Abstract
The XXIst century’s industrial agriculture is dependent on nutrients provided by synthetic fertilizers made from non-renewable resources. On the other hand, these same nutrients are contained in organic residues, of which the management results in logistical and environmental burden. Territories like the “plaine de Versailles” (FR) include both sides of this metabolic rift. This situation stems from the non-concerted actions of organic waste producers, transformers and users, constituting the core of the sociotechnical organic waste management system (OWMS). The purpose of this work is to identify the levers for initiating a concerted initiative named territorial symbiosis, based on the theoretical framework of the plausible promise. The plausible promise is the discourse of an initiating actor confronted with a specific situation, formulated to enroll other actors in a collective response to address this situation. This interdisciplinary work includes two main phases. An analysis of industrial symbiosis case studies allows to reinforce the theoretical framework of the objects of study. This phase includes a literature review of international industrial symbiosis initiatives, and an interview campaign among promoters of french industrial symbioses. The results describe, characterize and illustrate central theoretical elements - such as bioeconomic synergy patterns, the concept of territory-system, a typology of rational myths - required to design a plausible promise featuring a territorial symbiosis. A second research phase assembles these theoretical elements to study the specific situation of the plaine de Versailles. This study includes three steps : (1) the description and characterization of the OWMS, (2) the design and modeling of possible evolutions of this system and (3) the probation of a set of plausible promises by actors of the territory-system. The results of the descriptive step highlight that the OWMS is composed of two subsystems : a physical interaction system among which actors materially handle organic waste and make allocation choices (type of collection, treatment, use…), and an influence system among which actors influence these choices in ways other than direct material action (social pressure, laws, awareness raising, etc.). The design and modeling step offers a technical framework of analysis to estimate ex ante the benefit of territorial symbiosis scenarios, by coupling allocation and transformation hypotheses. Testing plausible promises featuring these scenarios show that their ability to engage actors - their performativity - depends on their level of specification and their time frame. The performativity of little specific plausible promises appears superior to that of more detailed ones, especially in long-term perspectives. These results suggest that the initiating actor doesn’t require a comprehensive knowledge of the territory-system to engage other actors in a collective process. More generally, this thesis brings a global reflection on the bioeconomic territorial symbiosis and offers a better understanding of the initiation and evolution of innovative collective actions. It questions the link between science and society, fuelling the discussions on the role of knowledge in the ecological transition.