Degradation of emerging contaminants in reclaimed water through soil aquifer treatment (SAT)

Soil aquifer treatment (SAT) is considered to be an alternative technique able to enhance recharged water quality for aquifer recharge purposes. It allows the reuse of treated wastewater, which usually contains some recalcitrant organic micropollutants such as pharmaceutical and personal care products (PPCPs) and endocrine disrupting chemicals (EDCs). This study reports the removal capacity for a selection of organic micropollutants during SAT and the characterisation of the recharge system for the interpretation of the data. The experiment was performed in Angerville (France), where the treated wastewater effluent of the wastewater treatment plant (WWTP) is directly infiltrated through an excavated infiltration pond after biological treatment. The system was instrumented by installing piezometers downgradient of the infiltration pond, which were monitored, together with other reference points, and analysed for detailed interpretation. Results on the site characterisation allowed the quantification of the mixing proportion of the recharge water and groundwater and identification of the redox conditions encountered within the aquifer. With respect to the targeted micropollutants, results showed that they exhibited different behaviour during infiltration. Examples of atrazine, gemfibrozil and carbamazepine are discussed as a representation of the most characteristic patterns of organic contaminant fate after recharge.