Inagro builds a constructed wetland inspired by examples of Aarhus University
From idea to design
Twelve hectares of new fields for trials were taken into use in 2018. The fields will be used for research on open air horticulture, therefore the availability of irrigation water is important. Hence a pond collecting irrigation water has been installed. Fields have been drained as well and excess of drainage water is collected into the reservoir for irrigation water. The outlet of this reservoir flows into the constructed wetland.
Design of the constructed wetland
The wetland consists of three parts. Each part has a shallow retention basin with a 0,70 m water column depth followed by a sand bank on which reeds will grow. For the second part of the constructed wetland, Inagro still has to decide: either drainage water will directly be discharged into the surface water, or drainage water will flow to a shallow drainage system for some extra denitrification.
Design of woodchip basin
Because it was impossible to discharge the drainage water derived from the lowest part of the field towards the pond, a woodchip basin has been installed as a second denitrificaton system to treat this part of the drainage water.
The construction of the wetland started up in the autumn of 2019. The construction of the woodchip will take place this winter. The performance of both systems will be evaluated by monitoring nitrate concentrations at the inlet and outlet of each system.