The construction of the RWZI Harnaschpolder involved a new development of 20 buildings and 33 concrete tanks. The tank diameters vary from 18 to 64 metres. The average height of the inner and outer walls are between 4 and 9 metres. The sludge tanks have the highest walls and are approximately 20 metres tall.

A total of approximately 12,350 concrete piles were driven into the ground, made from 90,000 m2 of concrete. The total building cost of this project was € 250 million and this was the largest installation in the Netherlands at the time. Van den Bersselaar supplied the covers for four primary sedimentation tanks, numerous staircases, stairs and railings, and is still involved in ongoing maintenance work.



Contract value


Smart Steel Solutions!

Jos van den Bersselaar Construction BV is an independent steel construction company. We specialise in light constructions for numerous applications and with a high level of finishing. For 58 years, we have delivered products, such as stairs, balustrades, canopies, sound barriers and bridge railings, to clients in the infrastructure and utilities sectors, industry and waste water.

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