FROM LABORATORY TO INDUSTRIAL SCALE: COMPOSTING OF POLLUTED SOILS FROM FORMER COAL INDUSTRY AND GAS PLANTS: FUTURE RESEARCH NEEDS

摘要

Activities related to coking and, more generally, to transformation of coal, have been quite varied and underwent an intense evolution from the 18th to the 20th century. The pollutants which are likely to be present in the soils at these sites depend on the type of products being made at the site, the technical knowledge at the time of production, and the environmental policy of the company. More than thirty techniques of treatment of polluted soil from similar sites have been described and summarized in reviews published on behalf of the Environmental Protection Agency (EPA) The various treatment techniques can be classified into three main categories according to their action on the pollutants: 1. chemical or physical immobilization 2. extraction from the soil matrix 3. destruction Some of these techniques can be applied in situ or after excavation (ex situ). After excavation, the polluted material can be treated on site in a confined area, or be transported off site to a center specialized in the selected technique. The environmental risk and the financial cost inherent in transport made in situ and on-site treatments often advantageous. However, the application of this type of treatment is often severely limited, in particular by the nature of the soil matrix and of the contaminants. Destructive techniques consist mainly of various thermal treatments and biore-mediation. Biological techniques are generally less expensive than the thermal treatments and have the further advantage of a positive "green image" for the general public. Bioremediation techniques do not modify the intrinsic nature of the soil, and thus revegetation can be considered after treatment. It is thus not surprising that these techniques are receiving much attention.