Constructed wetlands are a natural alternative to technical methods of wastewater treatment.
However, our understanding of the complex processes caused by the plants, microorganisms, soil matrix
and substances in the wastewater, and how they all interact with each other, is still rather incomplete.
In this article, a closer look will be taken at the mechanisms of both plants in constructed wetlands
and the microorganisms in the root zone which come into play when they remove contaminants from
wastewater. The supply of oxygen plays a crucial role in the activity and type of metabolism
performed by microorganisms in the root zone. Plants’ involvement in the input of oxygen into the
root zone, in the uptake of nutrients and in the direct degradation of pollutants as well as the role of
microorganisms are all examined in more detail.