier of solid particles through physical, mechanical, or biological operations so that the solids in the fluid can be removed when the fluid passes through. The fluid can be either a liquid or a gas, the barrier used for filtration is the filter, and the liquid obtained after filtration is the filtrate. Filters include surface filters, depth filters, high-flow filters, etc., all of which can capture solid particles, and are selected according to actual applications.

In general, filtration is not a finishing process leading to purification. Since some solid particles may pass through the filter, some fluid may remain in the filter and not enter the filtrate. Compared to decantation Filtration is more precise. Filtration technology includes thermal filtration, vacuum filtration, ultrafiltration and many other types.


What is the Difference Between Filtration and Reverse Osmosis?

In terms of fluid flow mechanics, reverse osmosis differs from filtration. In reverse osmosis, fluid flows through a semi-permeable membrane, while in filtration a filter medium is used. The main difference between the two is that reverse osmosis uses a semi-permeable membrane for separation, while filtration uses a filter medium for separation.

Filters physically remove dirt and sediment particles from the fluid, down to about 1 micron, but some dissolved chemicals cannot be removed. Reverse osmosis uses semi-permeable membranes to filter molecules and also remove dissolved chemicals and salts that cannot be filtered out by conventional filters.

How Do Industrial Water Filters Work?

Regardless of the industry, the demand for water in industrial processes is only increasing. This involves water filtration systems, reverse osmosis treatments or filter treatments to ensure the proper functioning of industrial processes.

Water filtration is essential because, without it, the water might become nasty or corroded. Water pollution occurs when pollutants fill the water. Industrial equipment also becomes less efficient, so water cannot be treated properly. Contaminated water should not be used anywhere unless it has been purified beforehand.

Pump station for reverse osmosis industrial city water treatment station. Wide angle perspective

Industrial water treatment is not only to remove impurities in the water but also to keep the operating system from being blocked by dirt as much as possible to reduce maintenance costs. Fouling, fouling of boilers, loss of thermal efficiency, and corrosion of pipes all arise from the use of untreated water.

How does Reverse Osmosis work?

The reverse osmosis process works by using a high-pressure pump to increase pressure on the salt side of the RO membrane and force water through the semi-permeable RO membrane, removing up to 95% of the dissolved salt.

The pressure required for operation is directly proportional to the salt concentration of the feed water; the higher the concentration of the feed water, the higher the pressure necessary to overcome osmotic pressure.

The permeate water in a reverse osmosis system is desalinated or deionized desalinated water, whereas the concentrate stream contains concentrated pollutants that have not gone through the RO membrane.

Options for Purifying Industrial Water

The purpose of the industrial filtration system is to remove most of the pollutants and particulate impurities present in the water. There are many different types of industrial filtration systems to choose from. The following is a part:

Pipeline/Basket strainer: This is a closed water filtration system that primarily uses a removable mesh screen or basket to collect contaminants.


Automatic self-cleaning filter: This is a self-cleaning water filtration system that collects debris and waits for a certain amount of pressure to build up in the system to open the flush valve to flush out the remaining contaminants.

Automatic self-cleaning filter

Ultraviolet purification: This water filtration method is the most environmentally friendly, mainly using ultraviolet rays to destroy the DNA of pollutants in the water and make those microorganisms dead.

Bag filter: This is a relatively simple industrial filter that captures particles and solid contaminants that pass through the filter.

bag filter

Reverse osmosis: This type of water filtration system uses reverse osmosis to filter water, mainly using a semi-permeable membrane, which is a heavy-duty water filtration system.

Media Filter: This filter is made up of several layers of different materials that allow the water to pass through and any large contaminants are captured in the process.

How is RO Used in Industrial Processes?

RO is a water purification technology that is utilized in a variety of industrial applications. The following are some specific applications of reverse osmosis systems in industrial processes:

Municipal water purification

Municipal water is primarily for domestic and commercial use. Its need for high-quality water is far more than washing purposes in industry. The food and beverage industry always pursues quality control, and the taste of soda or products is uniform. Due to the problems of microbial contamination, chemical residues and salinity in the water source, the municipal water can use the reverse osmosis system to purify the water source to ensure high-quality water.


The only water source in many densely populated areas is the ocean, and the salt content of the ocean is 35,000 mg/L, which cannot be directly used for production and life. Although seawater industrial applications, offshore transportation and offshore drilling all rely on the ocean, long-term use of high-salt water can cause great damage to ship equipment. In order to remove the salt in seawater, a reverse osmosis system is installed to fully achieve the desalination effect of seawater and reduce chemical and bacterial pollution.


Brackish water desalination

Brackish water generally refers to a mixture of fresh and salt water, which contains 1000 to 15000 mg/L of dissolved salts. For industrial and drinking water applications, the salt content of the water must not exceed 500mg/L. The desalination of brackish water is also inseparable from reverse osmosis technology.

Boiler feed water

Industrial boilers also have high water quality requirements and are extremely sensitive to hard water. Equipment that uses hard water at high temperatures will suffer from fouling, heat transfer defects, and shortened boiler vessel life cycles. Therefore, the boiler system can only use demineralized water. Industries such as pharmaceuticals, pulp, and chemicals utilize reverse osmosis systems for pre-boiling water treatment.

Boiler feed water

Wastewater treatment

Reverse osmosis is a water purification technology used in the water treatment industry that is often employed as a final step to eliminate chemicals, bacteria, and dissolved pollutants. In the wastewater sector, reverse osmosis units are utilized in tertiary water treatment. Before release, industrial wastewater is also processed using a reverse osmosis system.


Filtration is a method of separating a solid from a liquid. Reverse osmosis is a water purification technology that separates water using a partially permeable membrane. The primary distinction between filtration and RO is that filtration uses a filter media for separation, whereas reverse osmosis employs a partly permeable membrane.

If you are having trouble choosing the filtration system or ro system for your industrial process, please feel free to contact us and our technical engineer will help you!

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