Enhanced Landfill Mining (ELFM) is the safe conditioning, excavation and integrated valorisation of landfilled waste streams as both materials and energy, using innovative transformation technologies and respecting the most stringent social and ecological criteria (Jones et al. 2013).
Flanders has about 2,000 landfill sites. Because of the economic situation and the prices of parent materials, the valorisation of the flows in a landfill site is currently not yet profitable for the large-scale exploitation of Flemish landfill sites. As a result, OVAM manages the stock of raw materials that is stored in landfill sites. This involves the development of a policy for the short, medium and long term.
The first step in such stock management is determining how large the stock is and where the different stocks are situated.
The various OVAM databases are the ideal starting point. The information that is stored in the land information register (register with all relevant information about land plots and soil contamination that is provided to OVAM) was brought together with the information from the database of taxes (licensed landfill sites) and the so-called POT archive. The POT archive is an inventory of land plots where potentially past activities have taken place that contaminated the soil, including landfill sites. Our database is updated continuously. After the listing of the various landfill sites in a database the first phase of mining happens, i.e. data mining.
This data mining consists of ranking the landfill sites by their ELFM potential. This estimate of potential was translated to the Flaminco model. Flaminco is a decision support model that helps determine the ELFM potential and the environmental prioritisation of landfill sites. To this goal a score system was developed per target and per criterion. Flaminco is the acronym for Flanders Landfill Mining, Challenges and Opportunities. The version Flaminco 1.0 became operational at OVAM in 2013.
The following seven criteria are taken into account:
- the type of landfill site;
- the time of dumping;
- the volume of dump material;
- the location of the landfill site, i.e. the land use;
- the distance of the landfill site to processing sites;
- the closeness of other landfill sites;
- the necessity of soil remediation.
For the last criterion, the necessity of soil remediation, an additional elaboration was prepared.
The various landfill sites are ranked on the basis of certain weighting factors by the various aspects of ELFM: waste to materials (WtM), waste to energy (WtE), waste to land (WtL) and Resource Management – intermediate storage (RM).
In this way priorities are determined and further research is conducted.
In a next step that database is completed for the priority landfill sites and further soil investigation is carried out to further refine the potential for ELFM. In a later phase we investigate the landfill sites with a high potential for ELFM in more detail before we approach the exploitation.
But first we carry out the necessary test projects.