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gestion des déchets, waste management

Waste management: decentralizing for better management

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Reducing the environmental impact of waste and encouraging its reuse calls for a new approach to its management. This requires the modeling of circuits on a territorial scale, and the improvement of collaboration between public and private actors.

Territorial waste management is one of the fundamental aspects of the circular economy. Audrey Tanguy,1 a researcher at Mines Saint-Étienne, is devoting some of her research to this subject by focusing on the development of approaches to enable the optimal management of waste according to its type and the characteristics of different territories. “The principle is to characterize renewable and local resources in order to define how they can be processed directly on the territory,” explains Audrey Tanguy. Organic waste, for example, should be processed using the shortest possible circuits because it degrades quickly. Current approaches tend to centralize as much waste as possible with a view to its processing, while circular approaches tend towards more local, decentralized circuits. Decentralization can be supported by low-tech technologies, which optimize local recycling or composting in the case of organic waste, especially in the urban environment.

The research associated with waste processing therefore aims to find ways to relocate these flows. Modeling tools can help to spatialize these flows and then provide guidance for decision-makers on how to accommodate local channels. “Traditional waste-processing impact assessment tools assess centralized industrial systems, so we need to regionalize them,” explains Audrey Tanguy. These tools must take the territorial distribution of resources into account, regardless of whether they are reusable. In other words, they must determine which are the main flows that can be engaged in order to recover and transform materials. “It is therefore a question of using the appropriate method to prioritize the collection of materials, and to this end, an inventory of the emission and consumption flows needs to be drawn up within the territory,” states the researcher.

Implementation of strategies in the territories

In order to implement circular economy strategies on a territorial scale, the collaboration of different types of local actors is essential. Beyond the tools required, researchers and the organizations in place can also play an important role by helping the decision-makers to carry out more in-depth investigations of the various activities present in the chosen territory. This enables the definition of collaborative strategies in which certain central stakeholders galvanize the actions of the other actors. For example, business associations or local public-private partnership associations promote policies that support industrial strategies. A good illustration is the involvement of the Macéo association, in partnership with Mines Saint-Étienne, in the implementation of strategies for the recycling and recovery of plastic waste in the Massif Central region. It acts as a central player in this territory and coordinates the various actions by implementing collaborative projects between companies and communities.

The tools also provide access to quantitative data about the value of potential exchanges between companies and enable the comparison of different scenarios based on exchanges. This can be applied to aspects of the pooling of transport services, suppliers or infrastructure. Even if these strategies do not concern core industrial production activities, they lay the foundations for future strategies on a broader scale by establishing trust between different actors.

Reindustrialisation of territories

“We assume that in order to reduce our impacts, one of the strategies to be implemented is the reindustrialization of territories to promote shorter circuits,” explains Natacha Gondran,1 a researcher in environmental assessment at Mines Saint-Étienne. “This may involve trade-offs, such as sometimes accepting a degree of local degradation of the measured impacts in exchange for a greater reduction in the overall impact,” the researcher continues.

Reindustrializing territories is therefore likely to favor the implementation of circular dynamics. Collaboration between different actors at the local level could in this way provide appropriate responses to global issues concerning the pressure on resources and emissions linked to human activities. “This is one of the strategies to be put in place for the future, but it is also important to rethink our relationship with consumption in order to reduce it and embrace a more moderate approach,” concludes Natacha Gondran.

1 Audrey Tanguy and Natacha Gondran carry out their research in the framework of the Environment, City and Society Laboratory, a joint CNRS research unit composed of 7 members including Mines Saint-Étienne.

Antonin Counillon

This article is part of a 2-part mini-series on the circular economy.
Read the previous article:

Economics – dive in, there is so much to discover!
économie circulaire, impact environnemental

Economics – dive in, there is so much to discover!

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To effectively roll out circular economy policies within a territory, companies and decision-makers require access to evaluation and simulation tools. The design of these tools, still in the research phase, necessarily requires a more detailed consideration of the impact of human activities, both locally and globally.

“The circular economy enables optimization of the available resources in order to preserve them and reduce pressure on the environment,” explains Valérie Laforest,1 a researcher at Mines Saint-Étienne. Awareness of the need to protect the planet began to develop in earnest in the 1990s and was gradually accompanied by the introduction of various key regulations. For example, the 1996 IPPC (Integrated Pollution Prevention and Control) Directive, which Valérie Laforest helped to implement through her research, aims to prevent and reduce the different types of pollutant emissions. More recently, legislation such as the French Law on Energy Transition for Green Growth (2015) and the Anti-Waste Law for a Circular Economy (2021) have reflected the growing desire to take the environment into account when considering anthropic activities. However, to enable industries to adapt to these regulations, it is essential for them to have access to tools derived from in-depth research on the impacts of their activities.

Decision-support tools for actors

To enable actors to comply with the regulations and reduce their impacts on the environment, they need to be provided with tools adapted to issues that are both global and local. Part of the research on the circular economy therefore concerns the development of such tools. The aim is to design models that are precise enough to be able to characterize and evaluate a system on the scale of an individual territory, while also being general enough to be adapted to territories with other characteristics. Fairly general methodological frameworks can therefore be developed, within which it is possible to determine criteria and indicators specific to certain cases or sectors. These tools should provide decision-makers with the information they need to implement their infrastructures.

At Mines Saint-Étienne and in collaboration with Macéo, a team of researchers is focusing on the development of a tool called ADALIE, which aims to characterize the potential of territories. This tool creates maps of different geographical areas showing different criteria, such as the economic or environmental criteria of these territories, as well as the industries established in them and their impacts. Decision-makers can therefore use this mapping tool as the basis for choosing their priority activity areas. “The underlying issue is about being able to ensure that a territory possesses the dimensions required to implement circular economy strategies, and that they are successful,” Valerie Laforest tells us. In its next phase, the ADALIE program then aims to archive experiences of effective territorial practices in order to create databases.

For each territorial study, the research provides a huge volume of different types of information. This data generates models that can then be tested in other territories, which also enables the robustness of the models to be checked according to the chosen indicators. These types of tools help local stakeholders to make decisions on aspects of industrial and territorial economics. “This facilitates reflection on how to develop strategies that bring together several actors affected by different issues and problems within a given territory,” states Valérie Laforest. To this end, it is essential to have access to methodologies that enable the measurement of the different environmental impacts. Two main methods are available.

Measurements of impact on the circular economy

Life cycle analysis (LCA) aims to estimate environmental impacts spanning a large geographical and temporal scale, taking account of issues such as distance transported. LCA seeks to model all potential consumptions and emissions over the entire life span of a system. The models are developed by compiling data from other systems and can be used to compare different scenarios in order to determine the scenario that is likely to have the least impact.

Read more on I’MTech: What is life cycle analysis?

The other approach is the best available techniques (BAT) method. This practice was implemented under the European Industrial Emissions Directive (IPPC then IED) in 1996. It aims to help European companies achieve performance standards equivalent to benchmark values for their consumption and emission flows. These benchmarks are based on data from samples of European companies. The granting or refusal of an operating license depends on the comparison of their performance with the reference sample. BATs are therefore based on European standards and have a regulatory purpose.

BATs are related to companies’ performance in the use phase, i.e. the performance of techniques is closely scrutinized in relation to incoming and outgoing flows during the use phase. LCA, on the other hand, is based on real or modeled data including information from upstream and downstream of this use phase. The BAT and LCA approaches are therefore complementary and not exclusive. For example, between two BAT analyses of a system to ensure its compliance with the regulations, different models of the systems could be created by conducting LCAs in order to determine the technique that has the least impact throughout its entire life cycle.

Planetary boundaries

In addition to quantifying the flows generated by companies, impact measurements must also include the effects of these flows on the environment on a global scale.

To this end, research and practices also focus on the effects of activities in relation to the different planetary boundaries. These boundary levels reflect the capacity of the planet to absorb impacts, beyond which they are considered to have irreversible effects.

The work of Natacha Gondran1 at Mines Saint-Étienne is contributing to the development of methods for assessing absolute environmental sustainability, based on planetary boundaries. “We work on the basis of global limitations, defined in the literature, which correspond to categories of impacts that are subject to thresholds at the global level. If humanity exceeds these thresholds, the conditions of life on Earth will become less stable than they are today. We are trying to implement this in impact assessment tools on the scale of systems such as companies,” she explains. These impacts, such as greenhouse gas emissions, land use, and the eutrophication of water, are not directly visible. They must therefore be represented in order to identify the actions to be taken to reduce them.

Read more on I’MTech: Circular economy, environmental assessment and environmental budgeting

Planetary boundaries are defined at the global level by a community of scientists. Modeling tools enable these boundaries to be used to define ecological budgets that correspond, in a manner of speaking, to the maximum quantity of pollutants that can be emitted without exceeding these global limits. The next challenge is then to design different methods to allocate these planetary budgets to territories or production systems. This makes it possible to estimate the impact of industries or territories in relation to planetary boundaries. “Today, many industries are already exceeding these boundary levels, such as the agri-food industry associated with meat. The challenge is to find local systems that can act as alternatives to these circuits in order to drop below the boundary levels,” explains the researcher. For example, it would be wise to locate livestock production closer to truck farming sites, as livestock effluents could then be used as fertilizer for truck farming products. This could reduce the overall impact of the different agri-food chains on the nitrogen and phosphorus cycles, as well as the impact of transport-related emissions, while improving waste management at the territorial level.

Together, these different tools provide an increasingly extensive methodological framework for ensuring the compatibility of human activities with the conservation of ecosystems.

1 Valérie Laforest and Natacha Gondran carry out their research in the framework of the Environment, City and Society Laboratory, a joint CNRS research unit composed of 7 members including Mines Saint-Étienne.

Antonin Counillon

This article is part of a 2-part mini-series on the circular economy.
Read more:

Waste management: decentralizing for better management

What do we know about the environmental impact of biocomposites?

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Bio-based materials are an alternative to those derived from fossil resources. They have been increasingly promoted in recent years. However, given the recent development of this sector, their real environmental impact is still relatively unknown. Joana Beigbeder, researcher in environmental analysis at IMT Mines Alès, provides an update on the life cycle analysis (LCA) of these emerging materials.

Although bio-based materials are presented as an effective alternative to their petroleum-based predecessors, the details of their environmental impact are still not well known. Plant-based materials are certainly an improvement for some impacts, such as carbon footprint, but it can be trickier when it comes to soil use or soil pollution, for example. To get to the bottom of this, life cycle analysis is an indispensable tool.

Joana Beigbeder, researcher in environmental impacts at IMT Mines Alès, is working on the life cycle analysis of these new bio-based materials, particularly biocomposites. The objective is to compare the environmental impact of different scenarios, either between bio-based and petroleum-based materials, or according to the different stages of the life cycle of the same material. The researcher says, “the focus of life cycle analysis is to study several environmental impacts in parallel and to identify possible transfers of pollution throughout the life cycle of a product”.

Different sources of impact

With regard to environmental impact, some points seem obvious. If we only look at carbon footprint, it seems obvious that bio-based materials are more beneficial than their petroleum-based cousins. But the reality is more complex because there are many variables to consider. “Carbon impact is a well-known indicator, but we must also take into account the different impacts of pollution, human toxicity, soil or water pollution or global warming”, says Joana Beigbeder. Take the automotive sector, for example. If for the same function, a part made of bio-based material has a higher weight, it will require more energy to use and will not necessarily be beneficial. “It may be a better solution from an environmental point of view, but that’s precisely what the LCA will tell us,” she says.

Some points seem more obvious, such as the consumption of fossil resources and the impact on global warming in general. Plant materials absorb CO2 during their growth, which gives them an undeniable advantage. That said, their growth implies an agricultural impact, especially on land use. “Depending on the type of crop, this can lead to soil pollution. Generally, the more fertilizers and additives that are required for growth, the less beneficial some of the impacts will be,” says Joana Beigbeder. This brings up a new issue that does not exist with petroleum-based materials.

“It’s always a case of compromising, and we look for ways to improve the process or the product,” says the researcher. “Plants, such as flax or hemp, require little or no input and are therefore a preferred option. But the material is only one area for improvement when it comes to eco-design”, she notes. To reduce the environmental impact of a product, lightening its weight and extending its lifespan are key points. This can include the reparability of the product, or even new concepts such as prioritizing the use of the product over the purchase of the product.

“There is also a question of ecological common sense, if we study a disposable product, reusable or compostable materials will be favored,” says Joana Beigbeder. One research topic includes the development of compostable diapers and band-aids, a promising step in reducing plastic pollution.

Predicting potential impacts

“Life cycle analysis study is really done on a case-by-case basis depending on the service provided by a product,” says Joana Beigbeder. To estimate the consumption of solvents or the chemical synthesis of materials, the researcher uses previous scientific publications and mathematical models. But in some areas, data is missing. “We sometimes have to use fairly strong approximations on certain impacts, but this still allows us to map trends and areas for improvement,” she maintains. This can be the case for the production of plant fibers, as well as for their disposal at the end of their use.

As these materials do not yet have a major presence on the market, there are currently no channels for processing the resulting waste. In fact, there is no data on the environmental impact of the incineration, landfill, or pollution from these newly emerging materials. “To estimate these impacts, we assimilate them to other, better-known closely-related materials on which we have data, to develop our hypotheses,” she explains. This work also generates new data for LCA such as recycling simulations for end-of-life treatment.

“Some bio-based materials are at the laboratory stage today, and it’s still hard to imagine what will happen at the industrial stage,” says Joana Beigbeder. The researcher then works on predictions: she imagines scenarios for materials that are not yet on the market and analyzes whether this has any impact on an environmental level. Also, given the recent nature of the bio-materials sector, their production will be less optimized than that of traditional petroleum-based materials which have evolved and improved. “This works against the newer materials, as they will need to go through several developmental stages,” she points out.

This research is essential for the development of sustainable alternatives to conventional materials and is part of an overall vision to meet the challenges of plastic pollution. “A lot of research is focused on the development of new materials with a smaller environmental impact. The VOICE project, for example, launched in 2018 in partnership with Innovation Plasturgie Composites, Silvadec, IMT Mines Alès and funded by ADEME, focuses on the recycling of biocomposite decking. Or the Agrobranche project, which brings together 8 French partners[1], and focuses on, among other things, the study of bio-based reinforcements from agroforestry,” she concludes. These two projects reflect the blossoming of new emerging materials and the current development of research to find sustainable alternatives to the plastic problem.

[1] Scop Agroof (coordinator), IMT Mines Alès, CIRAD BiowooEB, LERMAB, FRD, CRA Bretagne, CIRAD AMAP, INRA SPO

Tiphaine Claveau