The concept of the new water treatment system was developed. A primary area was defined in which such technology is intended to be used: water treatment in compact flue-gas condensation systems for a low-power wood-fuelled biomass boiler. A prototype operating based on invented technology was built. An experimental plan was developed, and an experimental stand was constructed to determine the prototype’s efficiency. Based on the study’s results, it was concluded that the prototype could operate effectively in the laboratory environment: achievable efficiency is equal on average between 57.84 % and 88.09 % depending on the operating mode. The result is assessed as positive. TRL 3 has been reached.