Upflow anaerobic sludge blanket digestion

Upflow anaerobic sludge blanket digestion

Upflow Anaerobic Sludge Blanket (UASB) technology, normally referred to as UASB reactor, is a form of anaerobic digester that is used in the treatment of wastewater.

The UASB reactor is a methanogenic (methane-producing) digester that evolved from the anaerobic clarigester. A similar but variant technology to UASB is the expanded granular sludge bed (EGSB) digester. A diagramatic comparison of different anaerobic digesters can be found [http://www.fao.org/docrep/t0541e/T0541E02.gifhere] .

UASB uses an anaerobic process whilst forming a blanket of granular sludge which suspends in the tank. Wastewater flows upwards through the blanket and is processed (degraded) by the anaerobic microorganisms. The upward flow combined with the settling action of gravity suspends the blanket with the aid of flocculants. The blanket begins to reach maturity at around 3 months. Small sludge granules begin to form whose surface area is covered in aggregations of bacteria. In the absence of any support matrix, the flow conditions creates a selective environment in which only those microorganisms, capable of attaching to each other, survive and proliferate. Eventually the aggregates form into dense compact biofilms referred to as "granules" [ [http://www.uasb.org/discover/granules.htm#granules What are sludge granules? UASB Homepage] ] . A picture of anaerobic sludge granules can be found [http://www.uasb.org/discover/granules.htm#figure1 here] .

Biogas with a high concentration of methane is produced as a by-product, and this may be captured and used as an energy source, to generate electricity for export and to cover its own running power. The technology needs constant monitoring when put into use to ensure that the sludge blanket is maintained, and not washed out (thereby losing the effect). The heat produced as a by-product of electricity generation can be reused to heat the digestion tanks.

The blanketing of the sludge enables a dual solid and hydraulic (liquid) retention time in the digesters. Solids requiring a high degree of digestion can remain in the reactors for periods up to 90 days [ [http://www.alexmarshall.me.uk/index_files/documents/HarrogateProceedings.pdf ArrowBio Process] Finstein, M. S., Zadik, Y., Marshall, A. T. & Brody, D. (2004) The ArrowBio Process for Mixed Municipal Solid Waste – Responses to “Requests for Information”, Proceedings for Biodegradable and Residual Waste Management, Proceedings. (Eds. E. K. Papadimitriou & E. I. Stentiford), Technology and Service Providers Forum, p. 407-413 ] . Sugars dissolved in the liquid waste stream can be converted into gas quickly in the liquid phase which can exit the system in less than a day.

UASB reactors are typically suited to dilute waste water streams (3% TSS with particle size >0.75mm).

ee also

*Anaerobic digestion
*Anaerobic digester types
*Anaerobic clarigester
*Ecological sanitation
*Environmental technology
*Anaerobic filter
*Expanded granular sludge bed digestion
*Hybrid reactor (combination of UASB and an anaerobic filter (AF))
*Fluidized bed reactor
*Mechanical biological treatment
*Sewage treatment

External links

* [http://www.austep.com/ Austep: Anaerobic Granular Sludge Bed Technology supplier]
* [http://www.uasb.org/ Anaerobic Granular Sludge Bed Technology Pages] - a site about anaerobic bioreactor systems for wastewater treatment and sustainable environmental technology.
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12397675&dopt=Abstract Upflow anaerobic sludge blanket reactor--a review.] - (highly technical)


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Expanded granular sludge bed digestion — An expanded granular sludge bed (EGSB) reactor is a variant of the UASB concept [ [http://www.uasb.org/discover/agsb.htm#egsb UASB and EGSB] Field, J. (2002) Anaerobic granular sludge bed technology pages, anaerobic granular sludge bed reactor… …   Wikipedia

  • Anaerobic digestion — and regenerative thermal oxidiser component of Lübeck mechanical biological treatment plant in Germany, 2007 …   Wikipedia

  • Anaerobic digester types — The following is a partial list of different types of anaerobic digesters. These processes and systems harness anaerobic digestion for purposes such as sewage treatment and biogas generation.Examples include: *Anaerobic activated sludge process… …   Wikipedia

  • Sewage sludge treatment — described the processes used to manage and dispose of the sludges produced during sewage treatment.ources of sludgeCoarse primary solids and secondary biosolids accumulated in a wastewater treatment process must be treated and disposed of in a… …   Wikipedia

  • List of waste water treatment technologies — The following page consist of a list of waste water treatment technologies: * Activated sludge systems [ [http://www.oost vlaanderen.be/docs/nl/gc/35447.%20afvalwaterzuivering%20op%20landbouwbedrijven.pdf Overview of activated sludge system with… …   Wikipedia

  • Sequencing batch reactor — Sequencing batch reactors (SBR) or sequential batch reactors are industrial processing tanks for the treatment of wastewater. SBR reactors treat waste water such as sewage or output from anaerobic digesters or mechanical biological treatment… …   Wikipedia

  • List of waste management topics — This page has a list of waste management topics:*Anaerobic digestion *ArrowBio *Autoclave *Best management practice for water pollution (BMP) *Bioaccumulation *Biodegradability prediction *Biodegradation *Biodrying *Biogas *(Biogas powerplant:… …   Wikipedia

  • List of waste management acronyms — The following article contains a list of acronyms used in the waste management industry. [ [http://www.ciwm.co.uk/mediastore/FILES/11384.doc Waste management jargonyms] CIWM website, Accessed 9/11/06] [ [http://www.environment… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.