Rootzone dynamics in constructed wetlands receiving wastewater: a comparison of vertical and horizontal flow systems

Peter F. Breen, Alan J. Chick

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45 Citations (Scopus)


Profile conditions were examined in both small experimental and pilot scale sub-surface flow wetlands. The study systems differed in their hydraulic design. The experimental systems had a vertical up-flow design whereas the pilot system was a horizontal flow trench design. Both systems were found to have significant physical, chemical and biological gradients within the sub-surface profile. System age and plant root density appear to be important factors in determining profile differentiation within the experimental systems. Root densities were found to be partitioned between the upper and lower layers on a 70%/30% split, respectively. However, in the experimental systems as the systems aged and root densities increased beyond 112–251 g.m−2 chemical water quality differentiation in the profile disappeared. Pilot scale systems were found to have physical gradients within the profile as evidenced by hydraulic short-circuiting. Vertical root density distribution is proposed as a major cause of this condition in horizontal flow systems.

Original languageEnglish
Pages (from-to)281-290
Number of pages10
JournalWater Science and Technology
Issue number3
Publication statusPublished - 1 Jan 1995
Externally publishedYes


  • aquatic macrophyte
  • Eleocharis sphacelata
  • nutrient removal
  • rootzone
  • Schoenoplectus validus
  • wastewater treatment
  • wetland hydraulics
  • Wetlands (artificial or constructed)

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