Ultrafiltration sewage treatment

Membrane-retained components are collectively called concentrate or retentate. Materials permeating the membrane are called filtrate, ultrafiltrate, or permeate. It is the objective of ultrafiltration to recover or concentrate particular species in the retentate (eg, latex concentration, pigment recovery, protein recovery from cheese and casein wheys, and concentration of proteins for biopharmaceuticals) or to produce a purified permeate (eg, sewage treatment, production of sterile water or antibiotics, etc). Diafiltration is a specific ultrafiltration process in which the retentate is further purified or the permeable sohds are extracted further by the addition of water or, in the case of proteins, buffer to the retentate. 

Ultrafiltration processes are used to recover or concentrate a particular species in the retentate, as is exemplified by latex concentration, or to obtain a purified permeate as in sewage treatment. Ultrafiltration is a means of cold sterilization for many heat-sensitive liquids whose sterilization could not be carried out earlier. Thus, in the food industry draft beer provides an interesting example of a product whose feasibility as a commercial beverage has been an outcome of ultrafiltration cold sterilization by ultrafiltration retains the esters on account of which the beer has its draft flavour. Similarly, ultrafiltration plays a key role in the pharmaceutical industry for the commercial-scale preparation of sterile water and antibiotics. 

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