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Constructed wetlands

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

A constructed wetland is an artificial ecosystem growing in a shallow basin, with plants suited to a swampy environment (hydrophytic plants).

The purpose of the constructed wetland is to deal with a wastewater stream, such as partially treated sewage or contaminated runoff.

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 treatment.

An overlapping term is reed beds, which might be considered a synonym, or a specific type of constructed wetland.[verification needed]

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.

THIS IS THE REAL PAGE... 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[1]. 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)

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

External links

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


  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