Groundwater
Porous Media Flow Model
The Porous Media Flow Model, also known as Artificial Aquifer (or physical sandbox model), is used to conduct laboratory large-scale infiltration and tracer tests to determine the soil infiltration rate and natural (or incremented) contaminants retention and/or degradation capacity. This facility can be used to simulate different situations, such as:
- Soil-Aquifer Treatment (SAT) in a Managed Aquifer Recharge (MAR) basin
- Risk of contaminants leaching from a spill
- Reactive barriers for groundwater rehabilitation
- Contaminants release from a contaminated porous material
The facility is approx. 3.5 m long, 1 m wide, and 2 m high, and can be filled with the porous medium (soil) to be studied. It can be divided up to three different compartments to perform simultaneous experiments. Both saturated and non-saturated conditions can be simulated.
The facility is equipped with three piezometers, Teflon cups, and monitoring devices such as multiparametric probes (level, pH, temperature, electrical conductivity, and redox) to assess flow and transport.
A complementary soil-column experiments apparatus is equipped to study the risk of pollutant leaching through soils and other materials using (1) batch experiments to assess the maximum concentrations of release in equilibrium conditions and (2) soil-columns facilities to quantify the movement of water and contaminants in dynamic conditions. Several other complementary tests can be performed to soil samples, like: humidity, density, porosity, and granulometry.
Porous Media Contaminant Transport Model
Three sand tanks were built for the purpose of studying water quality changes of both infiltrating treated wastewater and groundwater during different soil aquifer treatment (SAT) scenarios, one of the techniques of managed aquifer recharge. The tanks were designed to assess hydrogeochemical processes in both the vadose zone (during infiltration) and saturated zone (groundwater) under controlled conditions and via long-term experiments.
The tank facility consists of three individual L-shaped tank structures, made from HDPE (high density polypropylene), fitted between concrete walls. The vertical part of the L-shaped tank is 2.5 m high, and acts as the unsaturated infiltration zone, while the horizontal part, with a length of approx. 2.8 m, features a saturated zone in the lower part (continuous flowing groundwater) and an unsaturated zone above. The height of the saturated zone can be adapted by regulating the constant head at the outflow.
The porous media of the tanks can be adapted to the desired study design and research purpose. The unique feature of the tanks is the continuous inflow of groundwater, hence simulating a continuous flowing groundwater in an aquifer.
It allows sampling in the vadose zone and in both the saturated and unsaturated zones for hydrochemical analysis.
