Open House at the Oosthuizen Wastewater Treatment Plant on April 18

On Saturday, April 18, 2026, the Hollands Noorderkwartier Water Board (HHNK) is hosting an open house at the wastewater treatment plant in Oosthuizen. Between 10:00 a.m. and 3:00 p.m., visitors can see for themselves how wastewater is treated and how HHNK uses the new Nereda technology in this process. 

The open house offers residents of the region a unique opportunity to see how the water that flows into the sewer system every day is treated and returned to surface water. HHNK staff will lead tours and explain how the treatment process works and what innovations have been implemented in recent years. 

Interactive activities 

Visitors can look forward to an informative and interactive programme. For example, they can: 

look through a microscope to see all the creatures living in the water;
experience how water treatment works using virtual reality (VR).
There will be a scavenger hunt for the children during the tour.

Sign up 

We ask visitors to register in advance via:

The tour begins at Restaurant La Mère Anne: Dorpsweg 110, 1631 DJ Oudendijk.