One of the major topics in relation to circular economy in the Paris region is the management of excavated soils. In fact, soil is a major aspect of the law Climate and Resilience approved on 21st August 2021 (https://www.legifrance.gouv.fr/jorf/id/JORFTEXT000043956924). This law introduces the importance of soil as a resource and the latter should be valorized. It also converges with the importance given to circular economy in French territories and cities. Soils have been disregarded for a long period but the challenges of climate change and carbon neutrality have reintroduced them as a major potential contributor to the ecological transition.
Paris region produces around 18 million tons of excavated earth per year. The creation of the Grand Paris Express (GPE) infrastructure and the related city planning operations will generate even greater production in the coming years: it is expected that 60 million tons will be generated by the Société du Grand Paris (SGP) by 2030. Another event has shown the importance of managing large quantities of soils: the construction of infrastructures dedicated to the 2024 Summer Olympics. The figure 1 shows the estimated quantities of excavated soils by SGP expected by 2030.
Figure 1: calendar of excavated earth (in tons) by 2030 - estimation SGP
Earth Cycle is an active contributor to implement the logic of circular economy in urban planning. Introducing earth as a material for construction, landscaping and urban design will reduce the ecological footprint and decrease the ‘artificialization’ and the waterproofing of our cities. The author of this journal believes in this approach of integrated management of earth in cities.
Earth Cycle proposes to reuse and to valorize the excavated earth to produce building materials with low environmental impact (figure 2). A raw earth materials factory located in Sevran was designed and built. This factory has been producing since autumn 2021 blocks of compressed earth, mortars and coating (see pictures 3 of the factory in Sevran).
The implementation of Earth Cycle has greatly helped the earthen construction sector in France and in the Paris region. Of course, other factors have been influencing the inclusion of raw-earth techniques in public policies, notably the launch of the National Project on Earthen Construction “PN Terre”.
The opening of the factory and the UIA label gave a very positive image. The French Environment and Energy Management Agency (ADEME), working notably on climate issues, has for instance started to include earthen techniques along bio-based solutions in the eligibility criteria of relevant calls for projects.
The creation of the Sevran pilot factory is, in our opinion, only a first step. The purpose of the UIA project is to test an innovative solution, by creating a knowledge base and skills in order to then be able to generalize it.
Figure 2: Earth Cycle, an integrated project in circular economy