Source water quality requirements for artificial groundwater recharge

Abstract

This study was an investigation of the need for pre-treatment of a new raw water source for artificial groundwater recharge. The study was done through a column test, well sampling and survey data relating to 11 artificial recharge plants in Sweden. The column test showed that only 30% of the natural organic matter (NOM) was removed from the new raw water source during infiltration. The survey revealed that the new water source's quality was within the range requiring pre-treatment prior to infiltration. The well sampling results showed a significant correlation between the NOM content in the raw and treated waters for WTPs without pre-treatment (r = 0.78 and ρ = 0.04), indicating one of the short-term limitations of artificial recharge. The study results indicate that the new raw water source is unsuitable for direct use in artificial recharge and that treatment is required prior to infiltration. HIGHLIGHTS This study shows the synergetic effect of chemical flocculation and managed aquifer recharge (MAR).; NOM removal limitations during artificial recharge were observed.; The investigation showed indications of different treatment efficiencies during MAR depending on NOM composition.; Treatment efficiencies from Swedish water utilities are made available to an international readership.;

Keywords

• chemical flocculation
• managed aquifer recharge (mar)
• natural organic matter (nom)