Constructed wetland systems provide high quality water treatment
at relatively low cost. The benefits of a constructed wetland for
wastewater treatment include the following:
They achieve stringent water quality standards and are effective
at removing nutrients such as nitrogen and phosphorous. They are
relatively tolerant to changes in hydraulic and biological rates.
They help protect groundwater and surface water resources.
The simplicity of design results in inexpensive capital, maintenance
and operational costs by non-technical personnel. Less energy is
required to operate the wetland, which results in increased reliability.
They help reduce erosion. They provide natural habitat for wildlife,
create an aesthetic landscape amenity, and may be used for outdoor
recreation and education.
The wetland system should be inspected every six months. It provides
of a wide variety of on-site labor. The most common types of reported
work are pulling out undesirable plant species, removing dead vegetation
and accumulated organic matter, cleaning of pipes, replanting, and
fertilizing.
Despite all the benefits of a wetland treatment system, the technology
still faces some obstacles. One such obstacle is our inability to
control and predict every outcome for the wetland treatment. Technology
assessment research has been conducted to increase our understanding,
but biologic and hydrologic processes are less predictable than
standard treatment. Also, problems with pests and pathogens are
possible. The engineering uncertainty, added with the threat of
professional liability, could result in deterrence. Another concern
is the constructed wetland size and volume, which may become a major
obstacle particularly in an urban setting.
In addition to the problems mentioned, there are also some institutional
constraints regarding blackwater wetland development. Constructed
wetlands do not fit handily into existing planning regulatory definitions.
There exists neither national guidance nor uniform acceptance of
them by state agencies. In the state of Washington for instance,
constructed wetlands are considered an 'experimental technology.'
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