Many European countries have recently stated an increasing demand for small waste water treatment plants. Constructed wetlands seem to be particularly well suited for on-site treatment due to their simple construction and large buffering capacity.

A number of different designs exist in Europe, above all subsurface flow systems, which have been in use for 20 years. At first, horizontal flow was preferred but the stringent legal rules have led to the development of highly efficient vertical flow in recent years. In order to meet the higher requirements of small and very sensitive recipients, combined systems (i.e. constructed wetlands and conventional biological plants) have proved to be successful. At present, tests are being carried out to study the use of constructed wetlands for other applications as well, such as the treatment of groundwater, industrial waste water and sludge dewatering.

All our present know-how and experience with constructed wetlands should enable us to convince the authorities and to obtain legal permission for the installation of constructed wetlands.