What: purifying water to irrigation water for greenhouses
Where: Delft en Westland
Who: Hoogheemraadschap van Delfland, Delfluent Services B.V., Evides Industriewater,
When: started in 2010
Source: Delft Blue Water

Delft Blue Water

The availability of sufficient quantities of high-quality fresh water is essential for food production. At present, many greenhouse horticulture companies in the Netherlands use rain water, insofar as it is available, or pump up brackish groundwater. Rain water, however, is not free of contaminants, especially near big cities and along the coast. Brackish groundwater must be desalinated before being used by means of RO (Reverse Osmosis). In this case, a salty residual flow (brine) is created, which is then returned to the soil. In the near future, it is likely that restrictions will be placed on returning brine to the soil, or that it will even be banned outright. For this reason, Delft Blue Water – a consortium of three partners – launched a demonstration study to produce water reliably, sustainably and cost-effectively using innovative technologies. Under the name Delft Blue Water, waste urban water is purified and transformed into Class I irrigation water for greenhouse horticulture.

Reliable, sustainable and cost-effective water. The Harnaschpolder treatment plant in Den Hoorn (Netherlands) cleans the waste urban water from the Hague region. At present, the purified water is discharged into the North Sea. Under the name Delft Blue Water (DBW), a study is being conducted to determine whether the purified water can be put to good use. Using innovative technologies, we are investigating how we can produce both surface water and high-quality irrigation water for greenhouse horticulture reliably, sustainably and cost-effectively using purified urban water as the source.

Demonstration project

In the Westland demonstration nursery, a 180 m² greenhouse has been set up to test the suitability of the DBW irrigation water for greenhouse horticulture. Tomatoes are grown in this greenhouse, some of which are supplied with rain water and some with DBW irrigation water. The two water systems are completely separate from each other, and each has its own disinfector and dosing system. The recirculation also takes place in separate systems. An independent research company closely monitored the water quality. In addition, they followed the development of the plant and the tomato in terms of crop growth, production, plant health and food safety. The practical test was successful: there is no difference between tomatoes that receive surface water and those that are supplied with Delft Blue Water irrigation water. Watch the video and explanation here: http://www.youtube.com/watch?v=U5iquZVWlh4