BEHANDLING AV ETT JÄRNRIKT GRUNDVATTEN MED NITRAT / The Treatment of Iron-rich Groundwater with Nitrate
Recent biogeochemical studies suggest that denitrification in groundwater is widespread, and that there is a close coupling between denitrification and the cycling of groundwater iron. The possibility to use this coupling for in situ treatment of iron-rich groundwater has been studied in a full-scale field test at Knislinge Waterworks, Ö. Göinge Community. Under a 50 day’s period, 500 kg of sodium nitrate has been injected into a confined aquifer containing oxygen-free groundwater with 3 to 5 mg/1 of ferrous iron and 4 to 5 mg/1 of dissolved organic carbon. Consequent changes in groundwater chemistry have been followed under 135 days in 3 groups of observation wells situated in the distance of 10, 30 and 60 m from the injection well. One to 3 weeks after the breakthrough of the nitrate front, the concentrations of ferrous iron dropped in all observation wells with 80 to 90 %. The rise of the iron concentrations after the termination of the nitrate pulse was only slow. “Complete abstract not presented.”