Sanitary membrane modules

Sanitary membrane modules these modules have a net outer wrap rather than the standard fiberglass wrap and are sometimes referred to as "full fit" modules... 

High temperatiu-e membranes most standard, high-tem-perature RO membranes are basically the same as sanitary membranes. Ihe majority of high-temperature membrane modules come with a net out wrap (rather than fiberglass) and operate with a bypass (no brine seal) just as the sanitary membrane modules operate. 

Figure 4.33 Sanitary or "full fit" spiral wound membrane module. Courtesy of Dow Water Solutions.

There are special applications where it is required that essentially no dissolution or reaction takes place between the membrane/module material and the process stream. One such application area is food and beverages. For these uses, not only the membrane material but also the housing and gasket materials need to pass certain tests for sanitary reasons (e.g., FDA approval). Stainless steel (especially the 316L type) is typically used as the casing material and fluorinated polymers, EPDM, silicon or other specialty... 

Spirally wound membrane modules can generally meet most process application requirements. They are particularly suitable for sanitary applications in the pharmaceuticals, biotechnology, dairy, food and beverage industries. They are also widely used in the industrial sector for environmental protection, metal coating, chemical and paint apphcations. 

Spiral wound modules are typically covered in fiberglass to protect the leaves (exceptions being sanitary modules, see Chapter 4.4.2.6). Because of the materials of construction (namely the adhesives used) and the potential for "annealing" the membrane, the maximum operating water temperature is limited to 45°C.27... 

There are other types of membrane and modules available. These types spring from applications where the need is different than standard membranes can handle. Two common applications are boron rejection and sanitary processing. 

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