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A '''treatment pond''' treats water fouled by [[Anaerobic organism|anaerobic]] [[bacteria]]. It is used mainly by [[tree nursery|tree nurseries]], [[dairy]] farms and other agricultural companies near horse or cattle [[shed]]s or [[Barn (building)|barn]]s. The pond treats polluted [[stormwater]] and animal [[wastewater]] so that it may be returned to the environment as [[fertilizer]] and [[irrigation]] water.
+
A '''treatment pond''' is a simple [[bioreactor]] for treating [[wastewater]]. It is simply a pond with [[bacteria]] and other [[microorganisms]] from the environment and the wastewater performing the treatment. The bacterial concentration is low compared to other biological treatment processes such as [[activated sludge]], and the treatment time is also longer.  
  
==Uses of treatment ponds==
+
The wastewater may contain organic toxins, sediment, and/or [[anaerobic]] [[bacteria]]. The organic components of the wastewater are converted by the microorganisms (mainly bacteria), producing solids, [[carbon dioxide]] and [[water]]. Solids (including bacterial solids) settle out due to the very slow flow and the shallowness of the water.
A treatment pond may be used in combination with a [[rainwater]] [[reservoir]] to form an ecological, self-purifying irrigation reservoir or swimming pond.<ref>[http://www.oieau.fr/ciedd/contributions/atriob/contribution/russian.htm Ecologic water basins used for agriculture/irrigation]</ref><ref>[http://www.swimpond.com/pools_or_ponds.html reservoirs made self-purifying through addition of treatment pond]</ref> A pond may dispose or treat industrial liquid wastes. An example is the [[Martinez, California]] treatment ponds developed by [[IT Corporation]]. Small-scale treatment can be done in small [[pond]]s if the [[effluent]] is given time to break into harmless nutrients. However, smaller ponds may need to be divided in much the same manner as [[septic tank]]s.
+
  
==Set-up==
+
== Role of treatment ponds ==
{{Cleanup-section|date=January 2009}}
+
===Constructed wetlands===
+
{{See also|Constructed wetland#Set-up of commercial treatment ponds/combined treatment ponds construction in urban areas}}
+
  
===Urban areas===
+
Treatment ponds are used for [[agricultural waste]], and sometimes as part of the processing of waste from [[food production]]. Industrial liquid wastes may be suitable, if there is organic content, but at a low concentration where other forms of biological treatment are inefficient.
[[Image:ReedBedSetUps.jpg|thumb|right|150px|The 3 treatment set-ups mostly employed]]
+
 
Three [[reedbed]] setups are in use. Each are being used in commercial systems (usually together with septic tanks).<ref>[http://www.certipro.be/docs/Certificering%20van%20plantenwaterzuiveringssystemen.pdf reedbed descriptions]</ref> They are:
+
They may also treat polluted [[stormwater]].
 +
 
 +
Depending on the quality of the output, it may be suitable as [[fertilizer]] and [[irrigation]] water.
 +
A treatment pond may be used in combination with a [[rainwater]] reservoir to form a self-purifying irrigation reservoir or swimming pond.<ref>[http://www.oieau.fr/ciedd/contributions/atriob/contribution/russian.htm Ecologic water basins used for agriculture/irrigation]</ref><ref>[http://www.swimpond.com/pools_or_ponds.html reservoirs made self-purifying through addition of treatment pond]</ref> Small-scale treatment can be done in small pond if the [[Glossary_of_sustainability_terms#E|effluent]] is given adequate time to break down the wastewater. Smaller ponds may need to be divided in a similar way to [[septic tank]]s.
 +
 
 +
==Constructed wetlands==
 +
{{main|Constructed wetlands}}
 +
 
 +
A '''constructed wetland''' is a kind of treatment pond with an emphasis on supporting a complex ecosystem within and around the ponds.
 +
 
 +
== Design ==
 +
 
 +
=== Three types of reedbed ===
 +
 
 +
[[File:Treatment-pond-raster.png|thumb|right|150px|The 3 treatment set-ups mostly employed]]
 +
There are three kinds of [[reedbed]] setups. They can be used in commercial systems (usually with septic tanks).<ref>[http://www.certipro.be/docs/Certificering%20van%20plantenwaterzuiveringssystemen.pdf reedbed descriptions]</ref> They are:
 
* Surface flow (SF) reedbeds
 
* Surface flow (SF) reedbeds
 
* Subsurface Flow (SSF) reedbeds
 
* Subsurface Flow (SSF) reedbeds
 
* Vertical Flow (VF) reedbeds
 
* Vertical Flow (VF) reedbeds
  
All three are placed in a closed basin with a substrate. For most commercial purposes (e.g., agriculture) ponds are lined with rubber to ensure being watertight (essential in urban areas). The substrate can be [[gravel]], [[sand]] or [[lavastone]].
+
The reedbeds grow in a closed basin with a substrate medium. For most commercial purposes, ponds are lined in order to be watertight. Rubber can be used. Preventing leakage is essential in urban areas or close to residences. Substrate medium can be [[gravel]], [[sand]] and/or [[lavastone]].
  
==Design Characteristics==
 
 
[[Image:Lavafilter.jpg|thumb|right|250px|A treatment pond aligned next to a [[irrigation]] reservoir, forming a self-purifying reservoir]]
 
[[Image:Lavafilter.jpg|thumb|right|250px|A treatment pond aligned next to a [[irrigation]] reservoir, forming a self-purifying reservoir]]
Surface flow reedbeds use a horizontal flow of waste water between plant roots. They are no longer much used, as they need considerable space (A person requires 20&nbsp;m<sup>2</sup> to purify the water they use.) They have increased smell and poorer purification in winter.<ref name="reedbed secriptions">[http://www.certipro.be/docs/Certificering%20van%20plantenwaterzuiveringssystemen.pdf reedbed secriptions]</ref>
+
In '''surface flow reedbeds''' a horizontal flow carries waste water between the plant roots. They are used much less in recent years, as they need a large area area, around 20&nbsp;m<sup>2</sup> per person for domestic wastewater. In cold weather smell and poorer purification are problems.<ref name="reedbed secriptions">[http://www.certipro.be/docs/Certificering%20van%20plantenwaterzuiveringssystemen.pdf reedbed secriptions]</ref>
  
With subsurface flow reedbeds, the flow of waste water is between plant roots, but not at the water surface. This is more efficient, less smelly and less sensitive to winter conditions. The soil to purify water is 5–10&nbsp;m<sup>2</sup> per person. Intakes, which can clog easily, are a potential problem.<ref name="reedbed secriptions"/>
+
In '''subsurface flow reedbeds''', wastewater flows between plant roots ''below'' the water surface. This is more efficient, requiring 5–10&nbsp;m<sup>2</sup> per person. There is less smell and less sensitivity to cold or winter conditions. Clogging intakes are a potential problem.<ref name="reedbed secriptions"/>
  
Vertical flow reedbeds are similar to subsurface flow reedbeds (subsurface wastewater flow is present here as well). Therefore they have similar efficiency and winter hardiness. Wastewater flow is somewhat different though, as it is vertical. The wastewater is divided at the bottom with the assistance of a [[pump]]. Other than the two previous systems, this system almost makes exclusive use of fine [[sand]] to increase bacteria counts. Intake of oxygen into the water is better. Pumping is done in [[pulse]]s to reduce obstructions with the intakes. Only 3&nbsp;m<sup>2</sup> is needed to purify the water for one person.<ref name="reedbed secriptions"/>
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'''Vertical flow reedbeds''' are similar to subsurface flow reedbeds, and they have similar advantages in efficiency (only 3&nbsp;m<sup>2</sup> is needed per person.<ref name="reedbed secriptions"/>) and cold-weather tolerance. Wastewater flow is vertical, aided by a [[pump]] from the bottom.{{fact}} Vertical reedbeds generally use a fine [[sand]] to allow greater bacterial concentration. Oxygenation of the water is better.{{fact}} Pulsed pumping reduces obstructions in the intakes.  
  
===Organisms===
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=== Organisms ===
{{See also|Organisms used in water purification}}
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Usually, common reed or [[Phragmites|Phragmites australis]] are used in treatment ponds (e.g., in [[greywater treatment]] systems to purify wastewater). In self-purifying water [[reservoirs]](used to purify rainwater), other plants are used as well. These reservoirs need to be filled with 1/4 lavastones and water-purifying plants.<ref>[http://www.stowa-selectedtechnologies.nl/Sheets/Sheets/Lava.Filters.html Overview of lavafilters]</ref>
+
  
Treatment ponds use a wide variety of plants, depending on the local climate and other conditions. Plants are generally chosen which are indigenous, for environmental reasons and optimum performance. In addition to water purifying (de-nutrifying) plants, plants that supply oxygen, and shade are added in ecological water [[drainage basin|catchments]], [[ponds]]. This allows a complete [[ecosystem]]. Local [[bacteria]] and non-[[predator]]y fish may be added to eliminate pests. The bacteria are usually grown by submerging [[straw]] in water and allowing bacteria from the surrounding air to form on it. Plants are divided in four water depth-zones:
+
Common reed ([[Phragmites]]{{w|Phragmites}}) are widely used in treatment ponds (e.g., in [[greywater treatment]] systems to purify wastewater).  
  
# A water depth from 0–20&nbsp;cm. [[Iris pseudacorus]], [[Sparganium|Sparganium erectum]] may be placed here (temperate climates).
+
In self-purifying water [[reservoirs]] (for purifying rainwater prior to distribution), other plants (ie Iris pseudacorus,... )are also used. One approach is to fill the reservoirs with 1/4 lavastones and water-purifying plants.<ref>[http://www.stowa-selectedtechnologies.nl/Sheets/Sheets/Lava.Filters.html Overview of lavafilters]</ref>{{expand}}
# A water depth from 40–60&nbsp;cm. [[Stratiotes|Stratiotes aloides]], [[Hydrocharis|Hydrocharis morsus-ranae]] may be placed here (temperate climates).
+
 
# A water depth from 60–120&nbsp;cm. [[Nymphea|Nymphea alba]], may be placed here (temperate climates).
+
A wide variety of plants are used, and these depending on the local conditions, including climate. Indigenous plants may be preferred for environmental reasons and suitability to the local environment. Plants that supply oxygen and shade are valuable, creating an [[ecosystem]] (=submerged plants). [[Bacteria]] and suitable fish may be added to help eliminate pests. Bacteria may be grown by placing [[straw]] in water and allowing bacteria from the ambient air to grow on it. Plants are divided in four water depth-zones:
# A submerged water depth. [[Myriophyllum|Myriophyllum spicatum]] may be placed here (temperate climates).
+
 
 +
# A water depth from 0–20cm.  
 +
# A water depth from 40–60cm.  
 +
# A water depth from 60–120cm.  
 +
# Deeper water
  
 
Three non-predatory fish (surface, bottom and ground-swimmers) are chosen. This ensures the fish 'get along'. Examples for temperate climates are:
 
Three non-predatory fish (surface, bottom and ground-swimmers) are chosen. This ensures the fish 'get along'. Examples for temperate climates are:
  
* Surface swimming fish: [[Leuciscus leuciscus]], [[Leuciscus idus]], and [[Scardinius erythrophthalmus]]
+
* Surface swimming fish
* Middle-swimmers: [[Rutilus rutilus]]
+
* Middle-swimmers
* Bottom-swimming fish: [[Tinca tinca]]
+
* Bottom-swimming fish
  
The plants are usually grown on [[coconut]] fibre.<ref>[http://www.lukmertens.be/kwekerij.html Coconut growing medium used for water purifying plants]</ref> At the time of implantation to water-purifying ponds, de-nutrified soil is used to prevent growth of [[algae]] and other unwanted [[organisms]]
+
[[Coconut]] fibre.<ref>[http://www.lukmertens.be/kwekerij.html Coconut growing medium used for water purifying plants]</ref> can be used as a growing medium for propagating the plants.
  
==Finishing==
+
The use of de-nutrified soil can prevent growth of [[algae]] and other unwanted [[organisms]]
These systems, for example, aerate the water after the final reedbed using cascades such as flowforms before holding the water in a shallow pond.<ref>[http://www.sheepdrove.com/article.asp?art_id=115] reedbed and flowform cascade polishing, Sheepdrove Organic Farm, England</ref> Primary treatments such as [[septic tanks]], and pumps such as [[grinder pump]]s may be added.<ref>[http://www.pure-milieutechniek.be/Page22.htm Pictures of hybrid reedbed systems]</ref>
+
 
 +
:''See also [[Wikipedia:Organisms used in water purification]]
 +
 
 +
=== Finishing ===
 +
 
 +
A final, shallow "polishing pond" is often used. Aeration can be carried out with cascades before passing into the final pond, or with mechanical aerators within the ponds.<ref>[http://www.sheepdrove.com/article.asp?art_id=115] reedbed and flowform cascade polishing, Sheepdrove Organic Farm, England</ref>  
 +
 
 +
=== Combined systems ===
 +
 
 +
Primary treatments such as [[anaerobic digesters]] or [[septic tanks]] may be used for the initial stages of treatment where [[biochemical oxygen demand]] is sufficiently high. [[Grinder pumps]] may be used before treating a lumpy effluent, to create a slurry which is more easily processed by the bacteria.
  
 
==Rooftop treatment ponds==
 
==Rooftop treatment ponds==
Rooftop water purifying ponds are being used on rooftops. These [[green roof]]s can be built from a simple substrate (as is being done in Dongtan)<ref>[http://www.eukn.org/eukn/themes/Urban_Policy/Urban_environment/Environmental_sustainability/dongtan-eco-city_1348.html Dongtan green roofs filter water]</ref> or with plant-based ponds (as is being done by WaterWorks UK Grow System).<ref>[http://www.wwuk.co.uk/grow.htm WWUK rooftop water purification with plants]</ref> Waterzuiveren.be<ref>[http://www.waterzuiveren.be/concepten/dakvijvers Waterzuiveren.be building water-purifying roofponds]</ref> Plants used include [[calamus]], Menyanthes trifoliata, Mentha aquatica, ...<ref>[http://www.toontoelen.be/index.php?option=com_content&task=view&id=684&Itemid=58 Description of plants used in water-purifying rooftop ponds]</ref>
 
  
==See also==
+
Rooftop water purifying ponds can be built using a simple substrate, as is being done in the Dongtan eco-city.<ref>[http://www.eukn.org/eukn/themes/Urban_Policy/Urban_environment/Environmental_sustainability/dongtan-eco-city_1348.html Dongtan green roofs filter water]</ref>
*[[Detention pond]]
+
 
*[[Retention pond]]
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Plant-based ponds have also been designed for roofs,<ref>[http://www.toontoelen.be/index.php?option=com_content&task=view&id=684&Itemid=58 Description of plants used in water-purifying rooftop ponds]</ref> e.g. WaterWorks UK Grow System)<ref>[http://www.wwuk.co.uk/grow.htm WWUK rooftop water purification with plants]</ref> and Waterzuiveren of Belgium{{fact}}<ref>[http://www.waterzuiveren.be/concepten/dakvijvers Waterzuiveren.be building water-purifying roofponds]</ref>
*[[Settling pond]]
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 +
== See also ==
 +
*[[AT CAD Team/AT settlement water distribution system|AT settlement water distribution system]]
 +
*[[Greywater treatment]]
 +
*[[Constructed wetlands]]
 +
 
 +
== Gallery ==
 +
<gallery>
 +
File:AT_Vertical_Flow_reedbed.png|A simple reed bed
 +
</gallery>
  
==External links==
+
== External links ==
{{wikipedia p|Treatment pond}}
+
* [[Wikipedia:Treatment pond]]
 
* [http://www.facstaff.bucknell.edu/kirby/4ponds.html Pictures of a treatment pond]
 
* [http://www.facstaff.bucknell.edu/kirby/4ponds.html Pictures of a treatment pond]
  
 
==References==
 
==References==
{{Cleanup-link rot|date=January 2009}}
 
 
{{Reflist}}
 
{{Reflist}}
  
{{DEFAULTSORT:Treatment Pond}}
 
 
[[Category:Anaerobic digestion]]
 
[[Category:Anaerobic digestion]]
 
[[Category:Sewerage infrastructure]]
 
[[Category:Sewerage infrastructure]]
 
[[Category:Water treatment]]
 
[[Category:Water treatment]]

Latest revision as of 05:14, 16 July 2013

A treatment pond is a simple bioreactor for treating wastewater. It is simply a pond with bacteria and other microorganisms from the environment and the wastewater performing the treatment. The bacterial concentration is low compared to other biological treatment processes such as activated sludge, and the treatment time is also longer.

The wastewater may contain organic toxins, sediment, and/or anaerobic bacteria. The organic components of the wastewater are converted by the microorganisms (mainly bacteria), producing solids, carbon dioxide and water. Solids (including bacterial solids) settle out due to the very slow flow and the shallowness of the water.

Role of treatment ponds[edit]

Treatment ponds are used for agricultural waste, and sometimes as part of the processing of waste from food production. Industrial liquid wastes may be suitable, if there is organic content, but at a low concentration where other forms of biological treatment are inefficient.

They may also treat polluted stormwater.

Depending on the quality of the output, it may be suitable as fertilizer and irrigation water. A treatment pond may be used in combination with a rainwater reservoir to form a self-purifying irrigation reservoir or swimming pond.[1][2] Small-scale treatment can be done in small pond if the effluent is given adequate time to break down the wastewater. Smaller ponds may need to be divided in a similar way to septic tanks.

Constructed wetlands[edit]

A constructed wetland is a kind of treatment pond with an emphasis on supporting a complex ecosystem within and around the ponds.

Design[edit]

Three types of reedbed[edit]

The 3 treatment set-ups mostly employed

There are three kinds of reedbed setups. They can be used in commercial systems (usually with septic tanks).[3] They are:

  • Surface flow (SF) reedbeds
  • Subsurface Flow (SSF) reedbeds
  • Vertical Flow (VF) reedbeds

The reedbeds grow in a closed basin with a substrate medium. For most commercial purposes, ponds are lined in order to be watertight. Rubber can be used. Preventing leakage is essential in urban areas or close to residences. Substrate medium can be gravel, sand and/or lavastone.

A treatment pond aligned next to a irrigation reservoir, forming a self-purifying reservoir

In surface flow reedbeds a horizontal flow carries waste water between the plant roots. They are used much less in recent years, as they need a large area area, around 20 m2 per person for domestic wastewater. In cold weather smell and poorer purification are problems.[4]

In subsurface flow reedbeds, wastewater flows between plant roots below the water surface. This is more efficient, requiring 5–10 m2 per person. There is less smell and less sensitivity to cold or winter conditions. Clogging intakes are a potential problem.[4]

Vertical flow reedbeds are similar to subsurface flow reedbeds, and they have similar advantages in efficiency (only 3 m2 is needed per person.[4]) and cold-weather tolerance. Wastewater flow is vertical, aided by a pump from the bottom.[verification needed] Vertical reedbeds generally use a fine sand to allow greater bacterial concentration. Oxygenation of the water is better.[verification needed] Pulsed pumping reduces obstructions in the intakes.

Organisms[edit]

Common reed (PhragmitesW) are widely used in treatment ponds (e.g., in greywater treatment systems to purify wastewater).

In self-purifying water reservoirs (for purifying rainwater prior to distribution), other plants (ie Iris pseudacorus,... )are also used. One approach is to fill the reservoirs with 1/4 lavastones and water-purifying plants.[5]please expand

A wide variety of plants are used, and these depending on the local conditions, including climate. Indigenous plants may be preferred for environmental reasons and suitability to the local environment. Plants that supply oxygen and shade are valuable, creating an ecosystem (=submerged plants). Bacteria and suitable fish may be added to help eliminate pests. Bacteria may be grown by placing straw in water and allowing bacteria from the ambient air to grow on it. Plants are divided in four water depth-zones:

  1. A water depth from 0–20cm.
  2. A water depth from 40–60cm.
  3. A water depth from 60–120cm.
  4. Deeper water

Three non-predatory fish (surface, bottom and ground-swimmers) are chosen. This ensures the fish 'get along'. Examples for temperate climates are:

  • Surface swimming fish
  • Middle-swimmers
  • Bottom-swimming fish

Coconut fibre.[6] can be used as a growing medium for propagating the plants.

The use of de-nutrified soil can prevent growth of algae and other unwanted organisms

See also Wikipedia:Organisms used in water purification

Finishing[edit]

A final, shallow "polishing pond" is often used. Aeration can be carried out with cascades before passing into the final pond, or with mechanical aerators within the ponds.[7]

Combined systems[edit]

Primary treatments such as anaerobic digesters or septic tanks may be used for the initial stages of treatment where biochemical oxygen demand is sufficiently high. Grinder pumps may be used before treating a lumpy effluent, to create a slurry which is more easily processed by the bacteria.

Rooftop treatment ponds[edit]

Rooftop water purifying ponds can be built using a simple substrate, as is being done in the Dongtan eco-city.[8]

Plant-based ponds have also been designed for roofs,[9] e.g. WaterWorks UK Grow System)[10] and Waterzuiveren of Belgium[verification needed][11]

See also[edit]

Gallery[edit]

External links[edit]

References[edit]