Regular chemical cleaning of RO membranes will ensure that they continue to perform and extend their useful life. The key thing with cleaning is to do it before the situation gets too bad because if you leave it too long the membrane may become irretrievably fouled. Cleaning should be undertaken whenever the normalized permeate flux reduces by 10 – 15% or, either the normalized differential pressure or permeate conductivity increase by 10-15%. In many instances, it is best to adopt a programme of regular preventive cleaning.
Depending on the characteristics of the water supply membrane fouling may be inorganic, organic, colloidal or microbiological in nature and often a combination. Each type of fouling requires a different cleaning strategy.