Goed Gietwater (demo)

Location: Westland, The Netherlands


Provincie Zuid-Holland
Hoogheemraadschap Delfland


Currently the different businesses use groundwater to irrigate the crops, but the salinity of the groundwater in the western part of The Netherlands is increasing. This means that expensive desalination technology would need to be applied that also produces a brine that causes environmental harm. It is expected that new policies will prohibit the disposal of brine within the next 5-10 years. This is an additional incentive to look for alternative sources of irrigation water. Hence there is a need to look at alternative fresh water sources to irrigate the crops.

Tailor-made effluents can be a reliable source of irrigation water year round! The increased water security of supply that effluents offer compared to groundwater can be another good reason switch sources. Options for the treatment and reuse of municipal wastewater (from the RWZI – Harnashpolder and the AWZI – De Groote Lucht) have been explored mostly from a technical standpoint.  It is unclear however, how the system design should look like: which water treatment technologies should be selected and especially where the pipeline corridors and storage options can best be located in the area.

AquaVest to identify the optimal system design at lower CAPEX

We built a demo for the project to showcase how the different variables interact and determine the optimal system solution. In other words, how the (seasonal) demand for irrigation water from the greenhouses, the OPEX of the RO units, the sales prices of the crops, the timing of the legislation on brine disposal, and the available effluents from the RWZI and AWZI all play out. The CAPEX and OPEX of a number of investment options were defined, and by running a number of scenarios AquaVest produced an investment strategy to transition towards a more sustainable use of water that also improves the water security for the horticulture sector in Westland.


SDG12: Responsible consumption and production

  • Treatment and reuse of municipal wastewater as alternative source of irrigation water
  • Reduced groundwater extraction (reduced subsidence and soil salinization)

SDG13: Climate action

  • Create a reliable source of irrigation water to improve security of supply during drought periods
  • Improved collaboration between the public sector and the horticulture sector

SDG14: Life below water

  • Reduced brine disposal leads to improved groundwater and surface water quality
  • Reduced groundwater extraction improves the area’s water balance