ABSTRACT
Artificial recharge is increasingly used in Finland to produce drinking waters from surface waters, which often have high organic carbon content. In this research we studied the changes in organic carbon (NPOC, AOC), microbial numbers and microbial growth during artificial recharge of ground water. Slow sand filtration decreased the content of NPOC only slightly, the content of AOC decreased on average by 74 µg AOC/l. Chlorination of artificially recharged ground waters increased the concentration of assimilable organic carbon on average by 56 µg AOC/l. Chlorination decreased the number of microbes in filtrated waters. However, chlorination halted microbial growth only temporarily. Surprisingly, microbial growth was enhanced in chlorinated samples compared to unchlorinated drinking waters.
