"NL: "What to do with residual water, because we still don’t know"

Johan van Cappelle is the cultivation specialist at Dutch nursery Sjaak van Schie, where potted hydrangeas is the main product. The potted plant company has three branches in the Westland. The company has not yet decided what to do with the residual water after January 1.

Nursery Sjaak van Schie has 6 hectares of greenhouses in Naaldwijk, in Maasdijk 5,5 hectares of greenhouses and 30 hectares of field for the propagation of young plants. In Portugal there is another branch with reproductive plants for the cuttings.

For greenhouse cultivation, rainwater is collected in silos. The greenhouse company in Maasdijk has water storage for 2,500 m³ and in Naaldwijk for 1.500 m³. In case of water shortage, tap water is used as supplement. In the Maasdijk branch there is a concrete floor with an ebb and flood system, but the potted plants can also be supplied with water from above. In the Naaldwijk branch, there is an ErfGoed Floor and the potted plants are showered from above. In both locations, excess water is discharged through a drainage system to a return water silo and re-used as irrigation water without disinfection.

Approximately 2,000 m3 of residual water is discharged in the sewer for each location annually. That water must be purified from plant protection products by 1 January 2018. "We are looking at three options. We can purchase two purification plants, which require a few hundred thousand in investment, we participate in the water treatment collective Oranjepolder or we have the water cleaned by mobile purification," says Johan van Cappelle, who is a member of the Water Business Group of LTO Glaskracht Nederland. "We have not reached any conclusion yet. It is possible that next year we will initially use mobile purification of the residual water and only then decide for collective purification or investment in our own purification plants."

The cultivation specialist: "With the purification plants we want to extract the fertilizers so that, at the same time, we are ready for cultivation without emission in 2027. A module to remove sodium is not necessary because hydrangeas can be grown well with a high sodium content."