Processes of Iron and Manganese Retention in Laboratory Peat Microcosms Subjected to Acid Mine Drainage

摘要: Despite increasing use of constructed wetlands for treatment metal-enriched acid coal mine drainage (AMD), the biotic and abiotic mechanisms metal retention in such are poorly understood. The present study was conducted to evaluate processes responsible Fe Mn peat effects microbial activity, pH, temperature, concentration AMD on these processes. Experimental units consisted 30 g (wet wt.) fresh Sphagnum peat, which repeatedly flushed with synthetic at pH 3.5. Of four major cation (cation exchange, complexation organics, precipitation as oxides, sulfides), oxidation binding organics were predominant, oxides organically bound making up, respectively, 62 22% total end experiment. Whereas a finite process, reaching saturation 12 mg g⁻¹ dry Fe-oxide increased steadily throughout At 3.5, depressed by addition an antiseptic (formaldehyde) AMD, suggesting that process microbially mediated. Iron oxide higher 5.5 than 3.5 less presence formaldehyde AMD. efficiency remove from diminished low temperature ( 100 L⁻¹). Manganese small compared Fe, retained almost exclusively exchangeable Mn²⁺. Retention Fe²⁺ not affected Mn²⁺ had accumulated subjected readily resolubilized any three investigated: photoreduction, Fe(III) reduction under reducing conditions, exposure simulated precipitation. These findings suggest may be appropriate technology soluble concentration, but inadequate treating waters rich Mn. This work supported ant USEPA R-812379-01-0.