| Popis: |
The vertical flow pond at Jennings Environmental Education Center, Butler County, PA, was constructed in 1997. After five years of operation, the system continued to produce alkalinity and remove iron and aluminum, but the flow rate through the system has continuous declined. To determine the type and pattern of chemical distribution throughout the system, 9 cores were obtained and analyzed for iron, manganese, aluminum, silica, sulfate, calcium and trace metal concentrations. Iron precipitates accumulated in the upper 7-10 cm of the spent mushroom compost and limestone mixture with the majority of aluminum precipitate accumulation occurring between 10 and 20 cm below the surface of the media. Although there was sufficient CaCO3 in the substrate to continue to provide alkaline addition, the accumulation of metals in the upper 10 cm of the substrate has reduced the permeability of the substrate. |
