Artificial Recharge of Humic Ground Water

The purpose of this study was to investigate the efficiency of soil in removing natural organic matter from humic ground waters using artificial recharge. The study site, in western Denmark, was a 10 000 m2 football field of which 2000 m2 served as an infiltration field. The impact of the artificial recharge was studied by monitoring the water level and the quality of the underlying shallow aquifer. The humic ground water contained mainly humic acids with an organic carbon (OC) concentration of 100 to 200 mg C L−1. A total of 5000 m3 of humic ground water were sprinkled onto the infiltration field at an average rate of 4.25 mm h−1. This resulted in a rise in the water table of the shallow aquifer. The organic matter concentration of the water in the shallow aquifer, however, remained below 2.7 mg C L−1. The organic matter concentration of the pore water in the unsaturated zone was measured at the end of the experiment. The organic matter concentration of the pore water decreased from 105 mg C L−1 at 0.5 m to 20 mg C L−1 at 2.5 m under the infiltration field indicating that the soil removed the organic matter from the humic ground water. From these results we conclude that artificial recharge is a possible method for humic ground water treatment.