Heavy contamination of reverse osmosis membrane elements

What is heavy contamination of reverse osmosis membrane elements？

Heavy contamination of reverse osmosis membranes means that the pressure difference in a single section after contamination is more than twice the value of the pressure difference in a single section at the beginning of the system's operation, that the water production of the reverse osmosis system drops by more than 30% or that the weight of a single reverse osmosis membrane element exceeds the normal value by more than 3 kg.

Heavy contamination is often a combination of heavy physical and heavy chemical contamination, and in some cases, both at the same time.

Reasons for heavy contamination of reverse osmosis membrane elements

Due to the different water quality of water sources around the world, the adopted and treatment methods are not the same, so the causes of RO membrane elements are not the same, the common causes and characteristics of pollution are as follows.

Water treatment process system design and manufacturing defects

① For the reverse osmosis pretreatment filter, the source water is not well water, the equipment filtration rate is greater than 8.5 m / h, while the surface water design in the equipment filtration rate is greater than 8 m / h, resulting in reverse osmosis feed water SDI exceeds the standard.

② The source water contains impurities such as colloids and suspended matter, which are not removed in the design.

③ COD>3 in the source water without removal measures.

④ Reverse osmosis membrane element design flux exceeds the standard of the reverse osmosis device second section fouling and differential pressure rise fast, water production decay and desalination rate decline fast.

Improper selection of reverse osmosis additives and other consumables

① Inappropriate choice of reverse osmosis scale inhibitor type or dosage

② Improper selection of flocculants and coagulants in the RO pretreatment system can cause serious contamination of membrane elements

③ Improper selection of bactericides can cause serious damage to the desalination rate of the reverse osmosis system.