The steps of a land decontamination project

Do you need to have a space decontaminated? If so, you may have some questions regarding this project, which is carried out following a rigorous procedure.

In order to better understand the different steps involved in a decontamination project, here they are in detail.

The decontamination project - step by step

Phase 1- the environmental assessment of the site

The first step of a decontamination project is to identify the potential risks of the contaminated land. To do this, experts will visit the site while also consulting aerial photographs as well as geological and hydrogeological maps. In order to gather even more information about the site in question, a request for further context needs to be made to the authorities concerned.

This measure aims to know the background of the land and therefore, the nature of the businesses or buildings (factory, garage or other) which have been placed on it in previous years.

In the same regard, accessing a title consultation at the Registry Office can offer a complimentary information source and on the various activities which have previously taken place there.

Remember, in the process of obtaining as much information as possible about a site, the experts you work with will consult fire insurance plans. In addition to the location of fire hydrants, these documents, which were formerly intended for insurance companies, provide information on building insurance as well as high-risk installations in their vicinity. Although their creation ceased in 1975, they’re still able to provide valuable information on the commercial activities that took place prior to the current date on the land you’re concerned with.

Obviously, the commercial activities currently taking place on the site will also be taken into account. Let’s not forget to mention that interviews should be carried out with site owners or tenants in order to obtain any information likely to assess the probability that contaminants are present in the soil.

Phase 2- environmental characterization

During the second phase of the project, the presence of soil contaminants will be confirmed or ruled out. To do this, first experts need to locate underground infrastructure and collect soil samples as well as surface or groundwater.

Then, these samples will be analyzed in a laboratory and the resulting data used to determine the nature of the pollutants found in the soil. Subsequently, recommendations will be made on the basis of these found and identified contaminants as well as the specificities of the site in question.

Phase 3- environmental characterization

Now that the soil or water contaminants have been identified, it’ll be necessary to assess the extent of the problem. This will require the process of what’s referred to as a "sampling pattern."

The area of ​​contaminated land will be determined, and this includes its depth and volume. During this phase, drilling will be carried out at strategic locations.

Phase 4 - site rehabilitation

In the event that a high concentration of contaminants is detected (exceeding the standards established by the Ministry of the Environment and the Fight against Climate Change), it’ll be necessary to rehabilitate the site. To do this, two options are available: ex-situ rehabilitation and in-situ rehabilitation.

In the first case, rehabilitation measures will consist of removing any contaminated soil or water. As for in-situ rehabilitation, this aims to treat the soil without dismantling infrastructure or excavating any of the affected soil. Rather, decontamination is done by injecting biological or chemical products into the soil. Due to the reaction of these products with the contaminant, the latter will be destroyed and then transformed into salt, water or carbon dioxide.

In order to determine which method to use, certain parameters must be taken into consideration:

• The nature of contamination: organic or inorganic/soluble or insoluble

• The location of contamination: close to the surface or located deeper

• The estimated time for cleaning the premises

• The composition of the soil (clay, sandy or silty)

• The current use of the land (vacant, operated or built)

Looking for more info about this subject? Check out the following article: The average cost of a decontamination project.