LIFE SURFING: PILOT TEST TO REMOVE THE CONTAMINATION SOURCE

Pumpable dense residues are considered exhausted in Bailin landfill. The removal of the dense phase adhered to the walls of the rock fractures is the objective of a set of techniques to be tested on field

Pumpable dense residues are considered exhausted in Bailin landfill. Currently, a dense residue adhered to the walls of the fractures (non-pumpable or residual) is remaining. This causes groundwater contamination once they come into contact. Hence, destroying these dense adhered residues entails the elimination of the contamination source. This is the objective of the LIFE SURFING project, that will combine the use of in situ chemical oxidation techniques with the action of surfactantes.

An estimate of 3 to 4 m3 of non-pumpable dense residues is remaining in Bailin. They can be found in the fractures of a vertical layer of sandstone of 4 to 6 m width, reaching up to 40 m depth. The total affected lenght has around 500m. This is the only layer that has continuity with the river Gallego.

LIFE SURFING: PILOT TEST TO REMOVE THE CONTAMINATION SOURCE -

The LIFE SURFING project is coordinated by the Government of Aragon, having a total budget of 2.1 million euros. The European Union finances the 57% of the project, and the Government of Aragon contributes with 570,836 euros.

The project has a 4-year duration, from 2019 to 2020. The partners involved in the project are the Department of Agriculture, Livestock and Environment of the Government of Aragon, the Aragonese Society of Agri-environmental Management (SARGA), the Internacional HCH & Pesticides Association (IHPA), INPROQUIMA group from the Complutense University of Madrid, and the University of Stuttgart.

The objective is the total cleaning of 60m of the vertical layer of sandstone.

To achieve that, 6 boreholes will be drilled in the sandstone, with a 10m distance, in the location of the old Bailin landfill.

The first phase will consist in the extraction of dense phase enhanced by surfactants. After the decanting and obtention of dense phase, these contaminated water will be pre-treated with three paralell systems. The first one is the oxidation with persulfate, using an alkaline activation. The second is the hidro-oxidation and subsequent retention of volatile compounds generated in the activated carbon. And the third one is the retention in activated carbon and subsequent partial recovery of this carbon by oxidizing it with persulfate and thermal activation. The resulting water will be conducted to the storm pools for its treatment.

These treatments will be done on site, at the old Bailin landfill.

In a second phase, a series of injections will be done in the boreholes, to perform an oxidation enhanced by surfactants. Weeks can pass between injections, depending on the assessment of the rebound effect.

In a third phase, a series of injections for the oxidation of dissolved contaminants will be done. Weeks can pass between injections, depending on the assessment of the rebound effect.

The test aims to prove the effeiciency of each one of these methods.

At the same time, the University of Stuttgart will perform replicability tests and a transferability test in a cells of 10 m3 , in a granular aquifer and for other dense contaminants, such as creosotes and PCBs.