Joint International Conference on Long-term Experiments ...

characterized by marshy plants like the common reed, sedge and the rush. These plants
are also present today, but unfortunately in a small number.
Related to the characteristics of the soil we have to mention that in this area we can
find chemozem, but the oxygen poor soils with an important content of clay are
dominating the area (general characteristics of the marshes). The sandy soil can also be
found in some places, but that is not characteristic.
Wastewater treatment with constructed wetlands
The wastewater purification with constructed wetlands is not a very new water cleaning
technology. It has already been used since the 60’, when some German scientists
discovered the purification capacity of the natural wetlands, and after that the idea of
wastewater cleaning with plants was spread all of the word. Nowadays, in Hungary
many systems like that are working and their efficiency is really high. The reduction of
P, NOx, NH3, K, metals, phenols and other elements can compete in many cases with
the classic wastewater treatment systems.
The wetlands are very successful wastewater purification systems all over the
world, and they are very various. They can be characterized by many criteria, as their
genesis, location, functioning.
By their genesis wetlands can be:
• Marshes
• Bugs
• Flood area
• Marginalized wetlands
• Periodic wetlands
From another point of view they can be natural or artificial wetlands, lakes or marshes,
and some of them are complex piped systems, with a surface or a subsurface flow. In
these complex systems the input wastewater generally enters in the pipe lines flowing
through under the root zone of the plants (generally common reed), and after that is
evacuated in the nature. At this time the water has to be cleaned and purified.
The technology that is going to be used depends on the situation of the villages, the
number of residents, the composition and quantity of the wastewater, external factors as
climate, type of the soil and many other factors. The origin of the wastewater is another
criterion that has to be taken into consideration in order to select the suitable methods,
because there is a significant difference between the wastewaters coming from
communal, industrial or agricultural use.
The system of constructed wetlands is based on the absorption process of the
pollutants by the emergent, submersed and floating plants, using the biofilters created
under the water surface, and in that way the toxic elements are going to be eliminated
from the water.
There exist more physical, chemical and biological processes that make the
treatment efficient. These processes generally are the following: sedimentation,
filtration, adsorption and absorption, biological decomposing, and there are many other
processes that assure together a complex purification.
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