Présentations Colloques

The soil is the medium through which infiltration occurs, and its capacity to attenuate pollutants and allowing infiltration is critical for designing and setting up Managed Aquifer Recharge (MAR) and large scale phyto-treatment schemes. Within this work, the buffering capacity (on nutrients, pharmaceutical compounds and Terbuthylazine) of two soils and its evolution under the continuous infiltration of Treated WasteWater is evaluated. The soils have been sampled at two different experimental field sites- Sant'Alessio Induced RiverBank Filtration (IRBF) plant and San Niccolò large scale phyto-treatment test-plant. Chemical analysis for pH, CEC, organic and inorganic carbon were run for both soil types, like also physical analysis for grain size and particle surface area. High differences between the two soil were detected, in particularly related to the organic carbon contents (48% and 0,9 % for the soil from the phyto-tretment test-plant and for the soil from the IRBF plant respectively). Sorption tests have been performed (in abiotic conditions) in order to evaluate the buffer effect related only to the adsorption capacity of the soils.**Three columns (50*9 cm, specifically designed to minimize the pharmaceutical adsorption on the column components) per each soil were set up. There, water was continuously infiltrated bottom-to-top with a constant flow of 540 mL d (from 2 to 5 total pore volume exchanged per week, respectively for the San Niccolò and Sant'Alessio soil). The TWW used for the experiment came from a local wastewater treatment plant, weekly collected and used as infiltration source with the addition of some selected chemical compounds (pharmaceuticals and pesticides). Water quality was investigated by means of periodic water sampling from each column (4 points distributed along the column) and from the TWW collection point. The experiments presented here allowed getting further insights on soil capacity, related to its physico-chemical characteristics, to buffer peri-urban water related potentially negative effect on the beneficial result provided by MAR and large scale phyto-treatment plant.