A set of reverse osmosis equipment contains a lot of technical processes and different product accessories. MBR membrane is the most common component of reverse osmosis equipment. However, after a long period of use, the effect of the membrane will be reduced. There are two kinds of cleaning methods for the membrane, one is physical method, the other is chemical method.

Physical methods include hydraulic flushing, ice-vapor mixed flushing, countercurrent flushing and sponge ball flushing. Hydraulic flushing mainly uses hydraulic flushing with high flow rate after decompression to remove membrane contaminants. Water-vapor mixed washing eliminates polarization layer by shearing between vapor and film surface. The pressure is about 0.3 MPa. The film surface is washed with fresh water or air-fresh water mixed liquid. The cleaning time is generally 30 minutes.Countercurrent cleaning is the application of reverse pressure on the support layer in hollow fiber components, which causes the reverse flow of the membrane through the liquid to loosen and remove the pollutants on the surface of the activated layer on the feed side of the membrane. Sponge ball cleaning relies on hydraulic impact to make the diameter of the sponge ball slightly larger than the diameter of the tube flow through the membrane surface to remove pollutants on the membrane surface. However, this method is limited to the use of internal pressure tubular membrane assemblies.

Chemical method is to use a certain chemical cleaning agent to wash or circulate the film surface under certain conditions. In chemical cleaning, we must pay attention to the following two points:

1. The detergent must have a good ability to dissolve and decompose pollutants.

2. The cleaning agent must not pollute or damage the membrane surface.

Warm Tip: For cleaning process of different pollutants, the range of pH value allowed by membrane, working temperature and chemical stability of membrane to cleaning agent itself should be considered. Commonly used cleaning agents include nitric acid, phosphoric acid, citric acid, sodium hydroxide and so on.