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Difference between revisions of "Constructed wetlands"

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{{topic header| default.png | Constructed wetlands}}
 
{{topic header| default.png | Constructed wetlands}}
  
A '''constructed wetland''' is an artificial ecosystem growing in a shallow basin, with plants suited to a swampy environment (hydrophytic plants).  
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Constructed wetlands (CW), or artificial wetlands, are engineered wetland ecosystems that have been designed and constructed to use natural wetland processes for the removal of pollutants. These systems mimic marshes with aquatic plants, soil, and associated microorganisms but take advantage of a controlled environment to treat wastewater. Wetlands have shown the ability to meet this goal in an aesthetic, sustainable, and economical manner<ref>Kivaisi, A. K. (2001). The potential for constructed wetlands for wastewater treatment and reuse in developing countries: a review. Ecological Engineering, 16(4), 545–560. doi: http://dx.doi.org/10.1016/S0j925-8574(00)00113-0
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</ref>. However, they require large areas of land, consistent maintenance, and technical operational knowledge.
  
The purpose of the constructed wetland is to deal with a [[wastewater]] stream, such as partially treated sewage or contaminated [[runoff]].  
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==History==
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Natural wetlands have been used as wastewater discharge sites since the beginning of sewage collection. Once their ability to treat water was discovered, as early as the 1950s, early research efforts to use and assess constructed wetlands were begun.(23)Dr. Kathe Seidel at the Max Plankck Institute in Plon, Germany, tested the ability of bulrushes to treat wastewater. Her discoveries led to the first subsurface CW for municipal wastewater treatment in 1974 in the community of Liebenburg-Othfresen, Germany. The first free water surface CW was implemented in The Netherlands in 1967. This system had a star-shaped layout and was called a "planted sewage farm". During the later 20th century, the popularity of CWs grew in Europe and North America. CWs have traditionally been used to treat sewage but, since the late 1980s, have been used to treat a variety of wastewater types such as domestic wastewater, mining and industrial wastewaters, agricultural wastewaters, landfill leachate, stormwater, and runoff.(3)(9) In developing communities, they can be used to treat greywater or used as a secondary treatment for domestic sewage. The main wastewater treatment goal in developing countries is protection of public health through control of pathogens in order to prevent transmission of waterborne diseases and eutrophication of surface waters(22).
  
When used in the final stages of [[wastewater treatment]], their role can be described as "polishing" (raising the water quality from fairly clean to very clean). In [[greywater]] reuse, a constructed wetland is sometimes used for [[greywater treatment|treatment]].
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==Design==
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==Theory==
  
An overlapping term is [[reed beds]], which might be considered a synonym, or a specific type of constructed wetland.{{fact}}
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==Construction==
 
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==Operation and Maintenance==
[[Mosquito control]] should be considered as part of the design. In a balanced ecosystem, there will be predators (such as certain types of fish) to eat the mosquito larvae.
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==Evaluation ==
 
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==Impacts==
THIS IS THE REAL PAGE...
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==Dissemination==
Constructed wetlands (CW), or artificial wetlands, are engineered systems that have been designed and constructed to use natural wetland processes for the removal of pollutants. These systems mimic marshes with aquatic plants, soil, and associated microorganisms but take advantage of a controlled environment to treat wastewater. CWs are used to treat a variety of wastewater types such as domestic wastewater, acid mine drainage, agricultural wastewaters, landfill leachate, urban stormwater, and advanced treated wastewater effluents. (9) In developing communities, they can be used to treat greywater or used as a secondary treatment for domestic sewage. The main wastewater treatment goal in developing countries is protection of public health through control of pathogens in order to prevent transmission of waterborne diseases and eutrophication of surface waters (22).Wetlands have shown the ability to meet this goal in an aesthetic, sustainable, and economical manner<ref>
 
Kivaisi, A. K. (2001). The potential for constructed wetlands for wastewater treatment and reuse in developing countries: a review. Ecological Engineering, 16(4), 545–560. doi: http://dx.doi.org/10.1016/S0j925-8574(00)00113-0
 
</ref>. However, they require large areas of land, consistent maintenance, and technical education for operators.
 
 
 
Natural wetlands have been used as wastewater discharge sites for as long as sewage has been collected. Once their ability to treat water was discovered, as early as the 1950s, they began early research efforts to use and assess constructed wetlands. (23)
 
  
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==Re-Design==
  
  
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* [[Wikipedia:Constructed wetlands]]
 
* [[Wikipedia:Constructed wetlands]]
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==References==
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{{Reflist}}
  
 
== External links ==
 
== External links ==
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[[Category:Sanitation]]
 
[[Category:Sanitation]]
 
[[Category:Constructed wetlands| ]]
 
[[Category:Constructed wetlands| ]]
 
==References==
 
{{Reflist}}
 

Revision as of 03:00, 18 December 2012


Default.png    See also the Constructed wetlands category.
for subtopics, how-tos, project pages, designs, organization pages and more.


Constructed wetlands (CW), or artificial wetlands, are engineered wetland ecosystems that have been designed and constructed to use natural wetland processes for the removal of pollutants. These systems mimic marshes with aquatic plants, soil, and associated microorganisms but take advantage of a controlled environment to treat wastewater. Wetlands have shown the ability to meet this goal in an aesthetic, sustainable, and economical manner[1]. However, they require large areas of land, consistent maintenance, and technical operational knowledge.

History

Natural wetlands have been used as wastewater discharge sites since the beginning of sewage collection. Once their ability to treat water was discovered, as early as the 1950s, early research efforts to use and assess constructed wetlands were begun.(23)Dr. Kathe Seidel at the Max Plankck Institute in Plon, Germany, tested the ability of bulrushes to treat wastewater. Her discoveries led to the first subsurface CW for municipal wastewater treatment in 1974 in the community of Liebenburg-Othfresen, Germany. The first free water surface CW was implemented in The Netherlands in 1967. This system had a star-shaped layout and was called a "planted sewage farm". During the later 20th century, the popularity of CWs grew in Europe and North America. CWs have traditionally been used to treat sewage but, since the late 1980s, have been used to treat a variety of wastewater types such as domestic wastewater, mining and industrial wastewaters, agricultural wastewaters, landfill leachate, stormwater, and runoff.(3)(9) In developing communities, they can be used to treat greywater or used as a secondary treatment for domestic sewage. The main wastewater treatment goal in developing countries is protection of public health through control of pathogens in order to prevent transmission of waterborne diseases and eutrophication of surface waters(22).

Design

Theory

Construction

Operation and Maintenance

Evaluation

Impacts

Dissemination

Re-Design

Constituent Free-Water Surface Subsurface Flow
BOD 93% 93%
TSS 91% 72%
Nitrogen 88% 94%
Phosphorus 53% 65%

How to Size a Free Water Surface Wetland using Kadlec and Knight model

1. Determine the limiting effluent requirements for BOD, nitrogen, or pathogens.

2. Calculate the surface area for BOD, nitrogen, or pathogens using the following equation. The largest surface area will be the control.

[math]A = ((0.0365Q)/(k\lt sub\gt t\lt /sub\gt ))*ln((Ci-C*)/(Ce-C*))[/math]

A is the wetland area required (hectares)


Suggested projects and requested content

Interwiki links

References

  1. Kivaisi, A. K. (2001). The potential for constructed wetlands for wastewater treatment and reuse in developing countries: a review. Ecological Engineering, 16(4), 545–560. doi: http://dx.doi.org/10.1016/S0j925-8574(00)00113-0

External links

  • Constructed wetlands by Bruce Lesikar (Extension Agricultural Engineering Specialist, the Texas A&M University System)