Project Haarlemmermeer

Steel instead of cast iron
The Rijnland Water Board is working on the renovation and expansion of the treatment plant in Zwanenburg. This is necessary to continue sustainably purifying the increasing amount of wastewater in the future. As a subcontractor to the main contractor Mobilis, A.Hak is executing all the underground piping work on the site of the wastewater treatment plant on IJweg. And that’s not without reason. A.Hak specializes in laying pipes with large diameters, as evidenced by the story of work preparer Nick Verboven. Nick describes his colleagues in the field as ‘large pipe specialists’.

You don’t lay the pipes for the inlet and outlet to the new booster pit and the associated Y-pieces every day, he says. “The Y-pieces provide the transition between pipe sections of DN 1600 and DN 1800.

The pipes are so large that you can stand upright inside them. For the specialists, it’s a great work challenge, with pipe sections of such large dimensions.” And that’s not without reason. A.Hak specializes in laying pipes with large diameters, as evidenced by the story of work preparer Nick Verboven. Nick describes his colleagues in the field as ‘large pipe specialists’.

Transition between pipe sections
You don’t lay the pipes for the inlet and outlet to the new booster pit and the associated Y-pieces every day, he says. “The Y-pieces provide the transition between pipe sections of DN 1600 and DN 1800. The pipes are so large that you can stand upright inside them. For the specialists, it’s a great work challenge, with pipe sections of such large dimensions.”

Quality assured
A.Hak is involved from the very beginning in the production and delivery. At every new step in the process, the suppliers keep A.Hak informed of the status of the pipe sections, so that any deviations are detected at an early stage and the quality of the Y-pieces and the piping is ultimately assured. Even now that the pipes are on site, they are being checked again. Nick: “We always look at it with multiple eyes. And because experienced colleagues Peter and Piet are always watching, we as younger colleagues also learn more about the trade and what to pay attention to.”

Nick hopes that A.Hak will have completed the installation of the piping in the booster pit by the end of the year. Due to the expansion at the Zwanenburg wastewater treatment plant, A.Hak has already installed a bypass pipe (DN 1200 steel) from the effluent pit to the surface water. “We are also going to work on a DN100 pipe from Distribution Work 2 to Settling Tank 7, which we are laying on sleepers with a buoyancy bracket due to the soft ground. We applied the same principle to the bypass. We are also making a DN 600 pipe and a DN 800 pipe between the new sewage sludge pumps. It’s really fantastic work.”