|style="width:50%;"|{{santable_new|
sys1=[[Single Pit System |1]]|
sys2=[[Blackwater Treatment System with Infiltration|56]]|sys3=[[Blackwater Treatment System with SewerageEffluent Transport|67]]|sys4=[[Blackwater Transport to (Semi-) Centralized Treatment System |78]]|sys5=[[Sewerage System with Urine Diversion |89]]|
sys6=|
sys7=|
ManShared=|
ManPublic=XX|
Input1=Blackwater|Input2=Greywater |Input3= Brownwater | Input4= |Input5=|Output1= Effluent | Output2= Treated Sludge | Output3= Biogas | Output4= | Output5=
|english_link=Upflow_Anaerobic_Sludge_Blanket_Reactor
|french_link=Digesteur_anaérobie_à_flux_ascendant
[[Image:Icon_upflow_anaerobic_sludge_blanket_reactor.png |right|80px]]
'''The Upflow Anaerobic Sludge Blanket Reactor upflow anaerobic sludge blanket reactor (UASB) is a single tank process. Wastewater enters the reactor from the bottom, and flows upward. A suspended sludge blanket filters and treats the wastewater as the wastewater flows through it.'''
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The sludge blanket is comprised of microbial granules(1 to 3 mm in diameter), i.e. , small agglomerations (0.5 to 2mm in diameter) of microorganisms that, because of their weight, resist being washed out in the upflow. The microorganisms in the sludge layer degrade organic compounds. As a result, gases (methane and carbon dioxide) are released. The rising bubbles mix the sludge without the assistance of any mechanical parts. Sloped walls deflect material that reaches the top of the tank downwards. The clarified effluent is extracted from the top of the tank in an area above the sloped walls.
After several weeks of use, larger granules of sludge form which , in turn , act as filters for smaller particles as the effluent rises through the cushion of sludge. Because of the upflow regime, granule-forming organisms are preferentially accumulated as the others are washed out.
===Design Considerations=== Critical elements for the design of UASB reactors are the influent distribution system, the gas-solids separator, and the effluent withdrawal design. The gas that rises to the top is collected in a gas collection dome and can be used as energy (biogas). An upflow velocity of 0.6 7 to 0.9m1 m/h must be maintained to keep the sludge blanket in suspension. Primary settling is usually not required before the UASB.
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===AdequacyAppropriateness===A UASB is not appropriate for small or rural communities without a constant water supply or electricity. The technology is relatively simple to design and build, but developing the granulated sludge may take several months. The UASB reactor has the potential to produce higher quality effluent than Septic Tanks (S.9), and can do so in a smaller reactor volume. Although it is a well-established process for large-scale industrial wastewater treatment and high organic loading rates up to 10 kg BOD/m3/d, its application to domestic sewage is still relatively new.
A UASB It is not appropriate often used for small or rural communities without a constant water supply or electricity. A skilled operator is required to monitor brewery, distillery, food processing and repair the reactor pulp and paper waste since the pump in case process typically removes 80 to 90% of problemsCOD. Although Where the technology influent is simple to design and buildlow strength or where it contains too many solids, proteins or fats, it the reactor may not work properly. Temperature is also a key factor affecting the performance. or fats, the reactor may not well proven for domestic wastewater, although new research work properly. Temperature is promisingalso a key factor affecting the performance.
===Health Aspects/Acceptance=== The UASB reactor has the potential to produce higher quality effluent than Septic Tank|septic tanks]], operators should take proper health and can do so safety measures while working in a smaller reactor volume. Although it is a wellestablished process for large-scale industrial wastewater treatment processesthe plant, its application to domestic sewage is still relatively newsuch as adequate protective clothing. Typically it is used for brewery, distillery, food processing Effluent and pulp sludge still pose a health risk and paper waste since the process can typically remove 85% to 90% of Chemical Oxygen Demand (COD). Where the influent is low strength, the reactor may should not work properly. Temperature will also affect performancebe directly handled.
===Health Aspects/AcceptanceOperation & Maintenance=== The UASB is a centralized treatment Centralized Treatment technology that must be operated and maintained by professionals. As with all wastewater processesA skilled operator is required to monitor the reactor and repair parts, e.g., pumps, operators should take proper health and safety measures while working in the plantcase of problems. ===Maintenance=== Desludging is infrequent and only excess sludge is removed once every 2 to 3 years. A permanent operator is required to control and monitor the dosing pump.
===References===
* Lettinga, G., Roersma, R. and Grin, P. (1983). Anaerobic Treatment of Raw Domestic Sewage at Ambient Temperatures Using a Granular Bed UASB Reactor. Biotechnology and Bioengineering 25 (7): 1701-1723. (The first paper describing the process)
* Critesvon Sperling, RM. and Tchobanoglousde Lemos Chernicharo, GC. A. (19982005). [http://books.googleBiological Wastewater Treatment in Warm Climate Regions, Volume One.com/books/about/Small_and_decentralized_wastewater_manag.html?id=yx9SAAAAMAAJ Small and decentralized wastewater management systems]. WCB and McGraw-HillIWA Publishing, New YorkLondon, USAUK. * Lettinga, Gpp., Roersma, R. and Grin, P741-804. (1983Detailed design information). :Available at: [http://onlinelibrarywww.wileyiwawaterwiki.com/doi/10org iwawaterwiki.1002/bit.260250703/abstract Anaerobic Treatment of Raw Domestic Sewage at Ambient Temperatures Using a Granular Bed UASB Reactororg]. Biotechnology and Bioengineering 25 (7): 1701–1723. The first paper describing the process.
* SasseTare, LV. and Nema, A. (1998n.d.). UASB Technology – Expectations and Reality. United Nations Asian and Pacific Centre for Agricultural Engineering and Machinery, Beijing, CN. (Assessment of UASB installations in India):Available at: [http://www.indiawaterportalunapcaem.org/sites/indiawaterportalunapcaem.org/files/Decentralised_%20wastewater_%20treatment_%20in_%20developing_%20countries_A_%20handbook_%20by_%20BORDA_1998.pdf DEWATS: Decentralised Wastewater Treatment in Developing Countries]. BORDA, Bremen Overseas Research and Development Association, Bremen, Germany.
* von SperlinTchobanoglous, MG., Burton, F. L. and de Lemos ChernicharoStensel, CAH. D. (20052004). [httpWastewater Engineering://wwwTreatment and Reuse, Metcalf & Eddy, 4th Ed.iwapublishing(Internat.com/pdf/contents/isbn1843390027_contentsEd.pdf Biological Wastewater Treatment in Warm Climate Regions]). Volume One. IWAMcGraw-Hill, LondonNew York, US. pp 741–804. 1005-1016. (Detailed description and design information.)
* TareUlrich, VA. (Ed. and Nema), Reuter, AS. (nEd.d), Gutterer, B. (Ed. [http://unapcaem), Sasse, L.org/Activities%20Files/A01/UASB%20Technology%20%E2%80%93%20Expectations%20and%20Reality, Panzerbieter, T.pdf UASB Technology-expectations and reality]Reckerzügel, T. [http://unapcaem(2009).org United Nations Asian Decentralised Wastewater Treatment Systems (DEWATS) and Pacific Centre for Agricultural Engineering and Machinery]Sanitation in Developing Countries. A Practical Guide. Assessment of UASB installations in IndiaWEDC, Loughborough University, Leicestershire, UK.(Short overview)
* Vigneswaran, S., et alBalasuriya, B. L. N. and Viraraghavan, T. (1986). [http://books.google.com/books/about/Anaerobic_Wastewater_Treatment.html?id=NIJJcgAACAAJ Environmental Sanitation Reviews: . Anaerobic Wastewater Treatment- – Attached growth Growth and sludge blanket process]Sludge Blanket Process. Environmental Sanitation Information Center, AIT, Bangkok, ThailandTH. (Good technical overview – Chapter 5 provides a good technical overview.)
===Acknowledgements===
{{:Acknowledgements Sanitation}}