PROJECT DESCRIPTION
BACKGROUND
Soil pollution is one of the main environmental problems in Europe and worldwide. Heavily polluted soils represent a serious threat to public health. They cause pollution of groundwater, hamper the functionality and health of agricultural areas, and reduce biological diversity. European Commission data indicates that 16% of the EU land area is affected by degradation. Hence soil remains one of the top priorities of EU environmental policy.
In the Upper Mežica Valley, the soil is heavily polluted with lead and other toxic metals due to centuries of mining. It has been estimated that around 350 000 m2 should be cleaned in order to ensure a healthy living environment for local inhabitants.
The urgent need for viable, sustainable remediation technology is most critical for soils contaminated with toxic metals such as Pb (lead) and Cd (cadmium) because existing technologies are only partially successful.
OBJECTIVES
The LIFE ReSoil project would demonstrate an innovative technology for soil washing that removes most toxic metals and organic pollutants. Metals would be removed after complexation with chelant ethylenediamine tetraacetate (EDTA). This method is soil friendly and enables reuse of remediated soil as a plant substrate. However, to date it has only been tested on a laboratory or pilot scale. The main project objectives were:
- To scale-up this technology to enable large scale remediation of soils;
- To assure the cost-effectiveness of the new technology - under 50 €/t for treatment of heavily polluted soil (over 5 000 mg Pb/kg);
- To prepare a priority remediation list of contaminated locations in the Upper Mežica Valley;
- To up-grade the technology for treatment of soils dually contaminated with both toxic metals and organic pollutants.
RESULTS
The LIFE ReSoil project demonstrated a pilot remediation plant that was able to treat up to six tonnes of contaminated soil a day from the Meža Valley at a fixed cost of €53 per tonne. The pilot plant removes metals after complexation with chelant ethylenediamine tetraacetate (EDTA), which enables re-use of remediated soil as a plant substrate. The project team showed that the remediated soil could be safely used for homegrown vegetables, setting up a demonstration garden and analysing the crops produced.
The project also confirmed that EDTA is the best available technique for remediation of garden soils that have been contaminated primarily with toxic metals, when quick remediation is required. Feasibility studies showed that the technology can be scaled up for wider implementation. To ensure the continuation and replicability of the project, the project team drew up a priority remediation list of contaminated locations in the Upper Mežica Valley. It also produced a detailed financial and operational plan for soil remediation in the region that was distributed to local and national decision-makers.
The project team estimated that for a scaled-up plant with a daily capacity of at least 50 tonnes, the total cost of soil remediation is €153 per tonne. This figure compares favourably with existing alternatives, such as disposal in landfills, soil washing, phyto-remediation and fixation (immobilisation) of contaminants. Moreover, the technology has faster remediation times and generates fewer emissions. However, the pilot was operational for only seven months and not the planned 26 months. As a result, just 50 t of contaminated soil was remediated (2 340 t were foreseen), and 300 m2 of land reclaimed (7 500 m2 was foreseen). Finally, the remediation plant created new permanent jobs for the local population.
Further information on the project can be found in the project's layman report (see "Read more" section).
