Hybrid systems are a combination of different types of constructed wetlands in order to achieve improved treatment efficiencies. This can be specifically interesting for enhancing nitrogen removal rates.
VSSF CW's have proven to provide good conditions for nitrification. HSSF CW's on the other hand show more anaerobic conditions necessary for denitrification. A free water surface wetland covered with floating macrophytes can optimize plant uptake. But also in these systems anaerobic conditions will dominate.
Different layouts can be designed taking into account the characteristics of the wastewater and the removal efficiencies that have to be met.
Using hybrid systems it is also possible to create zero discharge systems.
with free-floating macrophytes
planted with trees