Editing Ultrafiltration (section)

== Applications ==
Industries such as [[chemical manufacturing|chemical]] and [[pharmaceutical industry|pharmaceutical]] manufacturing, food and beverage processing, and [[waste water treatment]], employ ultrafiltration in order to recycle flow or add value to later products. Blood [[Kidney dialysis|dialysis]] also utilizes ultrafiltration.{{cn|date=September 2023}}

=== Drinking water ===
[[Image:Ultrafiltration Grundmühle.jpg|thumb|Drinking water treatment 300&nbsp;m<sup>3</sup>/h using ultrafiltration in Grundmühle waterworks (Germany)]]
Ultrafiltration can be used for the removal of particulates and macromolecules from raw water to produce potable water. It has been used to either replace existing secondary (coagulation, flocculation, sedimentation) and tertiary filtration (sand filtration and chlorination) systems employed in water treatment plants or as standalone systems in isolated regions with growing populations.<ref>{{cite journal|last1=Clever|first1=M.|author2=Jordt, F. |author3=Knauf, R. |author4=Räbiger, N. |author5=Rüdebusch, M. |author6= Hilker-Scheibel, R. |title=Process water production from river water by ultrafiltration and reverse osmosis|journal=Desalination|date=1 December 2000|volume=131|issue=1–3|pages=325–336|doi=10.1016/S0011-9164(00)90031-6|bibcode=2000Desal.131..325C }}</ref> When treating water with high suspended solids, UF is often integrated into the process, utilising primary (screening, flotation, filtration) and some secondary treatments as pre-treatment stages.<ref>{{cite journal|last=Laîné|first=J.-M.|author2=Vial, D. |author3=Moulart, Pierre |title=Status after 10 years of operation — overview of UF technology today|journal=Desalination|date=1 December 2000|volume=131|issue=1–3|pages=17–25|doi=10.1016/S0011-9164(00)90002-X|bibcode=2000Desal.131...17L }}</ref> UF processes are currently preferred over traditional treatment methods for the following reasons:<br />
:*No chemicals required (aside from cleaning)
:*Constant product quality regardless of feed quality
:*Compact plant size
:*Capable of exceeding regulatory standards of water quality, achieving 90–100% pathogen removal<ref>{{cite book|author=American Water Works Association Research Foundation ... Ed. group Joël Mallevialle|title=Water treatment membrane processes|year=1996|publisher=McGraw Hill|location=New York [u.a.]|isbn=9780070015593}}</ref>
UF processes are currently limited by the high cost incurred due to membrane fouling and replacement.<ref>{{cite journal|last1=Edwards|first1=David|author2=Donn, Alasdair |author3=Meadowcroft, Charlotte |title=Membrane solution to a "significant risk" Cryptosporidium groundwater source|journal=Desalination|date=1 May 2001|volume=137|issue=1–3|pages=193–198|doi=10.1016/S0011-9164(01)00218-1|bibcode=2001Desal.137..193E }}</ref> Additional pretreatment of feed water is required to prevent excessive damage to the membrane units.

In many cases UF is used for pre filtration in [[reverse osmosis]] (RO) plants to protect the RO membranes.{{cn|date=September 2023}}

=== Protein concentration ===
UF is used extensively in the dairy industry;<ref>{{cite journal |last1=Villecco F., Aquino R.P., Calabrò V., Corrente M.I., D’Amore M., Grasso A., Naddeo V. |title=Fuzzy-assisted ultrafiltration of whey by-products recovery |journal=Euro-Mediterranean Journal for Environmental Integration |year=2020 |volume=5 |issue=1 |page=8 |doi=10.1007/s41207-019-0138-5 |bibcode=2020EMJEI...5....8V |s2cid=212655195 }}</ref> particularly in the processing of cheese whey to obtain [[whey protein concentrate]] (WPC) and lactose-rich permeate.<ref name=Tamime>{{cite book|last=Tamime|first=A. Y.|title=Membrane Processing Dairy and Beverage Applications.|date=12 December 2012|publisher=Wiley|location=Chicester|isbn=978-1118457023}}</ref><ref name=Nigam>{{cite journal|last1=Nigam|first1=Mayank Omprakash|author2=Bansal, Bipan |author3=Chen, Xiao Dong |title=Fouling and cleaning of whey protein concentrate fouled ultrafiltration membranes|journal=Desalination|date=1 January 2008|volume=218|issue=1–3|pages=313–322|doi=10.1016/j.desal.2007.02.027|bibcode=2008Desal.218..313N }}</ref> In a single stage, a UF process is able to concentrate the whey 10–30 times the feed.<ref name=HB>{{cite book|last=Cheryan|first=Munir|title=Ultrafiltration and Microfiltration Handbook|year=1998|publisher=CRC Press|isbn=1420069020}}</ref><br />
The original alternative to membrane filtration of whey was using steam heating followed by drum drying or spray drying. The product of these methods had limited applications due to its granulated texture and insolubility.  Existing methods also had inconsistent product composition, high capital and operating costs and due to the excessive heat used in drying would often denature some of the proteins.<ref name=Tamime /><br />
Compared to traditional methods, UF processes used for this application:<ref name=Tamime /><ref name=HB />
:*Are more energy efficient
:*Have consistent product quality, 35–80% protein product depending on operating conditions
:*Do not denature proteins as they use moderate operating conditions
The potential for fouling is widely discussed, being identified as a significant contributor to decline in productivity.<ref name=Tamime /><ref name=Nigam /><ref name=HB /> Cheese whey contains high concentrations of calcium phosphate which can potentially lead to scale deposits on the membrane surface. As a result, substantial pretreatment must be implemented to balance pH and temperature of the feed to maintain solubility of calcium salts.<ref name=HB /><ref>Ann-Sofi Jönsson, Gun Trägårdh,
Ultrafiltration applications,
Desalination,
Volume 77,
1990,
Pages 135-179,
ISSN 0011-9164,
https://doi.org/10.1016/0011-9164(90)85024-5</ref>
[[Image:ultra filtration.JPG|thumb|right|200px|A selectively permeable [[Membrane (selective barrier)|membrane]] can be mounted in a [[Laboratory centrifuge|centrifuge tube]]. The [[buffer solution|buffer]] is forced through the membrane by [[centrifugation]], leaving the [[protein]] in the upper chamber.]]

=== Other applications ===
:*Filtration of effluent from paper pulp mill
:*Cheese manufacture, see [[ultrafiltered milk]]
:*Removal of some bacteria from milk
:*Process and waste water treatment
:*Enzyme recovery
:*Fruit juice concentration and clarification
:*[[Kidney dialysis|Dialysis]] and other blood treatments
:*Desalting and solvent-exchange of proteins (via [[diafiltration]])
:*Laboratory grade manufacturing
:*Radiocarbon dating of bone collagen
:*Recovery of electrodeposition paints
:*Treatment of oil and latex emulsions
:*Recovery of lignin compounds in spent pulping liquors