Many successful companies in the private sector have flown the flag of innovation. Also the public sector welcomes innovation, as has been proved by the operators of the Flos sewage treatment plant in Wetzikon in the Zurich Oberland. They invest some 350,000 Swiss francs every year into projects with the Mure in mind and, thanks to an efficient operations management, have been able to lower their charges at the same time.

Prepared for future challenges

Specific projects for the next few years include the extension of the thermal power station to make use of the biogas generated during the anaerobic digestion of the sewage sludge, as well as new solutions for the transportation of the sewage sludge. In the pipeline also are plans for a fifth stage of the treatment process for the separation of micropollutants. Sooner or later, the operators of sewage treatment plants will be faced with tight limits for nanoparticles. The Fies plant will be ready when it happens. “This is an explosive topic” explained Operations Manager Markus Sobaszkiewicz, “because the effects of nanotechnology on the environment are still largely unknown.”

Innovative sliding gate valve technology

Markus Sobaszkiewicz is convinced that the challenges of the future will only be overcome by using innovative technologies. It just needs the courage to go down new paths today. He and his team stick to this philosophy consistently when it comes to renovating existing parts of the plant, such as the modification of the aeration tank. Conventional pneumatic gate valves were previously used in this area for the control of the oxygen supply. These could not provide the required degree of control accuracy. Therefore, replacing these units with just another conventional product was no option. As Markus Sobaszkiewicz explains: “We took our problem to Bachofen (sales agency for Schubert & Salzer Control Systems in Switzerland), who surprised us, out of nowhere so to speak, with an unconventional proposal to solve the issue of controlling the O2 supply. The specialists in the Fluid Control and Pneumatics Department recommended that we install pioneering sliding gate valves which should significantly reduce energy consumption.”

Maximum savings in energy consumption

The operations manager took a keen interest in the idea. After a joint visit to one of Bachofen‘s customers who was already using this technology, he made the firm decision to take a chance on an unconventional solution. The result proved him right: “By using those unique sliding gate valves, it‘s now possible to control the air requirement for optimal microorganism action with a maximum deviation of one percent, a precision we‘ve never achieved before.” The effect of the new solution on energy consumption is substantial. The operator of the Flos plant was able to say with satisfaction that, compared with measurements taken the previous year, energy consumption had dropped by five to ten percent. And there is still scope for making more savings, according to Markus Sobaszkiewicz.

Flos town drainage sewage plant - Sewage treatment for the town of Wetzikon and five other communities, as well as the maintenance and operation of all of the town‘s sewers and special plants, and the Bäretswil and Aathal/Seegraben pumping stations.