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. A bench scale evaluation of organic substrates for use in constructed wetlands for the treatment of acid mine drainage. Acid mine drainage; Heavy metals; Constructed wetlands; Wetlands. SUBSTRATE HYDRAULIC CONDUCTIVITY. Figure 12. Substrate saturated hydraulic conductivity values through time during study. OBSERVATIONS The following summary of visual observations will address primarily the timing and nature of precipitates which were formed and the development of FeS "black spots". Effluent visual characteristics will also be discussed. Following the introduction of AMD into th
. A bench scale evaluation of organic substrates for use in constructed wetlands for the treatment of acid mine drainage. Acid mine drainage; Heavy metals; Constructed wetlands; Wetlands. SUBSTRATE HYDRAULIC CONDUCTIVITY. Figure 12. Substrate saturated hydraulic conductivity values through time during study. OBSERVATIONS The following summary of visual observations will address primarily the timing and nature of precipitates which were formed and the development of FeS "black spots". Effluent visual characteristics will also be discussed. Following the introduction of AMD into the columns, effluent waters were typically murky and filled with suspended colloids of what appeared to Fe hydroxyoxides. It is likely that Al hydroxyoxides and gypsum were also present. Effluent water from the mushroom composts did not exhibit the milky orange/yellow to cream color of the other effluents but rather was organic-rich, foul-smelling and deep tea-brown in color. Precipitates first began to form in the gravels at the base of the columns after approximately 11 days in all columns with the exception of column 1 (Eko- Compost). Through time, these precipitates spread throughout the gravel and into the bottom few centimeters of substrate. Some of these precipitates were originally a light yellow to orange in color but became darker orange with time and were presumed to be Fe and possibly Al hydroxyoxides. Fouling was initially strongest in both mushroom composts, most likely due to their high alkalinity, and very slight in Eko-Compost and Farmers peat. By day 46 of the study, effluent water from the mushroom composts had more or less 40. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Schafer and Associates; Schafer and Associates; Montana. Abandoned Mine Reclamation Bureau. Bozeman, Mont. : The Asso
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