Professor Jean-François Audy and his team formed by Karine Bouchard, Florence Blouin, Thileli Medani and Bechir Ben Daya, have carried out a regulatory and logistical analysis of the street sweeping value chain. Discover the summary of their work.
Every winter in northern countries like Quebec, abrasives such as sand and crushed stone are spread on the road network. In spring, a quantity of these abrasives is recovered during road sweeping operations, generating a recurrent residual material (street sweepings) which is, for the most part, landfilled. The technical feasibility of a circular economy approach aimed at reusing street sweepings as abrasives the following winter has already been demonstrated on a systemic scale. However, operationalization issues remain, and this project focused on two aspects: the impact of environmental regulations and the formalization of design elements for a sustainable circular system.
In Quebec, various environmental regulations govern the management of residual materials, including sweepings. Previous studies have made it possible to compile and analyze a large bank of historical data on the chemical and geotechnical characterization of conditioned sweepings. A crucial finding emerged: according to current environmental regulations, there are only a few chemical characterization criteria that limit the empirical reuse potential of sweepings as abrasives. A new analysis of this historical database was carried out by repositioning this restriction (represented by the black square in figure 1) after rather than before the preparation of abrasives from a fraction of conditioned sweepings and virgin abrasives. Favoring a characterization of the final recycled product (figure 1-b) that will ultimately be spread on roads rather than of the input in the circularity process (figure 1-a), this theoretical approach modifies the mapping of material flows in the circularized system. The empirical potential for abrasive reuse would thus be doubled, motivating work dedicated to strict environmental regulations that are more favorable to reuse.
Figure 1: Mapping of material flows according to the characterization of conditioned sweepings (a) or recycled abrasives (b).
An initial attempt was made to develop a conceptual framework for the design of a sustainable circular system for residual materials management.Based on a review of circular economy literature specific to the residual materials field, this framework is structured around four main themes: sustainable development governance, stakeholders and contractual aspects, system capacities and resources at regional level and, finally, innovation.Although exploratory, the application of the foundations of this framework for a transition to circular sweepings management raises the need for in-depth work on circular system alternatives, particularly in terms of adapted contractual approaches, win-win mutualization and increased collaboration, including public-private partnerships. Continued research is crucial for a wise and sustainable operationalization.