Determination of Zn partition coefficient and simulation of reactive transport from landfills in Mar Del Plata, Argentina

The distribution coefficient (Kd) expresses the relationship between the concentration of an element, which is adsorbed in the solid surface and its remaining concentration in the solution. The Kd is a very important factor in reactive transport, representing the source/sink term, and explaining the difference between the velocity of transport of non-conservative elements (Kd>0) and water flow velocity. In this paper, the Kd value for Zn element in loess like sediments forming the Pampeano aquifer is determined and this value is used in the modeling of reactive transport from the landfill of the city of Mar del Plata (Argentina). The determination of Kd value was done by means of batch experiments. The results obtained showed good agreement with Freundlich isotherm, with a value of K_F=300.95 ml g⁻¹ and a super index value b of 0.3961. These values were applied to reactive transport modeling using Visual Modflow code. The Zn plume obtained showed the low mobility of the element in the oxidizing conditions of the environment.