Wrompa constitutes the first heat pump in Poland installed on a raw sewage stream, with a nominal capacity of 12.5 MW. The technology facilitates efficient recovery of waste heat, thereby contributing to reductions in CO2 emissions and achieving measurable energy savings, while covering up to 5% of the heat demand of Wrocław residents supplied via the district heating network. The decrease in influent sewage temperature to the treatment plant, by up to approximately 1.5 °C, which could potentially slow down biological processes within the wastewater treatment facility, is mitigated through compensatory measures designed to maintain process stability. This article presents the principle of operation, the resulting energy benefits, and the overall impact of the system on wastewater treatment plant performance.