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Germany, Austria, Switzerland


Granular Activated Carbon Filtration

Designed as a continuously operating filtration with horizontal water flow it eliminates micropollutants in waste water.

Unique Features

For the same effective filtration surface, the overall footprint of a horizontal flow filter is designed significantly:

  • Smaller footprint
  • Less construction size
  • Simplified construction form
  • Additional filtration capacity can be created by reconstruction of existing filter tanks
  • Exactly defined thickness of the filtration media layer
  • Less compressed air needed for the back wash process
  • Flexible arrangement


Aiming to minimize the GAC-filtre footprint, we have evolved a particularly efficient and patented solution, based on horizontal filtration. In the Passavant® Granular Activated Carbon Filtration (GAC), the feed water enters the GAC-bed through an inner distribution cylinder. While micropollutants are being adsorbed in the GAC, the treated effluent flows horizontally-radially towards the shell.  Between the GAC-bed and the vessel wall are located slit sieves with fine slots. The design of the the slit sieves (manifold and shell) is based on decades of experience with our JohnsonScreens slot sieves / vee-wire. The system comes along with a backwash system to control biological growth.