Inorganic Fouling or Scaling

Inorganic fouling or scale formation at the membrane surface results from the increased concentration of one or more inorganic salts such as CaCOj, CaS04, 2H2O, and Ca3(P04)2 beyond their solubility limits and their ultimate precipitation onto the membranes [8]. 

Precipitation fouling may be defined as the phenomenon of a solid layer deposition on a heet transfer surface, primarily as a result of the presence of dissolved inorganic salts in the flowing solution which exhibit supersaturation under the process conditions. Deposits formed under various conditions have different mechanical characteristics. The term "scaling" is generally used to describe a dense crystalline deposit, well bonded to the metal surface. It is often associated with the crystallization of salts of inverse solubilities under heat transfer conditions. When the deposited layer is porous and loosely adherent, it is described by terms such as "soft scale," "powdery deposit," or "sludge."... 

Inorganic compounds that may precipitate and scale or foul the membranes (such as iron and manganese, calcium carbonate, calcium sulfate, barium sulfate, or silica)... 

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