Ultrafiltration is a low-pressure membrane process used to separate bacteria, viruses, and high  molecular weight compounds colloidal and particulate matters from a feed stream.  Ultrafiltration has larger pores and high permeability with less osmotic effects that allows ultrafiltration to operate at relatively lower pressure than nanofiltration and reverse osmosis  and is therefore it is least costly to operate. 

Ultrafiltration is widely used in industry as pretreatment for other forms of purification such as  ion exchange and reverse osmosis, gelatin and protein concentration in the pharmaceutical  industry, sugar clarification in the food and beverage industry, cheese and whey concentration,  production of ultra pure water, clarification of juice, downstream processing, membrane  bioreactors, treatment of bleach plant effluents, and recovery of lignin compounds in the pulp  and paper industry. Ultrafiltration can be used to reject virus, bacteria, pyrogens, endotoxins,  and particulates but not ionic species. 

Hollow fiber configuration is widely used in the ultrafiltration processes. The benefit of this  construction is that it allows for backwashing of the membrane when the filtrate or product  flow rate has decreased due to accumulation of material on the membrane. The ultrafiltration  membrane is capable of removing colloidal materials, fine suspensions, bacteria, virus,  suspended material and large dissolved molecular weight organic materials. 

Advantages of UF over Conventional Media Filtration 

∙ Improved product quality 

∙ Product SDI typically less than 1 

∙ Removal of virus, and bacteria 

∙ Removal of microbiological matter 

∙ Removal of colloidal matter 

∙ Colloidal Silica Reduction 

∙ Improvement of downstream Reverse Osmosis (RO) performance ∙ Consistently treated water quality irrespective of changes in feed water quality 

Applications of Ultrafiltration 

∙ Pretreatment to RO system (brackish and seawater applications) ∙ Purification of surface and well water for potable applications 

∙ Filtration of industrial water 

∙ Membrane Bio-Reactor 

∙ Wastewater recycle and reuse