User:Milton Beychok/Sandbox: Difference between revisions

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An '''aerated basin''' is a holding and/or treatment [[pond]] provided with artificial [[aeration]] to promote the biological [[oxidation]] of [[wastewater]]s.<ref>{{cite book |author=Middlebrooks, E.J., et al.|title=Wastewater Stabilization Lagoon Design, Performance and Upgrading|edition= |publisher=McMillan Publishing| year=1982|isbn=0-02-949500-8}}</ref><ref>{{cite book|author=Tchobanoglous, G., Burton, F.L., and Stensel, H.D.|title=Wastewater Engineering (Treatment Disposal Reuse) / Metcalf & Eddy, Inc.|edition=4th|publisher=McGraw-Hill Book Company|year=2003|isbn=0-07-041878-0}}</ref><ref>{{cite book | author=Beychok, Milton R. | title=[[Aqueous Wastes from Petroleum and Petrochemical Plants]] | edition=1st | publisher=John Wiley & Sons | year=1967 | id= [[LCCN]] 67019834}}</ref> There are many other biological processes for treatment of wastewaters, for example [[activated sludge]], [[trickling filter]]s (also called biofilters) and  [[Trickling_filter#Types_of_large-scale_trickle_filters|rotating biological contactors]]. They all have in common the use of [[oxygen]] (or air) and [[Microbe|microbial]] action to biotreat the pollutants in wastewaters.


==Types of aerated basins==
There are many methods for aerating a lagoon or basin:
* Motor-driven floating surface aerators
* Motor-driven submerged aerators
* Motor-driven fixed-in-place surface aerators
* Injection of compressed air through submerged diffusers
===Floating surface aerators===
[[Image:Surface-Aerated Basin.png|thumb|right|300px|A Typical Surface-Aerated Basing (using motor-driven floating aerators)]]
Ponds or basins using floating surface aerators achieve 80 to 90% removal of [[BOD]] with retention times of 1 to 10 days.<ref name=Basin>{{cite journal|author=Beychok, M.R.|year=1971|month=|title=Performance of surface-aerated basins|journal=Chemical Engineering Progress Symposium Series|volume=67|issue=107|pages=322–339|issn=}} [http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=ENV&recid=7112203&q=&uid=788301038&setcookie=yes Available at CSA Illumina website]</ref> The ponds or basins may range in depth from 1.5 to 5.0 metres.<ref name=Basin/>
In a surface-aerated system, the aerators provide two functions: they transfer air into the basins required by the biological oxidation reactions, and they provide the mixing required for dispersing the air and for contacting the reactants (that is, oxygen, wastewater and [[microbes]]). Typically, the floating surface aerators are rated to deliver the amount of air equivalent to 1.8 to 2.7&nbsp;kg [[Oxygen|O<sub>2</sub>]]/[[kW]]h. However, they do not provide as good mixing as is normally achieved in activated sludge systems and therefore aerated basins do not achieve the same performance level as activated sludge units.<ref name=Basin/>
Biological oxidation processes are sensitive to temperature and, between 0 °C and 40 °C, the rate of biological reactions increase with temperature. Most surface aerated vessels operate at between 4 °C and 32 °C.<ref name=Basin/>
==References==
{{reflist}}
==External links==
* [http://www.lagoonsonline.com Wastewater Lagoon Systems in Maine]
* [http://www.epa.gov/owm/mtb/apartlag.pdf Aerated, Partial Mix Lagoons] (Wastewater Technology Fact Sheet by the [[United States Environmental Protection Agency‎|U.S. Environmental Protection Agency‎]])
* [http://www.ces.clemson.edu/ees/rich/technotes/index.html Aerated Lagoon Technology] (Linvil G. Rich, Professor Emeritus, Department of Environmental Engineering and Science, [[Clemson University]])
==See also==
* [[Industrial wastewater treatment]]
* [[List of waste water treatment technologies]]
* [[Retention basin]]
* [[Rotating biological contactor]]
* [[Sewage treatment]]
* [[Water pollution]]

Revision as of 00:00, 22 January 2010

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