Principle of Reverse Osmosis System

1. The Fundamental Concept of Reverse Osmosis Equipment

RO reverse osmosis technology is a high-tech water treatment method that uses the properties of reverse osmosis membrane to separate solvent and solute in a solution under pressure. Physical phenomenon constitutes ” osmosis “.
In reverse osmosis, a higher pressure than natural infiltration is applied to water containing salt and various fine contaminants (i.e., raw water), causing the water to flow from the side with the highest concentration to the side with the lowest concentration. Most fine pollutants, organic debris, heavy metals, bacteria, viruses, and other dangerous things in raw water are expelled through the sewage outflow.

2. Flow Diagram for RO Water Equipment



3. Main Process Flow of RO Pure Water Equipment


1. Raw water is stored in the raw water tank and used to settle big particles of silt and other compounds that can precipitate in water. In addition, it mitigates the impact of the raw water pipe’s unstable water pressure on the water treatment such as the pressure sensor’s response to too low or too high water pressure.

2. Raw water pumps are utilized for pretreatment, maintaining system pressure, and stabilizing the water supply.

3. The quartz consists of numerous filter layers. Its primary function is to remove particles larger than 20 um from raw water, suspended solids, and other compounds. The equipment can be controlled by a manual valve or a fully automatic controller to execute various tasks, including backwashing and positive flushing.

How Do Industrial Sand Filters Work

4. The activated carbon filter solution uses a shell-shaped activated carbon filter. Activated carbon is capable of both adsorption and ion exchange adsorption of electrolyte ions. Adsorption by activated carbon can also reduce the oxygen consumption (COD) of potassium permanganate from 15 mg/L (O2) to 2-7 mg/L (O2). 

In addition, the system functions as a catalyst due to the increased concentration of adsorbed molecules on the surface caused by adsorption. It may eliminate pigments, odors, and many biochemical organic chemicals in water, reduce the residual chlorine value of water and pesticide pollutants, and eliminate trihalides (THM) and other contaminants.

The system offers manual valve control or an automatic controller to perform a series of operations such as backwashing and positive flushing. Guaranteed are the equipment’s water quality and prolonged service life. In addition, the equipment is self-maintaining and has relatively minimal operating expenses.

5. Sodium ion softening system, dosing system, and RO device can discharge the concentration of dissolved solids and make use of freshwater.

Before entering the reverse osmosis membrane module, an ion softening device or an appropriate scale inhibitor should be used to prevent the precipitation of carbonate,  SiO2, and sulfate crystals.

Figure 4 Mixed-bed deionizer.

This can prevent CaCO3, MgCO3, MgSO4, CaSO4, BaSO4,  SrSO4, and SiSO4 from appearing at the concentrated water end, especially on the concentrated water side after the RO unit, where the concentration product is greater than its equilibrium solubility constant and crystallizes, which damages the original characteristics of the membrane.

6. The precision filter includes a high-quality filter to remove the suspended solids, particles, and colloids from the feed water, allowing the RO system to operate. Continuous equipment operation is more reliable and safer. The filter element is a 5um melt-blown filter element designed to prevent the top filter unit from eliminating missed particles greater than 5um. Prevent the reverse osmosis device’s surface from harming the membrane, consequently compromising the membrane’s desalination performance.

7. Reverse osmosis system: The reverse osmosis device uses sufficient pressure to separate the solvent (usually water) in the solution through the reverse osmosis membrane or semi-permeable membrane. This process is referred to as “reverse osmosis” because it occurs in the opposite direction of normal osmosis.

Reverse Osmosis Systems work flow

The reverse osmosis method can adapt to various types of raw water with saline content, especially in water treatment projects with high saline content. It can obtain good technical and economic benefits. The desalination rate of the reverse osmosis method is improved, the recovery rate is high, the operation is stable, the floor area is small, and the process is simple. While desalting, reverse osmosis equipment removes most bacteria, colloids, and large molecular weight organic matter.

8. Ozone sterilizer (optional) kills the bacteria caused by secondary pollution to completely ensure the hygiene index of the finished water.

4. The Main Characteristics of Reverse Osmosis Pure Water Equipment

  • High desalination rate, long service life, and low operating cost. 
  • A fully automatic pretreatment system is adopted to realize unmanned operation. 
  • Adopt the Nanfang booster pump (optional brand), high efficiency, low noise, stability, and reliability.
  • To ensure the safety of water quality, online monitoring and control of water quality and real-time monitoring of water quality variations are required.
  • Fully automatic electric control system with an optional touch-screen interface, user-friendly.
  • Line with local water quality to meet the needs in an all-around way.

Reverse Osmosis System

5. Operating Parameters and Effluent Indicators of Reverse Osmosis Pure Water Equipment

  • Stand-alone output: 0.25M3/H-120 M3/ H (customized according to customer needs)
  • Desalination rate: Reverse osmosis system ≥ 97% (single-stage or double-stage customized according to customer needs)
  • Operating pressure: 1 Mpa-1.5Mpa
  • Recovery rate: 50% – 80%
  • Product effluent conductivity: <10μs/ CM (raw water <500μs/CM)
  • Outlet Water Quality: Depending on your needs for water treatment. Can meet international water quality requirements.

6. Typical Customers and Scope of Application of RO Pure Water Equipment


RO Equipment applications


  • Pure water preparation in production plants: It is equipped with a clear automatic filling machine to form a fully automatic barreled water / bottled water production line.
  • Food industry raw material preparation water: Such as a blending of additives, proportioning of ingredients, soup, or juice, etc., can improve the taste, inhibit the growth of organic matter, and increase the shelf life of products.
  • Water preparation for dairy products, beverages, and wine-making industries: It is recommended to use a two-stage reverse osmosis device to prevent bad taste caused by foreign matter in the water. Maximize the improvement of product quality, inhibit the reproduction of organic matter, and increase the shelf life of products
  • Chemical industry water: It is used for the proportioning of chemical raw material liquids, chemical product manufacturing, chemical circulating water, etc., to effectively prevent additional chemical reactions and quality deviations caused by excessive ions in the water.
  • Boiler water in the power industry: It is used for boiler supply water, supply water for thermal power boilers, and medium and low-pressure boiler power systems in factories and mines. Improves production efficiency and extends the service life of the equipment.
  • Desalination of seawater and brackish water for drinking: It is used for desalination of water sources in islands, ships, offshore drilling platforms, and brackish water areas to make it meet the standard for direct raw drinking.
  • Breeding and horticultural water supply: It is used in the animal husbandry industry to desalinate brackish water, promote animal growth, and prevent various diseases caused by water quality problems. Also used in gardening, cultivation, breeding cultivation, etc., to improve biological activity.
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