How to control microbial contamination in reverse osmosis membrane systems
The weather is very hot, and we need to start paying attention to microorganisms that thrive in high temperatures to prevent them from contaminating reverse osmosis membrane elements and affecting the normal operation of the water treatment system.
Bacteria, algae, fungi and their spores, and viruses, etc. The content of microorganisms in water is very large. Under suitable conditions, they can metabolize in large quantities on the surface of the reverse osmosis membrane, forming a biofilm. Among various types of membrane element contamination in reverse osmosis equipment, microbial contamination is the most serious and has the following characteristics:
1. Microorganisms grow rapidly. Once bacterial colonies appear on the membrane surface, a slime layer will quickly form, causing an increase in system inlet pressure, an increase in pressure difference, and a decrease in water production. Generally, the first membrane is more severely polluted, and membrane surface and flow channel pollution will occur simultaneously.
2. Microbial contamination is difficult to clean. Biological slime films are insoluble in acid and difficult to dissolve in alkali. Even frequent flushing cannot remove them.
Currently, the main method to prevent microbial contamination of reverse osmosis membranes is to reduce biodegradable organic matter and sterilization in the pretreatment stage. Conventional sterilization methods include adding chlorine or hypochlorite, ozone, ultraviolet light, etc. Non-oxidative bactericides such as DBNPA or isothiazolinone can also be used for shock sterilization of the reverse osmosis system.
When microbial contamination occurs in the reverse osmosis system, sterilization and chemical cleaning should be carried out in time to prevent the massive reproduction of microorganisms. To prevent microorganisms from developing drug resistance, the type and method of sterilization should be changed regularly.
