LITOCLEAN was able to meet on time the objectives set in a decontamination project of a chemical plant affected by various types of contaminants. The groundwater of this plant was contaminated but there were also affected soils, which had to be remediated, as a secondary focus, so that they would not cause a new contamination of the water once processed. There were more than 3,000m2 of affected soils up to 5 meters deep and their associated waters, in three affected areas within the same site sharing three different types of contaminants (organochlorines, hydrocarbons and arsenic), in addition to the presence of sulfides, which also had to be remediated. But as if the complexity of the case were not enough, LITOCLEAN had to carry out the work with the constraints of time and space against it. The land concession was changing hands, so demolition work was being carried out at the same time and, therefore, the time to achieve the proposed objectives was very limited, as was the space in which to operate.
The Quantitative Risk Analysis showed that the groundwater affected by organochlorine compounds, as well as the adjacent soils, were the ones with a potential risk to human health that exceeded the threshold of acceptability. Once all the conditioning factors had been analyzed and the Risk Analysis had been carried out, it was decided to excavate the contaminated soil selectively, that is, separating and treating only the contaminated soil. At the same time, the groundwater was pumped, treated and re-infiltrated. As the soils to be treated were generated, on-site remediation was carried out and, once the objectives were achieved, the decontaminated soil was replaced.
The complexity of the project involved the application of different remediation techniques: aeration for excavated soils, chemical oxidation with activated sodium persulfate for groundwater and remnant soils, and oxidation with hydrogen peroxide in sulfide-affected soils. Both oxidation treatments were previously tested by pilot tests to optimize and ensure their performance. With the combination of these techniques, the objectives were met within the time frame and no waste was generated.
In less than a year the project’s objectives had been met, which is a great success for LITOCLEAN, as project manager Joan Varias explains: “Similar projects take three years to complete, but this one was completed in just 11 months. That’s a record”. In addition, “it was a particularly complex project because of the different types of contaminants and the fact that we had to work in parallel with the demolition of buildings and facilities on the same site,” says Varias.
Once again, the extensive knowledge and long experience of LITOCLEAN and all its professionals allowed that finally about 20,000 m3of soil were treated and replaced as well as 23,000 m3 of water pumped and treated, which meant the achievement of the objectives set.
The TEMA LITOCLEAN Group has a long history working in soil investigation and decontamination projects and as an environmental and safety consultant.
