The Status of Research on Constructed Wetlands

Constructed (treatment) wetlands have been state of the art in wastewater treatment technology for decades. Design and operation are determined mainly on the basis of the results of long-term experience. Knowledge of the role of specific removal processes like anaerobic ammonium oxidation, predatory activity of protozoa, bdellovibrio, bacteriophages etc. in the rhizosphere is still insufficient. Basic research is necessary to investigate the transformations involved and to understand the interrelations of element cycles. New findings from research and practice will identify new and expanded applications for highly efficient treatment, particularly of industrial wastewaters. New technologies, such as the combination of wastewater treatment and energy production using "energy" plants, should be the focus of future research. Basic research on element cycle dynamics will help to understand the fundamental processes of greenhouse gas generation in wetlands.