Microorganisms and nanoparticles
NANOMICRO is a bioremediation project for soils involving the injection of exogenous microorganisms that are capable of feeding on the pollution present in these soils. Substrates enabling the correct development of exogenous and endogenous microrganisms (c-to-d present in polluted soils) are injected at the same time as the exogenous microorganisms. The original idea for the NANOMICRO project is to use nanoparticles to stimulate the growth and activity of exogenous microrganisms.
In order to understand the progress that has been made in terms of the depollution of soils, it is neccessary to take a look at the pollution itself. Pollution is a major problem because soils keep chemical products in their “memory”: organic pollutants such as dioxins, PCBs (polychlorobiphenyls) or PAHs (polycyclic aromatic hydrocarbons) as well as high levels of heavy metals such as lead, fertilizers, insecticides, antifungal products as well as weed-killers affect soils. Soils are an essential element of biodiversity because they contain 80% of the entire biomass. In the light of these facts and the urgent need to preserve these spaces, the European Commission launched a thematic strategy for the protection of soils which was adopted in 2007. Other local initiatives have also been initiated. In Wallonia, a decree relating to the remediation of soils has been in existence since 2004 completed by another decree dating from the end of 2008 relating to soil management, sets out a basis for the coordinated treatment of potentially polluted soils, while previously, the legislation only covered two kinds of sites: dumps and service stations. In addition, increased funding has been allotted to the restoration of sites earmarked for redevelopment (SAR) in the context of the Marshall Plan. It is in this context that the project NANOMICRO is to be seen, financed jointly by the Wallonia Regional Government and two industrial companies SANIFOX (coordinator of the project) and Artechno(4). The academic partners to the project are the Wallonia Centre of Industrial Biology(5) and the Department of Chemical Engineering – Nanomaterials Catalysis and Electrochemistry to which Stéphanie Lambert-Jamoulle, who is a research associate at the FNRS and also an assistant lecturer, belongs. These two research laboratories belong to the University of Liege. The NANOMICRO project was launched in January 2013 for a duration of 4 years. It aims to study and test the interaction between nanoparticles and microorganisms and their impact on the depollution of aromatic hydrocarbons in soils. The first results are just beginning to be published (6).
Participating in the perfection of bioremediation techniques
“ The basis of the project is to carry out what is called the bioremediation of soils which involves injecting polluted soils with microorganisms (in this case called exogenous microorganisms) capable of feeding on the pollution that is present in the soils. Substrates enabling the correct development of exogenous and endogenous microrganisms (c-to-d present in polluted soils) are injected at the same time as the exogenous microorganisms” explains Stéphanie Lambert-Jamoulle. The original idea for the NANOMICRO project was to use nanoparticles to stimulate the growth and activity of exogenous microorganisms. Bioremediation presents non-negligible advantages: reduced costs, total efficacy on volatile residual pollutants and on non-chlorinated pollutants such as lubricants, oils and a large number of aromatic hydrocarbons but also some chlorinated pollutants. In addition, it can be carried out in situ, requiring neither the excavation of soils nor heavy logistics particularly in terms of transport. It should be noted that the choice of treatments used is influenced by the intended future use of the terrain concerned. If it involves real estate operations, the time necessary before the remediation of the land is an essential parameter. In this case there will be little or no place for treatments in the long-term. The excavation and exportation of polluted soils are therefore chosen in the majority of cases. This solves the problem locally but raises the question of the treatment of the excavated soil. Bioremediation would seem to be the ideal solution in comparative terms. The main disadvantage lies in the duration of the treatment required, estimated to be about four years in Belgium for urgent situations and fifteen years in the other cases. This disadvantage is not to be taken lightly when we know the areas that need to be treated.
(1) Regional Government of Wallonia decree relative to the «remediation of polluted soils and active economic sites to be renovated » adopted on April 1st 2004
(2) Regional Government of Wallonia decree adopted on December 3rd 2008 and implemented on May 18th 2009.
(3) €243M have been allotted to the renovation of 37 polluted SARs (515 hectares) and €110 M to the renovation of 121 low-priority or slightly polluted SARs (258 hectares). In addition to this there is also the Marshall plan 2.vert which plans to provide €125M and €100M for the renovation of 13 polluted SARs and 70 non-polluted or slightly-polluted SARs. (Source : http : //etat.environnement.wallonie.be, tableau de bord 2010, p. 192)
(4) Artechno, created in 1999, is a spin-off-type company from research carried out at the Wallonia Centre for Industrial Biology.
(5) The Wallonia Centre for Industrial Biology develops research into biotechnology, from the initial stage to the finished product; it was jointly created in 1988 by the University of Liege and the University Faculty of Agronomic Sciences at Gembloux, today, Gembloux Agro-Bio Tech/University of Liege.
(6) Development by the sol–gel process of highly dispersed Ni–Cu/SiO2 xerogel catalysts for selective 1,2-dichloroethane hydrodechlorination into ethylene, Microporous and Mesoporous Materials, Pirard Sophie, Mahy Julien, Pirard Jean-Paul, Heinrichs Benoît, Raskinet Laurent, Lambert Stéphanie, ref. Orbi : http://hdl.handle.net/2268/172092
W. Wannoussa, T. Masy, S. D. Lambert, B. Heinrichs, L. Tasseroul, A. E. Al-Ahmad, F. Weekers, P. Thonart, S. Hiligsmann, Journal of Water Resource and Protection, 7 (2015) 264-277."Effect of iron nanoparticles synthesized by a sol-gel process on Rhodococcus erythropolis T902.1 for biphenyl degradation".
W. Wannoussa, S. Hiligsmann, T. Masy, S. D. Lambert, B. Heinrichs, A. E. Al-Ahmad, F. Weekers, P. Thonart, Journal of Sol-Gel Science and Technology, press article. "Effect of metal ions and metal nanoparticles encapsulated in porous silica on biodegradation kinetics for biphenyl".