Good practice:

MÉTABOLISME URBAIN project - A good exemple of social urban mining

The Urban Metabolism project led by Plaine Commune, a public territorial establishment that includes 9 cities north of Paris, aims to implement the reuse and recycling of construction materials and to develop circular economy channels through the mobilisation of the territory's endogenous material and human resources. A more reasoned management of resources is necessary, particularly building materials, in order to ensure the sustainability of Plaine Commune's development model. This is an area that is facing numerous development projects (e.g. installation of infrastructures for the 2024 Olympic Games). These developments generate a lot of incoming flows for construction and outgoing flows due to demolition and rehabilitation. The projetct was launched to think about how to close the materials loop.

5 axis:
- Experimenting with an inter-construction site re-use approach for building and public works materials on 30 pilot sites
- Set up sorting, storage and recovery platforms for building site resources
- Support the deployment of local reuse/recycling channels for building and public works materials
- Develop a digital tool to make the deposits visible and account for the externalities induced by the circular economy approach implemented
- Support the development of skills among local players, from project owners to companies, through training sessions, conferences, visits, etc. and the deployment of a reuse culture among the various players and users in the area.

Plaine Commune has called on experts to carry out a diagnosis and implement an action plan. In 2017, the local authority created a full-time position dedicated to the project. They had funding from the Île-de-France region, ADEME and the Caisse des dépôts recruit a project management assistant team.

The urban mining approach has given the Plaine Commune area a lasting foothold in a dynamic of change, which reserves a central place for the subject of the circular economy on its building sites. The reuse of materials has been carried out on more than 30 construction sites in the territory and a recovery and reuse approach has been integrated into the construction project of the Olympic village for Paris 2024.

The first idea of the approach was to allocate work sites so that materials could go from one to another, but this proved to be very complicated: the delay of one site could delay the other, the material was no longer the right one, etc. The approach was therefore rethought to allow more flexibility

Social urban mining approaches are very interesting and the example of Plaine Commune can be replicated in many territories in order to enhance existing resources and create a real economy around the reuse of materials. The method used by Plaine Commune to implement its urban mining approach was designed to be replicable in other territories, which means that it is also well documented. What will really change from one context to another is obviously the type of channels to be developed, which will differ according to needs and accessible sources. The first step is to get to know what is available locally in the urban mine and the ecosystem of actors in the area. The project has highlighted the role of the local authority in creating the right conditions for the deployment of operational recycling and reuse channels.