Working in a white world

The flatbed trailers and other heavy equipment had to pass over that to reach the intended construction site smoothly and safely. The spot where Van Schie was to build a drilling rig, somewhere deep in the meadows of the Horstermeerpolder.

The Horstermeerpolder has a problem. The polder suffers from extreme salinization. This is bad for agriculture, industry, drinking water and nature. While the water in the other polders and natural areas in the area is fresh, brackish seepage water is increasingly rising in the Horstermeer.

The salty groundwater is old seawater that entered the subsoil when the sea had free rein here some seven thousand years ago. The polder itself is 2.5 meters below sea level.

And underneath that polder is a big bubble of brackish water. Especially in the center, it is already surfacing in the ditches. Waternet, the company that produces drinking water not only for the wider area but also for the city of Amsterdam, recently developed a revolutionary method for turning this brackish water into clean drinking water. To find out if this works, test wells are now being drilled.

Strong platform

Frank Smits, engineer at Waternet, explains why the exploratory drilling must be done from a stable platform: ‘We are drilling 230 meters deep (!) through all kinds of layers. We also go right through a very deep clay layer and don’t know what’s underneath. Probably a lot of water. Chances are.

And when that comes up with great pressure, we have to be firm with our plant. Also, the whole borehole can become unseated due to the pressure and we are in the middle of the gunk with all our equipment.

Van Schie has experience in this type of work and has previously built platforms for various types of drilling. Here in Nederhorst, the platform is constructed from a combination of uniflote pontoons and treadway bridge sections. The demand for clean drinking water has grown tremendously in recent years. Partly because of the many data centers that have been added in recent years, especially around Amsterdam. Water is used to cool their equipment.

Waternet can hardly meet the demand anymore. Therefore, it would be a huge boost if the desalination of the Horstermeerpolder will succeed. Especially since it is very pure water. It is only salt, so there are no drug residues, metals or pesticides in it, like elsewhere in the Netherlands. The drilling was carried out by soil drilling company Haitjema B.V.