Constructed wetlands have the potential to trap and remove metals in mine wastewater. To determine the effectiveness of constructed wetlands for treating selected heavy metals in neutral mine effluent typical of lead mines, eight laboratory-scale constructed wetlands were set up to
treat a synthetic, slightly alkaline, mine water containing 34.2 mg/L sulfate (SO42−), 50 μg/L lead (Pb), and 300 μg/L zinc (Zn). After 45 days, one of the wetlands was switched to treat a synthetic smelter effluent with a much greater load of SO42−,
sodium (Na+), and Pb. Temperature, hydraulic loading, and substrate composition typically did not affect treatment efficiency. The pH of the effluent was reduced from 8.0 to 8.5 to near neutral. The average removal in the eight wetlands was 90% for Pb and 72% for Zn. In wetlands
operating on synthetic mine water, SO42− was completely removed, likely by conversion to sulfide by sulfate-reducing bacteria. In the wetland operating on synthetic smelter effluent, only approximately 25% of 6 g/L influent sulfate was removed, and a breakthrough
period of 4 days for Na+ was observed. Whole effluent toxicity assays on undiluted wetland effluent from wetlands treating mine and smelter water had 100% survival of fathead minnows and Daphnia magnia. Survival of Ceriodaphnia dubia was zero in undiluted effluent,
but 75 to 100% survival was observed when the effluent was diluted to one-half strength.
Water Environment Research® (WER®) publishes peer-reviewed research papers, research notes, state-of-the-art and critical reviews on original, fundamental and applied research in all scientific and technical areas related to water quality, pollution control, and management. An annual Literature Review provides a review of published books and articles on water quality topics from the previous year. Published as: Sewage Works Journal, 1928 - 1949; Sewage and Industrial Wastes, 1950 - 1959; Journal Water Pollution Control Federation, 1959 - Oct 1989; Research Journal Water Pollution Control Federation, Nov 1989 - 1991; Water Environment Research, 1992 - present.