Coöperatieve Tuinbouw Water Zuivering de Vlot is a wastewater treatment facility located at ‘s- Gravenzande treating 160 hectares (60 companies) of wastewater from greenhouses mainly growing ornamental crops. Exploring water and nutrient reuse oppurtunities for their facility, they are optimizing their system for internal symbiosis within their own facility and external symbiosis with neighbouring greenhouses and industries. De Vlot has ambitions to reach zero liquid discharge and provide symbiotic internal and potentially external reuse of water and nutrients from greenhouse wastewater (approx. 10% of the total water input). The system to treat and reuse drainwater from 60 greenhouses (160 ha) is laid out maximum capacity of 60 m3/h but the expectation is that the majority of the time, 40 m3/h is sufficient (for one out out 3 treatment streets to be in maintenance if required). In this setup, recycling would be provided internally for the greenhouses in the summer and in the winter months the excess recovered water and nutrients can be reuse in nearby industries or a central water bank.
In the case study the following technologies are investigated:
1) use of electrodialysis for treatment of greenhouse wastewater - specifically selective sodium removal - to produce a water quality fit for irrigation purposes
2) feasibility of high-temperature aquifer thermal energy storage (HT-ATES) to balance heat supply and demand across the year.