Environmental rehabilitation: efficiency and effectiveness in soil remediation

Soil cleaning-up operations have become a priority in most western countries. In the Netherlands, in particular, a systematic effort to restore the environmental quality of polluted sites has started in the early eighties. The cornerstone of the Dutch legislation is that of restoring soil multifunctionality, which allows the cleaned site to be used for any purpose, without functional constraints. In more than ten years of application, this approach has shown some weak points. First, the costs of cleaning-up may be extremely high. Many companies tend to delay as much as possible the operations, either to delay expenditures or to wait for the development of more effective cleaning-up technologies. Second, many cleaning-up techniques achieve very good results in terms of soil quality, but result into a transfer of pollution to other environmental media (for instance, air and water) and require an intensive use of scarce resources (for instance, energy, groundwater and space). Third, in many instances the site has a unique destination, an industrial site for instance, and cleaning-up beyond the level strictly necessary is very cost-inefficient. These considerations have lead to the development of a new approaches for soil cleaning-up and to the development of methodologies and instruments for addressing effectiveness and efficiency in soil remediation. The paper shows a Decision Support System which assists the planning of cleaning-up operations on the basis of: (1) their effectiveness in reducing the risks for the specific needs of the site; (2) their capacity of minimising the negative influences on the environment and on the depletion of scarce resources; (3) the possibility of minimising the costs of operation and of timing the cleaning-up investments. The paper focuses on the environmental quality part, showing how the negative influences of cleaning-up operations can be taken into