A second main for a 304 m section was inserted next to the existing sewer because the DN 1,250 concrete main had proven insufficient during heavy rain falls in the past.

Trenchless construction was found to be the best solution for the project, since the existing pipe had to remain in service parallel to the new line.

Engineering company Witteveen and Bos said that jacking pipes were best suited for the trenchless installation method.

The nominal stiffness 3,2000 N/m² was chosen for the DE 1499 mm jacking pipes based on the wall friction of 5 kN/m², and the pipes radius had no effect on the maximal allowable jacking force on the pipe.

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To keep friction during the installation process as low as possible, the pipes were supplied with injection holes for bentonite lubrication.

Although more costly than other construction techniques, the no-dig method was chosen to bypass possible complications such as drainage and poor soil condition.