The sanitization of RO/NF membrane systems as described in this chapter is the application of biocidally effective solutions or hot water to the membranes while the system is offline, i.e. not in production mode. The online dosage of biocidal chemicals while the system is in production mode is dealt with in Biological Fouling Prevention.
Membrane systems are sanitized in order to keep the number of living microorganisms at an acceptably low level. There are two main reasons why sanitization is required: