Bailín HCH landfill is located in the small Pyrenees town of Sabiñánigo, Huesca, in the north of Spain.
The site is a former unlined landfill located in the Bailín creek, over a complex fractured geological media.
The main receptor in the area is the Gállego River, which is located 1 km away in West direction.
The existing facilities, in the Bailin landfill area, include a physico-chemical treatment plant to deal with
the pollutant pumped from the landfill. The water treatment process removes over 99% of organochlorinated
pesticides as well as volatile and semi volatile organic compounds from the water polluted by HCH
and other compounds.
Important topographic gradients control runoffs and infiltration rates, groundwater flows
towards Bailín creek and Gállego River within a shallow fracture network in the first meters.
In depth, the Bailín aquifer, an alternation of vertical mudstone and sandstone layers with
different fracture distributions, controls the preferential groundwater pathways.
The special geographic and geological frame where the landfill is located, as well as
the nature of the pollutant, has generated a plume that has spread across the fractures
and moves controlled by the geological settings. Although the principal contaminated area
is close to the source zone, sandstone layers constitute the main pathways that contribute
to spread the plume. There is only one sandstone layer that has enough longitudinal continuity
to reach the river. This layer is called M Layer, which is 4 m width, and connects the landfill with
the river 800 meters down gradient. In this M layer is where the ISCO pilot test is proposed to be carried out.
Under major security measures the Bailin HCH landfill has been dismantled. A new security cell hosts the different type of pollutants that have been found. It has been estimated a total volume of 177.000 m3 of residues that may be classified as follows: