TRITHON facility is a centrifugal and membrane hydrodynamic separator designed to treat a part of the particulate phase of the stormwater runoff. For sediment in the particle size fractions ≥ 50 µm, the removal efficiencies were from 54% up to 91%.For size fractions ≥ 100 µm, the removal efficiencies were from 75% up to 99%. His capacity to treat an accidental spill of 20 kg of floating materials with a density <0.93 has been tested and the mean removal efficiency for polyethylene beads was 99,9%.