388144 - APPLICATION OF IRON FILINGS TO REDUCE INTERNAL PHOSPHORUS LOADING IN LAKES
Monday, June 4
10:30 AM - 12:00 PM
Location: Lakeshore B
John Gulliver, Minneapolis – University of Minnesota; William Arnold, Minneapolis – University of Minnesota
Phosphorus (P) recycling from lake sediments to overlying water, also termed internal loading, can be significant in causing eutrophication and water quality degradation of lakes. Internal phosphorus loading must be addressed to improve lake water quality, support lake recovery and restoration efforts, and achieve watershed total maximum daily load (TMDL) goals. In this study, the addition of zero-valent iron filings to lake sediments was investigated as a measure to control sediment-P release. Using sediment-water columns collected from two eutrophic Minnesota lakes, experimental additions of iron filings were carried out to determine the iron dose-P release responses under controlled oxic and anoxic conditions. A dose greater than 0.05 g iron/cm2 provided 75 to 96% reduction in P concentrations in the pore water and water column and thus decreased the P flux across the sediment-water interface, even under anoxic conditions. Factors affecting the effectiveness of iron dosing, and the impact of iron addition on the mobility of sediment-P pools were also examined. The findings of this study demonstrate the potential for iron filings application as a lake treatment technology with substantial benefits to lake water quality and trophic status.