Perhaps this is what they mean? It is a natural means of water treatment after all.

HTH

Sheila

# Le lagunage est une technique naturelle d’épuration des eaux basée sur l’eutrophisation, considérée comme une filtration naturelle par des micro-organismes, des algues et des plantes aquatiques.
fr.wikipedia.org/wiki/Lagunage

# Traitement biochimique : stockage de l’eau résiduaire durant le temps nécessaire à la production de la dégradation de la matière organique par bactéries hétérotrophes. Les lagunes sont constituées de plans d’eau peu profonds, en général au nombre de trois. ...
www.b-harmony.com/savoir/eau/eau_glossaire.htm

# Procédé d'épuration des eaux usés mettant en application le reproduction du phénomène naturel d'auto-épuration en l'accélérant.
www.syndic-rivieres.org/lexiq.htm


Sewage treatment - Wikipedia, the free encyclopedia
In the mechanical treatment, the influx (influent) of sewage water is strained ... Lagooning provides settlement and further biological improvement through ...
en.wikipedia.org/wiki/Sewage_treatment - 80k - Còpia en memòria - Pàgines semblants
Water treatment - Wikipedia, the free encyclopedia
Water treatment describes the processes used to make water more acceptable ... or biological such as lagooning, slow sand filtration or activated sludge. ...
en.wikipedia.org/wiki/Water_treatment - 18k - Còpia en memòria - Pàgines semblants


Water treatment describes the processes used to make water more acceptable for a desired end-use. These can include use as drinking water, for use in industrial processes or to allow discharge into the environment without adverse ecological impact. These processes may be physical such as settlement, chemical such as disinfection or coagulation or biological such as lagooning, slow sand filtration or activated sludge.

http://en.wikipedia.org/wiki/Water_treatment





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Note added at 10 mins (2006-11-23 15:52:06 GMT)
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Lagooning

Lagooning provides settlement and further biological improvement through storage in large man-made ponds or lagoons. These lagoons are highly aerobic and colonization by native macrophytes, especially reeds, is often encouraged. Small filter feeding invertebrates such as Daphnia and species of Rotifera greatly assist in treatment by removing fine particulates.


http://en.wikipedia.org/wiki/Sewage_treatment#Lagooning

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Note added at 20 mins (2006-11-23 16:02:09 GMT)
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Ponding or lagooning is also mentioned here:

e) Natural-biological treatment technologies: all the methodologies and processes not included in "Conventional treatment", but used as well to treat wastewater. The final results achieved by the specified non conventional techniques can be compared, on the base of the characteristic of the outcoming water, to the treatment level in conventional processes, i.e. secondary-tertiary level. The methodologies included in this part are characterised by lower cost but higher land area need.

Processes included and codes:

Waste Stabilization Ponds (WSP): are also called 'waste stabilisation lagoons, because the organic substances in the wastewater are converted to more stable (less degradable) forms. Ponding or lagooning is effective in treating wastewater and can reduce Biological Oxygen Demand and Suspended Solids to the same levels as mechanical treatment plants (e.g. Activated Sludge Treatment). In addition because of the longer residence time of wastewater in the lagoon (in the order of days), removal of pathogenic bacteria and viruses by natural die-off is greater than in an AS treatment plant (residence time of the order of hours). Cysts of parasites and helminth eggs are also usually removed through sedimentation in the lagoons.

http://www.fao.org/landandwater/aglw/waterquality/treatproc....