In the entire process of applying ro membrane element, after a period of regular use, the surface of the membrane will be polluted by the environment and needs to be cleaned for faster application.
1. Purpose of cleaning ro membrane element
After ro membrane element is used for a period of time, the surface of the membrane will be polluted by the environment, such as surface fouling and blockage of the membrane surface. At the same time, the compaction of the membrane will reduce the permeability coefficient of the membrane. The environmental pollution blockage of the membrane is mainly caused by accumulation on the membrane surface and biological reproduction. Among them, the microbial strains not only block the membrane, but also corrode and destroy the cellulose acetate membrane. The permanganate index will cause the membrane function to decline. If the environmental pollution on the membrane surface cannot be eliminated immediately, it will cause irreparable damage to ro system membrane, which will directly affect all the normal water production rate and water body of ro system membrane. The cleaning is to better repair the original ro membrane element. There are characteristics.
2. Physical cleaning method ofro membrane element
Among them, physics uses the pressure of mechanical equipment to eliminate contaminants on the membrane surface. No other chemical changes can occur during the entire cleaning process. The physical method can be divided into five methods: manual cleaning, adiabatic process hydraulic washing, reverse washing, boiling water washing, and water-air mixed washing.
(1). Manual cleaning method.
This is a relatively initial but efficient method. The method is to use a soft chemical substance (such as sponge) to gently scrub the stains on the membrane, and rinse off the removed membrane for ro water purifier with tap water. This method can reasonably remove many stains on the surface. But it can't do anything about the finer debris in the deep membrane pores.
(2). Isobaric hydraulic flushing method.
This method can be used to clean membrane for ro water purifier in all configurations. The specific method is to close the water production gate valve and open the concentrated water inlet and outlet gate valves to flush the membrane surface at an expanded flow rate and reasonably remove many soft residues on the membrane surface. The effect of washing in the heat preservation process is also related to the number of continuous washings.
(3). Backwash method.
The reverse direction flushing method is a method of flushing from the reverse side to the front side of ro membrane element, which is also a practical cleaning method. After washing in the opposite direction, water washing is carried out during the heat preservation process, and the actual washing effect is very significant.
(4). Boiled water washing method.
Rinse the surface of the membrane with heated water (30~40~C) to remove these viscous and soluble residues (such as glycogen).
(5). Water and air mixing cleaning method.
The purified compressed gas and water are sent to the ultrafiltration device together, and the water-gas mixed liquid will produce a strong stirring effect on the membrane surface to remove residues that are difficult to remove. The actual effect is also better.