Over the past 10 years, sewage treatment plants throughout Switzerland have implemented numerous energy-efficiency measures and thus cut their external electricity supply costs by an estimated 80 million kWh per annum. According to studies carried out by the Swiss Federal Office of Energy, approximately 50 million kWh p.a. originate from their own supplementary electricity production. The estimated savings effect of efficiency measures is around 30 million kWh p.a.
The optimisation of a sewage treatment plant begins with an energy analysis. Approximately 200 sewage treatment plants in Switzerland have undergone an energy analysis within the scope of the "SwissEnergy for infrastructure plants" programme, and have subsequently implemented a variety of efficiency measures. An evaluation of more than 100 in-depth analyses resulted in the following findings: