What is the reason for the discharge of wastewater from the reverse osmosis water purifier?

Reverse osmosis technology is a new membrane separation technology that relies on reverse osmosis membranes to separate solvents and solutes in a solution under pressure. The selective permeability of reverse osmosis membrane to solution and the effect of external driving force are used to overcome Osmotic pressure, so that the solvent can be separated through the osmosis membrane. But why does reverse osmosis equipment have wastewater?

The principle of reverse osmosis membrane

Put the same volume of dilute solution and concentrated solution on both sides of a container respectively, and block the middle with a Semipermeable membrane. The solvent in the dilute solution will naturally penetrate the Semipermeable membrane and flow to the concentrated solution side. The liquid level on the concentrated solution side will be higher than the liquid level of the solution to form a pressure difference and reach the osmotic equilibrium state. This pressure difference is the Osmotic pressure. The Osmotic pressure depends on the type of concentrated solution, The concentration and temperature are independent of the properties of Semipermeable membrane.

If a pressure greater than Osmotic pressure is applied to the concentrated solution side, the solvent in the concentrated solution will flow to the dilute solution. The flow direction of this solvent is opposite to the original direction of penetration. This process is called reverse osmosis.

We can flow water from high concentration solutions to low concentration solutions through the reverse osmosis process. Due to the inability of inorganic ions, colloidal substances, and macromolecular solutions to pass through the reverse osmosis membrane, in our process, substances that we do not need are left at the high concentration end of the solution, while the low concentration end is the purified liquid we obtain

Technology adopted by reverse osmosis pure water machine

1. Overview of Traditional Water Purification Technologies

Traditional drinking water treatment mainly uses flocculation, sedimentation, sand filtration, and chlorine disinfection to remove suspended solids and bacteria in the water, while the removal effect of various dissolved chemicals is very low. With the intensification of environmental pollution from water sources and the improvement of drinking water standards in various countries, the "deep treatment" of drinking water that can remove various organic and harmful chemicals is increasingly receiving attention.

2. Deep water purification technology

The current advanced treatment methods mainly include activated carbon adsorption, ozone treatment, and membrane separation. Microfiltration and ultrafiltration in membrane separation cannot remove various low molecular substances, so they cannot be referred to as deep treatment when used alone.

The pure water machine adopts the advanced reverse osmosis technology in the current water purification industry. Reverse osmosis membranes can intercept various inorganic ions, colloidal substances, and macromolecular solutes in water, thereby obtaining purified water. It can also be used for pre concentration of macromolecular organic matter solutions. Due to the simple process and low energy consumption of reverse osmosis, it has developed rapidly in the past 20 years. It has been widely applied in seawater and brackish water desalination, boiler water softening, and wastewater treatment, and combined with ion exchange to produce high-purity water. Its application scope is currently expanding, and it has begun to be used for the concentration of dairy products, fruit juices, as well as the separation and concentration of biochemical and biological agents.

Reasons for Wastewater Discharge from Reverse Osmosis Pure Water Machine

The working process of reverse osmosis membrane, the core component of the water purifier, is actually a process of liquid concentration. As the water flows through the reverse osmosis membrane surface, the salt content in the water increases continuously, and the Osmotic pressure of the water also increases continuously. When the Osmotic pressure increases to the pressure of the Booster pump, the water cannot flow into the purified water end through the reverse osmosis membrane. Due to the continuous increase in mineral concentration in water, some minerals will accumulate on the surface of the reverse osmosis membrane and block the pores of the membrane, leading to a decrease in water production and desalination rate of the reverse osmosis membrane. During the operation of a pure water machine, the above phenomena should be avoided, so all reverse osmosis membranes in use will have a ratio that can convert the influent water into product water, called the "recovery rate"

Recovery rate=product water volume ÷ water inflow × 100%

If a reverse osmosis system has a high yield of water, it means that the reverse osmosis membrane system has a higher recovery rate. Usually, we can improve the recovery rate of the system by adding the reverse osmosis in series, but the household water purifier usually uses only one reverse osmosis membrane, which also means that the reasonable system recovery rate of almost all the Almost all sold on the market is the same. Any product higher than this reasonable value is a product with unreasonable design, which is at the cost of reducing the service life of the reverse osmosis membrane. The current reasonable and economical recovery rate is 30%.

The above is what Hongjie Water brings to you about "What is the reason for the discharge of wastewater from reverse osmosis water purifiers?" We hope it can help you!

Shenzhen Hongjie Water Technology Co., Ltd. is an integrated high-tech enterprise specializing in product development, production, sales, engineering design, installation and commissioning, technical consultation, and sales of supporting materials in the field of industrial water treatment and drinking water treatment. Main products: design, manufacturing, installation, commissioning and maintenance of water treatment equipment such as pure water equipment, Ultrapure water equipment, reverse osmosis equipment, GMP purified water equipment, EDI deionized water equipment, domestic sewage equipment, industrial wastewater equipment, softened water equipment and reclaimed water reuse equipment.