The canton of Zurich decided to build a central sewage sludge incineration plant for sludge from all the canton’s sewage treatment plants on the site of the Werdhölzli sewage treatment plant, with a capacity of 100,000 tonnes of dewatered sewage sludge per year. The implementation was to be carried out by a sole contractor, i.e. by a general contractor who was also responsible for implementation planning. The entire implementation period lasted just two years!

TBF not only supported the client in the referendum (yes-vote 94%!), but also handled all the planning work including the sole contractor tender. The aim was to identify the minimum specifications, but with the right boundary conditions, as well as decisive selection criteria for the sole contractor evaluation. During the implementation phase, TBF ensured that the requirements set were consistently implemented. The Werdhölzli sewage sludge incineration plant is still regarded as a model project by many future sewage sludge incinerators and has many visitors as a result.