PROJECT DESCRIPTION
BACKGROUND
Soil pollution constitutes one of the main threats to the health of ecosystems in Europe. There are about 2.8 million sites potentially contaminated, with 650 000 of them being identified as requiring remediation; among them, only 15% have been treated.
Recent estimates found that mineral oil and polycyclic aromatic hydrocarbons, also commonly referred to as Petroleum Hydrocarbons (PHs), amount to around 35% of all contaminants present in European soils. Soil remediation technologies currently available to tackle organic contaminants mainly consist of landfilling, physicochemical treatments (thermal desorption) and conventional bioremediation. The first 2 solutions constitute costly and energy-intensive approaches. Landfilling only consists of displacing untreated polluted soil to confinement. Thermal treatment has the clear advantage of being a short time process, but is highly energy consuming, leading to significant greenhouse gas (GHG) emissions. Moreover, it results in the generation of a “dead” – albeit cleaner – soil.
Conversely, bioremediation can be performed on-site on excavated soil arranged in biopiles. These biopiles are engineered to stimulate either indigenous or allochthonous bacterial activity and to boost biodegradable metabolism, thus ensuring the breakdown of organic pollutants. This remediation technology is the most environmentally-friendly solution available on the market, as it is less energy-intensive and has no detrimental impact on soil functions. However, its major limitation is the low removal efficiency of long-chained PHs: while thermal desorption has removal rates over 99%, bioremediation percentages might be as low as 20% for weathered PHs. Mycoremediation can be an alternative that retains the benefits of current bioremediation techniques while significantly increasing the removal efficiency. However, it is a technology that had only been studied at a lab- and bench-scale before the LIFE MySOIL project.
OBJECTIVES
The LIFE MySOIL project aimed to validate a competitive technology to achieve recalcitrant PH removal percentages to close to those currently achieved with thermal treatments, but with reduced energy requirements, lower GHG emissions, reduced costs, and limited reagents to nutrient addition. Specifically, the project aimed to push forward the use of an emerging on site/ex-situ bioremediation technology: novel biopiling structure inoculated with specific fungal inoculum (mycoremediation).
The process would also enable the valorisation of an abundant agricultural waste (spent mushroom substrate). The objectives of the project were fully in line with the current and the upcoming EU Soil Strategy, aiming to remediate contaminated sites so that by 2050 soil pollution will no longer pose a health or environmental risk.
RESULTS
The beneficiaries successfully demonstrated the feasibility of mycoremediation for both PH removal and the recovery of the soil’s biological functions on a large scale. Some of the project's main achievements include:
- PH degradation ranging from 40% to over 70% across the demo sites; while total removal was comparable in both mycopiles and conventional biopiles, mycopiles showed faster degradation, particularly during early treatment phases, and significant degradation of both aromatic and aliphatic PHs,
- ecotoxicity reduction of over 75% in soil leachates, with seed germination increasing by 60-100%,
- reduction of the environmental footprint by 60-90% compared to conventional thermal desorption,
- costs reduced by 40-85% compared to the costs of conventional thermal desorption.
These results confirm that mycoremediation is an optimal solution for the rapid degradation of heavy PHs, as well as other organic pollutants.
Furthermore, the project produced a comprehensive set of guidelines and recommendations to support the efficient implementation of this technology and to promote the harmonisation and reinforcement of the EU soil legislation.
