PARENT SESSION

6E - Life cycle management
Poster Hall
8:30 AM - Monday, 28 April 2003
Chair: Saur, K.¹, ¹
Co-chair: Frankl, P.², ²

(MOP/218) LCA of Aboveground Bioremediation of Diesel-Impacted Soil.

Laurence, Toffoletto¹, Louise, Deschênes ¹, Réjean, Samson¹, ¹ CIRAIG - Ecole Polytechnique de Montreal, Montreal, Quebec, Canada

ABSTRACT- Primary and secondary environmental impacts associated with bioremediation of diesel-contaminated sites were assessed using a life cycle assessment (LCA). The case study was the remediation of 8000 m³ of subsurface soil impacted with an average of 6145 mg of diesel fuel/kg soil during a two-year period. Two scenarios were compared; the construction of a single-use treatment facility on site or the use of a permanent treatment centre that can accept 25000 m³ soil/year. Moreover, since bioremediation is never 100% efficient, different efficiency scenarios, including the transportation of partially treated soil to landfill were analyzed. The primary impact of residual soil contamination was determined by developing a specific characterization factor (ecotoxicity and human toxicity categories in the EDIP method) based on the toxic components of diesel. One major observation was the fact that the soil itself is responsible for an important fraction of the system's total impact, suggesting that it is beneficial to reach the highest level of remediation. The reutilization of the treatment facility is also an important issue in the overall environmental performance of the system. In the case of a single-use treatment centre, the analysis showed that site preparation (asphalt paving) was the major contributing stage to the overall impact, mainly due to the ecotoxicity impact category. Results indicated that off-site transport and the biotreatment process did not contribute notably to the level of environmental impact. The use of a permanent treatment centre is preferred since it allows a significant decrease of the remediation impact. However, when soil had to be transported for a distance greater than 200 km from the site, it was more beneficial to treat the soil on site. LCA was found to be an efficient tool to manage contaminated soil in a sustainable way. However, because of the major contribution of soil residual contamination, additional spatial and temporal data should be collected and integrated in the substance characterization factors.

Key words: life cycle assessment, bioremediation, primary impact, secondary impact