In Demokwekerij Westland the ‘Delft Blue Water’ project is currently running. The project examines whether rainwater purified by the Harnaschpolder Purifier in Den Hoorn (Westland) can be used as high quality irrigation water for greenhouses. This process could kill two birds with one stone. Residual water from the sewage treatment plant can be put to good use and greenhouse growers have a new sustainable water source. The project is a collaboration between Delfland Water Board, Evides, LTO Grow Service, Priva, TNO, Groen Agro Control and Demokwekerij Westland. In addition, an advisory committee of growers has been appointed to supervise the project.
The purified water is normally discharged to the North Sea. The project developed techniques with which water is purified to the extent that it can be used as drinking water. In a special test greenhouse researchers examine if the water can be applied to the growing of tomatoes. Part of the greenhouse gets rainwater as irrigation water, the other part gets 'Delft Blue Water'. Both water systems remain completely separated. Recirculation takes place through separate systems with their own dosing. Quality and development are closely monitored. This month the first results are expected.
Today, a lot of greenhouse growers make use of rainwater. The disadvantage is that rainwater is not always available and contains sodium. Sodium may cause growth inhibition in the crop. The use of brackish water pumped up from the soil isn’t always beneficial either. The Delft Blue Water project could be a welcome solution.
Source: Proeftuin Zwaagdijk
