Reasons for Shortened Lifespan of Reverse Osmosis Membranes in Pure Water Equipment

Reverse osmosis membranes are a core component of pure water equipment. Improper use can damage the membrane and shorten its lifespan. So, what are the determining factors for the lifespan of a reverse osmosis membrane in pure water equipment?

I. Incorrect Shutdown Procedures for Reverse Osmosis Equipment

A. Rapid pressure reduction without thorough flushing during shutdown. Because the concentration of inorganic salts on the concentrate side of the membrane is higher than in the feed water, scaling and membrane fouling are easily formed.

B. Flushing with pretreated water containing chemical reagents. Water containing chemical reagents can cause membrane fouling during equipment shutdown.

II. Inadequate Residual Chlorine Monitoring in Reverse Osmosis Equipment

1. Residual chlorine can damage the membrane if the dosing pump malfunctions, the dosing solution is ineffective, or the activated carbon is saturated.

2. Damage to membrane performance caused by untimely or incorrect cleaning methods.

III. Damage to the Membrane Due to Improper Operation of Reverse Osmosis Equipment

Residual gas operating under high pressure in reverse osmosis equipment can form air hammer, which can damage the reverse osmosis membrane.

Two common scenarios occur:

A) After purging the equipment, if the gas is not completely expelled before rapid pressurization, the remaining air should be expelled at a pressure of 2-4 bar before gradually increasing the pressure.

B) If the joint between the pretreatment equipment and the high-pressure pump is poorly sealed or leaks (especially with the microfilter and its downstream piping), and the pretreatment water supply is insufficient, air may be drawn in due to vacuum at the poorly sealed areas if the microfilter becomes clogged.

IV. Inadequate maintenance of reverse osmosis equipment leading to microbial contamination

This is a common problem in the use of composite polyamide membranes. Because polyamide membranes have poor resistance to residual chlorine, improper dosing of chlorine and other disinfectants, coupled with insufficient user attention to microbial prevention, easily leads to microbial contamination.