Siemens will support the city of Vienna in optimizing its main sewage plant in terms of energy. For this purpose, Siemens is supplying the control, measuring, analytical and power distribution systems, as well as the low-voltage and medium-voltage switchgear.
Furthermore, the order includes the installation and commissioning of the individual systems. The order is worth around $25 million and is part of "E_OS 2020" (Energy Optimization Sludge Treatment), the largest environmental project ever undertaken by the city of Vienna.
As from 2020, the main sewage plant will use sewage gas to generate autonomously all the energy required for the wastewater treatment. For the sewage treatment itself, a particularly efficient method is used with reduced water content and double the solid content.
This considerably reduces the energy consumed during anaerobic digestion and gas generation. The main sewage plant, which currently is among the largest energy consumers in the community, should generate an output of 78 GWh of electricity and 82 GWh of thermal energy. In total this method should save about 40,000 metric tons of CO2 per year.
The order includes the migration and expansion of the existing Simatic PCS 7 process control system to the latest Version 8.1. The conversion work is taking place in parallel with normal operations. All functions are tested already in the engineering phase with the Simit simulation software, enabling quality to be assured and commissioning times to be shortened.
In addition, Siemens is supplying Sitrans process instrumentation, devices for gas analysis (Ultramat/Oximat), as well as Scalance network components, including cabling, installation and commissioning. For a safe, high-availability power supply to about 450 motors and drives in the sewage plant, Siemens is installing a redundant 20 kV medium-voltage power distribution system of the type NXAir (28 fields), Sivacon S8 low-voltage power distribution systems (about 80 fields), a busbar trunking system and 14 transformers.
The protection devices of the existing systems and those of the new systems are equipped by Siemens with Ethernet-based communication interfaces. The redundant SICAM AK 3 station control technology processes all data points from the energy supply and delivers these to the higher-level switchgear control technology and subsequently for the overall monitoring of the new process control system.