How to start a journey towards circularity

REFLOW has compiled, through its 6 pilot cities, a set of methodological insights to support cities on their first steps towards circularity.

Establishing a city-wide Circular Economy requires first to map material flows within the city in order to assess its production capacity. The Paris pilot, which focuses on wood’s circularity, provides you here with some first elements of methodology and initial knowledge, to help you to start your material flow research (a new blog post will come later to go further through this methodology).

The report – Growing Map of City Production Capacity and Material Flows  – provides a methodological approach illustrated through each pilot’s material flow (wood, plastic, textile, wastewater heat, urban energy and food waste) to obtain a first level of understanding of the material journeys and processes undergone throughout their life cycle.

MFA is key

The most common tool used by organizations to visualise material flows within a system, is called “Material Flow Analysis” (“MFA”). It is basically a systematic and efficient analysis of material and substance flows within  a production system. See it as a very straightforward but effective way to  analyse and improve both the productivity and the impact of any activity. MFA works for almost any system and can be applied to various types of actors (plants, workshops, factories, housing, fablabs, cities…) but also on products (commonly known as a life cycle assessment), as long as some material resources are engaged.

MFA allows stakeholders to have a clear visibility of the city production capacity, and aims to reduce the number of non-value adding activities, but also to minimise handling damage, to reduce inventory, to decrease lead times and even allows to improve customer deliveries and services. It can take any shape and highly depends on the context.

What we suggest here is to start with a preliminary data collection. This is usually the first step toward an MFA.

How to build a preliminary data collection ?

Where to start? Which information should we prioritize and which level of details should we first target?

Keep in mind that you don’t need to be a data analyst or an engineer to start this process, as at this stage there is no need to go deep into details. Your first goal is to get a rough grasp of the situation. Keep also in mind that your document don’t have to be visually appealing at this stage, you should focus on the system first, not on the design. You can start with a pad and a pen for instance. You can also use some mind mapping tools (such as XmindMindmeister, or Wise mapping) or graphic softwares like GimpIllustrator, VectR or Canvas). 

Let’s imagine you plan to assess your city wood’s stream:

  • Start by doing some basic research to gather generic data related to the wood’s ecosystem and its industry. It is also a good way to identify the most obvious steps and actors of this system.
  • Map the ecosystem and try to catch the main flows and connections between the different Don’t forget to explore all the possible journeys the material can take.
  • At this stage you should already be able to validate a first draft of the material stream within your city. It may also highlight the lack of information on a few pieces of the
  • Go further now, by interviewing related actors. This very important step will allow you to do some fact checking and collect new insights but also to potentially discover new actors, flows and processes. You can also deep dive into some online open data resources.

Once the missing pieces have been identified, you may start with your preliminary data collection.

The Paris example

This illustration displays all possible paths wood can take within the Paris ecosystem. This figure must be read from left to right:


Each different color represents a different path and possibility within the Paris ecosystem. The green point represents the wood life cycle starting point. The first step is “raw wood”. The raw wood first goes through a manufacturing process, where the wood is transformed into parts or final furniture/objects. Then, the material is used by different actors, and use either for temporary construction or events.

Once used, the wood is either discarded, stored, or re-used in situ/ex situ. Discarding the wood implies that the wood will either be recycled, used for energy recovery, or not valorised at all. Alternatively, storing the wood offers many possibilities for re-use and up-cycling. These paths offer many business opportunities and are potential journeys the REFLOW project wishes to explore.

Once discarded, according to ADEME (the French Agency for Environment and Energy Management), the wood is discriminated into categories depending on their treatment. When the wood is not treated (raw), it is grinned into specific sizes and the outcome, depending on the size, can turn into wooden chips and/or sawdust, or wooden pellets and/or compacted sawdust. The former one can then become either litter, stable floor, mulching or compost. The litter, once used, can also be turned into compost. The latter one, wooden pellets and/or compacted sawdust, are used as hog fuel. The material is burnt for energy recovery. Those are different ways to recycle raw wood. When the wood is treated, it is also grinned into specific sizes, but the outcome is compressed into panels, to become OSB panels, MDF or chipboard.

When the wood is stored, users have the opportunity to reuse it, as a second-hand asset. The wood re-enter its life cycle at the “use” step.

When the material is deteriorated, from storage, the material can undergo a reconditioning process, and re-enter its life cycle at the “use” step. The reconditioning process can also precede a re-manufacturing process, during which the material is transformed again for a second life. Again, from this step, the material re-enters its life cycle at the “use” step.

The report – Growing Map of City Production Capacity and Material Flows – focuses on developing for each pilots’ material (wood, plastic, textile, wastewater heat, urban energy and food waste) a first level understanding of the material journeys, and of the material key processes, undergone during its life cycle.

Paris Pilot

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