Wastewater inlet station energy cost reduced by €42k per year

Two screw pumps operated at less than a third of their nominal power. SAM4 Energy determined that a single screw pump could easily handle all the flow during dry weather, saving €42k/year and reducing carbon footprint by 75 tons/year.

Two Archimedes screw pumps operated in parallel at the inlet station to a wastewater treatment plant. Both pumps were rated to operate at a nominal power of 185 kW. Based on operational data, SAM4 Energy determined that the pumps spent almost half of their time running at less than a third of nominal power, reducing the station’s energy efficiency by 25%.

Because the region served by the treatment plant uses combined sewers, where rainfall flows through the same piping as domestic waste, the inlet station was designed to handle weather-related surges in flow. Our Energy team used historical data to determine that a single screw pump could easily handle all the flow during dry weather. which is nine months of the year in this region. This single pump would then operate at a higher load, improving its efficiency.

This simple operational change would save the pump owner €42,000 per year in energy costs and reduce the station’s carbon footprint by 75 metric tons per year.