What are the requirements of reverse osmosis equipment for inlet water quality?

Edit:        Date:2019/3/6 17:25:04        Click:543

    With the development of water treatment industry, the range of pure water purification equipment is becoming wider and wider, which can be used in chemical industry, medicine, food and other industries.There will be a full set of pretreatment devices in the whole system, mainly for the preliminary treatment of raw water, to achieve the reverse osmosis host water requirements.


一、Reverse osmosis system parameters

1, temperature (℃) : 1-45.

2. PH value: 2-11.

3. Silt density index (SDI)<4.0.

4. Turbidity (NTU)<1.0.

5. Organic content (COD, mg/L)<1.5.

6. Residual chlorine content (mg/L)<0.1(actually controlled at 0).

7. Iron content (mg/L) : when dissolved oxygen > was 5mg/L, Fe<0.05.

8. SiO2(mg/L) : SiO2<100 in concentrated water.

9. LSI: pHb-pHs<0.

10. Sr, Ba, etc. are easy to form insoluble salt ions: Ipb< 0.8ksp.

The last three items can be appropriately increased by adding scale inhibitor.


二、Reverse osmosis inlet water requirement what harm will be caused to the reverse osmosis system if it is not up to the standard?

1. If one or more of the above indicators fail to reach the standard, the reverse osmosis membrane will be affected as follows

(1) RO reverse osmosis film scale formation.

(2) RO reverse osmosis membrane is polluted by metal oxides.

(3) The suspended matter fouls the RO reverse osmosis membrane.

(4) colloid pollution.

(5) COD in effluent increased due to organic and microbial pollution.

2. It will further affect the whole reverse osmosis purified water system as follows:

(1) reduce the yield of reverse osmosis pure water purification system.

(2) water production quality of low angdi reverse osmosis water purification system.

(3) increase the energy consumption of reverse osmosis equipment operation, including raw water and electricity consumption.

(4) increase the operating cost of water treatment, including reverse osmosis scale inhibitor, resin regeneration salt, and other water treatment agents.

When the pretreatment is not done well, the reverse osmosis inlet water quality is seriously substandard, and the time is too long, it will lead to irreversible physical and chemical damage of the reverse osmosis membrane element, greatly shorten the service life of the reverse osmosis membrane element.

三、 Role of reverse osmosis pretreatment

Pretreatment of reverse osmosis unit plays an important role in ensuring the safety, reliability and economy of reverse osmosis unit.The purpose of reverse osmosis pretreatment is to solve the following problems to ensure the stable operation and service life of reverse osmosis device.

(1) prevent film surface scaling (including CaCO3, CaSO4, SrSO4, CaF2, SiO2, iron and aluminum oxide, etc.).

(2) prevent colloid substances and suspended solid particles from fouling.

(3) prevent fouling of organic matter.

(4) prevent microbial fouling.