Wallonia has many sites inherited from its rich industrial past. The management of these former industrial sites, their clean-up and the requalification of these spaces is a challenge for Wallonia and represents a priority for the government in the regional policy declaration (DPR) published in July 2014. The recovery approach is described in the Walloon code of best practices (CWBP). The choice of appropriate management methods for the sites requires good knowledge of the environments concerned. Very precise localisation and characterisation of the affected zones is required. These stages may be extremely long and costly, which slows down the rehabilitation of the sites concerned.
For several years, analysis tools have been used to measure contaminants on construction sites. These tools were designed with the aim of providing rapid and low-cost responses. Without claiming to replace laboratory measurements, which will remain the references, the implementation of this type of approach is able to multiply investigation points and thus refine the diagnosis/characterisation phase, localise “hot spots” more quickly, direct “critical batches” of land towards the laboratory… all while reducing costs. This method may lead to a reduction in the site’s “orientation/characterisation” budget by reducing pre-development/pre-recovery stages for the benefit of post-characterisation/clean-up stages.
This project is part of the territory’s approach concerning sustainable, intelligent, and responsible management of the territory. It is part of a project to requalify spaces which are historically “anthropic” and is based on the development of a workshop in partnership with a manufacturer: Roton environnement. The industrial site concerned, a legacy of the mining of coal, guarantees an availability at least equal to a decade. In this context, it is perfectly possible to test tools and methods for optimising time and resources for sustainable management of the site.
To develop a responsible approach to the management of anthropised soil through the use of ground management tools which: – by allowing rapid measurements, leads to a reduction in characterisation times;
- by allowing the multiplication of measurement, allows more precise characterisation of polluted sites and soils;
- and this at a low cost.
The project is based on the development of a workshop site. It proposes quantifying the advantages and disadvantages of the implementation of contaminant measurements on the ground for the management of former industrial sites; the aim is to find an acceptable compromise for site managers and administration, between the cost of investigations required to rehabilitate a site and performance times. As the site has received coal-related activities, the pollutants targeted by the study will be primarily PAHs (polycyclic aromatic hydrocarbons) and hydrocarbons (mineral oils).
One or more analytical techniques will be tested from among those set out in paragraph 4.2 (state of the art). The choice will be made based on the budget available and the conclusions of step 1 described below.
The project will take place in several stages:
- Stage 1
- updating of the existing state of the art concerning on-site contaminant measurement tools to validate the choice of tool(s) to be tested: the scientific and technical literature will be tested to identify the different solutions available to us. It will also be necessary to contact potential suppliers and, by increasing the various information and our needs, finalise the acquisition of the material for the study. Depending on the number of options available to us, it may be preferable to hire equipment rather than purchase it.
- At the same time, an inventory of the site-related knowledge available will be required. Mapping will be carried out to assess the scope of the zones impacted from the georeferenced data on the characterisation of existing contaminants, which will be made available by the site’s owner. This will constitute the study’s starting point with the aim being to develop this map by refining the scope of the zones contaminated or not by the multiplication of measures made possible through the use of field tools.
- Stage 1
- Stage 2
- Management of the ground measurement device(s): once the devices are received, personnel will need to learn how to use them. Therefore, the measurements will be validated at the laboratory (reference standards and soils) which will help with understanding the device’s response mode and estimating the degree of confidence in the responses it provides. This amounts to calibrating the instrument and estimating the accuracy and precision of the measurement. This stage will define the optimal conditions for using the device.
- Updating of the measurement: once the device is available, it will be essential to verify that its use is compatible with the matrices of interest to the study, which is to say polluted soils. The responses given by the field device will be compared to the data given by the laboratory devices. Samples taken on site will be homogenised, separated into two batches to undergo a specific protocol: either the “ground” protocol or the “lab” protocol applied routinely by the laboratory. A study of the correlation between the two series of results will allow us to set and validate the conditions of use for the ground device on the matrices concerned.
- Stage 3
- Implementation on the ground: the responses using the ground device being managed, it will then be necessary to verify and set the feasibility of the measurements on the ground. We will then have to look at several practical details such as the autonomy of the device in terms of energy, the accessibility of the measurement points, the need or not of a development on site, etc. At the end of this stage, a protocol for the implementation of on-site measurements will be drafted.
- Comparison of approaches: performance of additional characterisation of the study site according to the CWPB’s procedures. In parallel, characterisation of the same zone will be carried out using ground measurements. Both approaches will be assessed in terms of time taken, how long it takes to receive the results, cost, and mapping of the contamination of the site will be carried out.
- Stage 4
- After stage 4, a comparison of the two approaches (ground and lab) will be carried out. It will be possible to identify the strengths and weaknesses of each of them and to assess the interest of opening up current procedures in Wallonia to these new practices.
- Based on the conclusions drawn, a proposal to modify official management procedures for sites in Wallonia may be prepared in line with the approach. Laboratory analysis will not systematically be replaced by ground analyses, but the aim is to optimise the study period and the use of budgets.
- Without predicting the project’s outcomes by way of illustrating the foregoing, we can assume that the use of ground tools is recommended in one stage or another of the procedures described in the CWBP, during the orientation study or even the monitoring of processing, for example.
- Stage 2
The project is a partnership between various ISSeP laboratories (UMS for “development and ground laboratory comparison” aspects; the DSAR department and the reference lab for “development of the approach described in the CWBP” aspects and potential modifications to official procedures) and a manufacturer providing a site and managing some of the ground investigations (€30k).
The “Moerman budget” requested for the performance of the project is estimated at €747k over 3 years, with €207k for the 1st year, €299k for the second, and €241 for the last year.