Under construction since 2015, the project replaced the original primary sedimentation and aeration basins with new anaerobic digesters and a combined heat and power plant. The new facility now produces around 78 GWh of electricity and 82 GWh of heat from biogas, meaning the plant will be able to generate all the energy it requires for wastewater treatment, with energy to spare, while reducing Vienna’s annual carbon emissions by 40,000 tonnes.
At the center of the upgraded plant are six 30-meter high digesters, each capable of generating biogas from 12’500 cubic meters of sludge. Sulzer delivered the mixer units for the digester tanks to keep the biogas production running optimally. In contrast to conventional equipment, Sulzer’s solution required smaller motors, thus unlocking energy savings. In addition, Sulzer’s turbocompressors delivered further savings, cutting total power consumption by 400 kW, while reducing noise and offering very low maintenance costs.