Long-term effects of alum sludge application to land

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Virginia Tech


Previous research relating to alum sludge land application has primarily been restricted to laboratory studies of short-term environmental effects. In general, most research has concluded that the environmental effects of alum sludge constituents can be easily controlled.

This study investigated the fate of land-applied alum sludge constituents nearly three years after incorporation into a Slagle soil. An existing field site was used. The site had been used for a pilot study examining the land application of alum sludge from the Harwood's Mill Water Treatment Plant in Newport News, Virginia. Alum sludge and lime were applied to the site in November, 1989. Soil, soilwater, groundwater and pine needle tissue media were sampled during the summer of 1992. It was determined that the alum sludge posed no observable long-term threat to groundwater quality or vegetative productivity.

Migration of alum sludge constituents through the soil profile could not be confirmed in this research. However, acid precipitation may have destroyed the alkalinity added to the soil. Thus, long-term management of alum sludge land application to acid soils may require additional increments of alkalinity.