The 'chapapote' of Arganda begins to disappear: they remove 66,000 tons of waste

The Community of Madrid has removed more than 66,000 tons of waste from the artificial lagoons of Arganda del Rey. The municipality has been surrounded by two residual oil pools for decades. Since 2014, the regional Executive has led the largest European project for the recovery of a natural environment. The key to the initiative lies in the second life of the spills: the extracted material – mostly tar – is later reused in other industries. The region's Environment Minister, Carlos Novillo, visited the place this Thursday: “The regional Executive has a great commitment to the circular economy to obtain new resources, as is being done with this initiative,” he said..

The origin of the disaster dates back decades.. A company dedicated to the regeneration of used oils was located in the current Southeast Regional Park. At that time, there was no legislation dedicated to the protection of the environment.. Later, the entity went bankrupt in the 90s and entered bankruptcy. “What we wanted is for those responsible to pay for the restoration,” says María Ángeles Nieto, from Ecologistas en Acción. It was not so. Instead, the public administration acquired the land in 2009 to take charge of the recovery of the area themselves.

Since then, Arganda del Rey has coexisted with two large tar ponds. The largest exceeded 12,500 square meters and came to accumulate 50,000 cubic meters of tar. The second had about 2,000 m2 and about 10,000 meters in volume. “We would have liked it not to have been necessary to invest public money,” continues Nieto. The recovery process is slow, but things in the palace are slow. The idea of reusing the extracted tar involves a tricky conversion process. The waste is turned into fuel for cement factories.

Renovation of six hectares

The second phase of a project led by the regional government to repair contaminated soil will begin in August. This stage will focus on the selective excavation and environmental recovery of the affected areas, with a budget of 22.8 million euros and a duration until November 2026.. In the first stage of the project, the extraction and energy recovery of the contaminated materials was carried out. This phase implied the use of suction pumps and mechanical methods to extract the materials from the lagoons.. However, an additional challenge was encountered when a denser and more viscous residue, extremely acidic, was discovered located below the water table of the aquifer, which required special measures to avoid groundwater contamination..

To facilitate the safe handling of the extracted materials, it was necessary to build an impermeable cement screen and other infrastructures for the collection and transport to the management plant.. At the plant, the contaminated materials were prepared and transformed into a solid fuel for future use —404 million kilowatts/hour have been obtained, equivalent to the amount of thermal and electrical energy consumed by 116,000 Spanish homes in one year—. The final phase of the project, which is scheduled for December 2026 through the end of 2027, will focus on the ecological restoration of more than six hectares of land previously affected by contamination.. The objective is to recover the biodiversity and health of the intervened area.