Implications of sulfate-reduction and pyrite-formation processes for water quality in a constructed wetland: preliminary observation.
Hedin-RS; Hyman-DM; Hammack-RW
Mine Drainage and Surface Mine Reclamation. Volume I: Mine Water and Mine Waste. Vol. I. Pittsburgh, PA: U.S. Bureau of Mines, 1988 Apr; :382-388
Preliminary observations of water chemistry in a recently constructed Typha wetland indicate significant improvements in water quality in areas where reduction processes are occurring. Where the organic substrate was black and loose, sulfate concentrations were 16-59 pct less than inflow, iron concentrations were 52-98 pct lower, and pH was 2-3 units higher. Ninety-six pct of the iron in these areas was in the reduced, ferrous form. Where the organic substrate was blanketed with orange iron oxyhydroxides, water chemistry was similar to inflow, and dissolved iron was predominantly in the oxidized, ferric form. Analyses of the organic substrate (mushroom compost) showed an enrichment of elemental sulfur in all samples. One substrate sample, collected 15 cm beneath the surface, contained both elemental sulfur and pyrite. Removal of iron from acid mine drainage (AMD) through pyrite formation and storage in anoxic sediments may be preferable to removal by oxidation and hydrolysis because of pyrite's density, negligible solubility in acid water, and placement in the substrate. Researchers should consider designs that would emphasize movement of AMD through organic-rich, anoxic substrates and thus maximize sulfate reduction and pyrite-forming processes.
Sulfates; Water-analysis; Quality-control; Iron-compounds; Oxidation; Organic-sulfates; Organic-compounds; Sampling; Acids; Waste-treatment
IH; Conference/Symposia Proceedings
Mine Drainage and Surface Mine Reclamation. Volume I: Mine Water and Mine Waste