Erasmusgracht Amsterdam: horizontal helophyte filter for purifying wastewater and rainwater © atelier GROENBLAUW, Madeleine d’Ersu

Horizontal helophyte filter


  • Depth: 80 cm
  • Vegetation form: helophytes and other water plants


Besides the system described above, filters also exist through which the wastewater passes horizontally. These filters do not require drainpipes or pumps and are therefore simpler in their construction. As such, this type of filter requires less maintenance than vertical filters. Its uses include treating polluted runoff from roads and car parks.

© atelier GROENBLAUW