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This article in JEQ

  1. Vol. 28 No. 5, p. 1665-1673
    Received: Oct 27, 1998

    * Corresponding author(s): machate@gsf.de
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Purification of Fuel and Nitrate Contaminated Ground Water Using a Free Water Surface Constructed Wetland Plant

  1. Thomas Machate *,
  2. Elisabeth Heuermann,
  3. Karl-Werner Schramm and
  4. Antonius Kettrup
  1. Umweltschutz Süd GmbH & Co., Angererstr. 38, D-89796 München, Germany;
    Umweltschutz Nord GmbH & Co., Industriepark 6, D-27777 Ganderkesee, Germany;
    GSF-Research Center of Environment and Health, Institute of Ecological Chemistry, Ingolstädter Landstr. 1, D-85758 Neuherberg, D-Germany.



Contaminated ground water from a former coke plant site was purified in a free water surface (FWS) constructed wetland plant during a 3-mo short-term experiment. The pilot plant (total surface area 27 m2) was filled with a 1 m thick lava-gravel substrate planted with cattail (Typha spp.) and bulrush (Scirpus lacustris). Major contaminants were low to moderate concentrations of polycyclic aromatic hydrocarbons (PAH 50–9000 µg L−1 according to USEPA, 1-methylnaphthalene 2–1900 µg L−1, 2-methylnaphthalene 3–4300 µg L−1), BTEX (10–450 µg L−1), nitrate (60 mg L−1 as N), and nitrite (7 mg L−1 as N). The wetland was dosed at hydraulic loading rates of qA = 4.8 and 9.6 cm d−1 with a hydraulic residence time (HRT) of 13.7 and 6.8 d. The surface removal rates of PAH were between 98.8 and 1914 mg m−2 d−1. Efficiency was always >99%. Extraction of lava gravel showed that approx. 0.4% of the applied PAH were retained on the substratum. The ratio of ∑2,3-ring PAH and ∑4,5,6-ring PAH showed a shift from 1:0.11 in water (influent) to 1:2.5 in lava (Tank 1). The removal of BTEX was >99%, but might be in part due to volatilization. The efficiency in the removal of nitrate was 91% (2.47–3.34 g m−2 d−1) and of nitrite was 97% (0.034–0.036 g m−2 d−1). Purification performance was not influenced by hydraulic loading rates or after die-back of the macrophytes.

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