Assessment of the ecocompatibility of waste disposed of or reuse in civil works: a pluridisciplinary method for a scenario-based approach
The disposal and reuse of waste (e.g., reuse of waste material for civil engineering or construction) are subjected to regulations that are mainly based on the best available technologies. They usually do not directly take into account the impact on human health and on the environment due to a lack of technical data in this field. Recent emphasis on the need to evaluate this impact has resulted in the necessity for new evaluation tools. The ADEME (the French Agency for Environment and Energy Management) launched a research programme in 1995 called "Waste Ecocompatibility" to define a reliable methodology for measuring the impact of waste storage or reuse scenarios. This method could be used as a decision tool for environmental policy makers. It can also be used to determine what the acceptable levels of waste dumping or waste-based civil works are, while still being ecocompatible. The approach to set up this methodology is based on the concept of ecocompatibility. This is now defined as the situation where the pollutant flux from waste, either disposed of or reused, under specified conditions (physical, hydrogeological, chemical and biological conditions), is compatible with the environmental acceptance of the concerned receptor mediums. This definition integrates the evaluation of the pollutants emitted from the waste, the transport of these pollutants from the waste to the receptor media and their impact on the target receptor media. An introduction to the research program was proposed by Mayeux and Perrodin (1996) and Gobbey and Perrodin (1999) in previous papers. The experimental sections were taken from Barna et al. (2000a), Barna et al. (2000b) and Ferrari (2000) concerning the emission pollutant term and the assessment of waste ecotoxicological properties. Experimentation dealing with the environmental impact on the soil and aquatic media was developed by Canivet (2001) and Poly (2000). This program led to an operational methodology introduced by the ADEME (2000). The general steps in conducting the ecocompatibility assessment of waste disposal or reuse scenarios are: 1) the preliminary description of the studied scenario; 2) the implementation of tests and measurements; and 3) the assessment of the global waste scenario ecocompatibility. Ecocompatibility assessment is a multidisciplinary approach requiring researchers in biology, ecotoxicology, ecology, chemistry, hydrogeology, geology, etc. Some of them are specialists in the study of waste characterisation and waste leaching behaviour, especially with respect to investigations on long-term predictions. Researchers in charge of the impact term are skilled in the environmental impact assessment of complex effluents on soil, plants, micro-organisms, soil fauna and benthic invertebrates. In this paper, we stress the critical role of the scientific manager in the multidisciplinary work of an ecocompatibility assessment. The scientific manager must make the general problems understandable for each researcher involved. It is necessary to translate the general question into a series of specific questions related to each term of the methodology. To take advantage of a multidisciplinary study it is necessary to encourage and facilitate communication and discussion. If this is not efficient, each team will focus on its specific objective without taken into account data from the other teams. A lack of effective interactions between the involved researchers and the scientific manager will lead to a series of individual studies that are not of interest with regards to the general question. Similarly, it is essential that the various results lead to a joint discussion to draw a common conclusion.