Flow patterns of dairy wastewater constructed wetlands in a cold climate

Pete Muñoz*, Aleksandra Drizo, W. Cully Hession

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

72 Citations (Scopus)


Conservative tracer experiments, and spatial temperature and dissolved oxygen mapping within four subsurface treatment wetlands employed in this study demonstrated the importance of supplemental aeration and vegetation in reducing preferential flows in cold climate treatment wetlands. Four constructed wetlands, employing horizontal subsurface flow were used to treat dairy wastewater in a 2×2 factorial design consisting of two wetland cells with vegetation and two with supplemental aeration. Four tracer studies were conducted between November 2004 and May 2005. Two key observations were made, demonstrating that vegetation and aeration can be utilized in cold regions to prevent clogging and freezing, thereby reducing preferential flow paths which can reduce treatment efficiencies: (1) vegetation contributed to thermal protection and (2) aeration increased temperature and mixing. A comparison of multiple wetland cells with varying flow rates showed that the use of pore volume in tracer response curves was a better indicator of preferential flows than other indicators including volumetric efficiency, hydraulic efficiency and number of continuosly stirred tank reactors (CSTRs). This research helps further establish how constructed wetlands are a viable tool for treating wastewater in cold climates.

Original languageEnglish
Pages (from-to)3209-3218
Number of pages10
JournalWater Research
Issue number17
Publication statusPublished - Oct 2006


  • Aeration
  • Constructed wetlands
  • Hydraulic efficiency
  • Tracer study

ASJC Scopus subject areas

  • Earth-Surface Processes


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