Hydropower plants developed by the Austrian company VA Tech Hydro use sewage water to generate power in treatment plants in France, Jordan, and Switzerland.
VA Tech Hydro’s Valloire Project in the Alps, near Col du Galibier, is the first hydropower plant in France designed to extract energy from untreated sewage water. This innovative project uses raw water from the village that is transported into the valley where a single jet horizontal Pelton unit economically dissipates the 650-m water column before entering the treatment plant.
The Valloire is well known for skiing in the winter and the Tour de France in the summer.
Along with the success of VA Tech’s projects in Jordan and Switzerland, this project should open new horizons to many more ski resorts in the Alps with similar conditions.
Hydro energy can be found in a number of diverse locations, such as treatment plants in the Jordan desert, or in the valleys below a ski resort, as at Valloire in France. The only requirement, as with any other hydro plant, is an economical combination of head and flow.
VA Tech’s pioneering project at Le Châble, Switzerland, first introduced this type of hydro turbine in 1992 when engineers installed a horizontal 700-kW Pelton unit at Le Châble, using energy from the untreated sewage water at the famous ski resort of Verbier.
The first use of this technique was a challenge, using a 447-m head. The project overcame some tough problems that arose during its initial installation. Concerns were raised over the wear and tear of the mechanical resistance of the runner and nozzle since untreated water contains solid elements. Another concern was the corrosion resistance, as untreated water also contains H2S acid, which destroys carbon steel within weeks. Design engineers overcame both problems by using highly valuable Duplex stainless steel and adequate ceramic coating. Consequently, the unit has been in operation for 12 years.
