A very special project was implemented by the Muhr municipality in Lungau/Salzburg with its new sewage system. The project had been approved and the corresponding framework conditions created several years ago: the collection of all domestic waste water in the fully-biological treatment plant of the RHV at St. Michael in Lungau.
The main drain runs for part of its course along the main road, and was installed without any problems. With a slope of over 100%, the planning and installation proved to be more difficult in the Jedl district. This steep stage lies in rock, which could only be bypassed with a great deal of effort and cost. From the many planning variants, it was decided to opt for the bolder course of the drain, and rather take it 150 m through an already existing power station utility tunnel, and thus through the mountain, than make a wide detour or construct a pumping station.
It was to be a low-cost drain with plaster sections in the shafts. The tunnel, which was only emptied for the purposes of photography, is normally permanently flooded to a height of 1.60 m. Originally planned in PVC, the material soon came up against its limits, when it came to passing the steep sections with a tension- and thrust-proof connection, in order to guarantee the absolute integrity of the pipe when surrounded by water. A reliable and economical solution was found in the form of TRM pipes.
Detailed information
Pipes: VRS ductile sewage pipes
Nominal width: DN 200
Lenght: 750 m
Planning: Kohlhofer Civil Engineers, Salzburg
