Soft water for Zwijndrecht

Soft water for Zwijndrecht

The delivery of softened drinking water in Zwijndrecht and to an area of Hendrik-Ido-Ambacht has been a much soughtafter wish for many years; both for the inhabitants and for Oasen. Since the end of 2007 concrete plans have been in place. Oasen decided to procure softened drinking water from the water company Evides.

In order to provide Zwijndrecht and the eastern areas of Hendrik-Ido-Ambacht with soft water a new drinking water connection had to be constructed between Dordrecht and Zwijndrecht. To do so the Oude Maas river had to be crossed. Once the new water pipe was realised more than 22,000 households were connected to the soft water.

Numerous parties were involved in the construction of the water pipe, with which Oasen supplied soft water to the inhabitants of Zwijndrecht and the eastern areas of Hendrik-Ido-Ambacht. Oasen was the client, Evides was in charge of project management and Visser & Smit Hanab undertook all the works in its capacity of contractor.

The contract included the design and construction of a DN600 steel drinking water pipe, with a total length of approx. 2,300 metres. Prior to the construction of the new water pipe two horizontally-driven drillings were made under the Oude Maas river, with a length of 1,424 and 624 metres respectively. The pipe depth position was 25 metres under the Normal Amsterdam Water Level (NAP).

Once the pilot hole drilling - from the treatment plant in Zwijndrecht, via the Oude Maas river crossing to Dordrecht - was complete the drill hole was re-drilled (made larger). The pipe was prepared on the Merwede river bank and was transported over the water towards the drill hole (on the Dordrecht side). Next the pipe was drawn into the drill hole.

After the initial, longest drilling, a similar yet smaller drilling followed on the Dordrecht side to link up with the existing Evides network. The first and second pipes were connected by a third. This was realised by means of an open pit after the subsoil had first been sanitised.

The entire project took approx. 10 months.

Click here to see the video about this project.