Session 10 - Chances and Limitations of Circular Economy in a Resource Efficient Society

Convener - Christina Dornack, Martin Faulstich

Speaker Titel Abstract Kind of presentation
Christoph Wünsch The role of compost as fertilizer and soil conditioner in the waste-soil-nexus – avoiding greenhouse gas emissions and mitigating climate change  Compost from organic residues is rich in directly plant available nutrients, thus being a direct substitute for synthetic fertilizer, and hence indirectly reducing greenhouse gas emissions. Furthermore, the soil properties, such as the delayed release of nutrients, the improved soil aeration and an increased water retention capacity, can be improved by the usage of compost. These properties lead to an increase of microorganisms in the soil and enhanced plant growth, which then again increases the carbon sequestering and reduction of greenhouse gases. Moreover, is it possible to save energy, which is needed for artificial irrigation, by means of the enhanced water retention capacity. Energy used for ploughing can furthermore be reduced through improved soil aeration. Both properties thus indirectly prevent greenhouse emissions. Compost application as part of a sustainable circular economy closes the material cycle, increases carbon sequestering in the soil and in plants, as well as indirectly saves energy. All this contributes to the reduction of greenhouse gases in the atmosphere and hence mitigates climate change. Within the presentation/contribution the mitigation potential of greenhouse gas emissions by substituting synthetic fertilizer with compost will be quantified and compared to the mitigation potential of other recovery technologies of organic residues. Within this comparison the different soil enhancing properties of the compost will be considered. Oral (normal length)
Karin Gruhler Material and energy flow analyses of secondary building materials to reveal conflicts between environmental objectives  The German Resource Efficiency Programme "ProgRess” formulated the goals of decoupling resource consumption from economic growth, doubling raw material productivity by 2020, reducing the environmental impacts associated with the use of natural resources as far as possible and further developing and expanding the circular economy. In order to enable an almost circular economy in the construction sector, demolition materials must be recyclable and available with a certain consistency in specific quantities. However, in terms of sustainability, energetic aspects may not be ignored. The aim of the present study was therefore to extend the quantity-oriented studies on resource conservation potentials to include energy considerations and to develop a synoptic approach by which important building products can be presented and compared in a synoptic way. Methodologically, a consistent framework has been developed allowing an equivalent analysis of ten construction product groups - concrete, bricks, sand-lime bricks, gypsum, flat glass, mineral insulation materials, plastic profiles, other plastics, petroleum-based insulation materials and construction timber. For each group, instructive examples were analysed in the form of characteristic process chains from the demolition material to the application alternative. These differentiated and detailed analyses provide statements on material and energy flows and thus basic information on possibilities and limits of recycling. The investigations have shown that recycling is generally associated with lower energy costs than the provision of primary materials. Recycling paths that deviate from this must be questioned very critically. Furthermore, differences between the construction product groups could be identified and named. In the case of plastics, the energy aspect plays a more decisive role. For mineral materials, recycling makes sense above all with regard to the mass aspect. However, the main result is a clear plea for more consistent recycling ‐ from the point of view of materials as well as energy and therefore climate. Oral (normal length)
Mohammed Mazen HARIRI Preliminary Assessment for Main Processes of Circular Economy by multi-criteria methods  Production Processes Modifications are required to comply with generating new economic model. The transition to the circularity urges for developing Preliminary Preventive Tools and Techniques that keeps qualitative, safe and sustainable operability and functionality. Multi-criteria were required as a preventive tool to assess complex and dissimilar processes. To respond to the limitations of implementation of sufficient approach and the absence of detailed methodologies practically, this tool were developed by integrating Preliminary Risk Assessment PRA, Life Cycle Assessment LCA, Processes Efficiency PE, Hazard and Operability studies HAZOP, ISO Series, Tool for the Reduction and Assessment of Chemical and other environmental Impacts TRACI. The tool have been used to conduct the inventory and comparison between linear, circular and many circular production processes. To assess recycling rate in end-of-life products of 15 elements of periodic table locally. Also, to evaluate the behavioral changes of the materials which flow through this circularity. Risk Matrixes were developed and six critical points were appeared throughout processes. Radar graphs have been drawn according to the potential impacts: human direct, long-term, life support and nature direct, relevant pathways and receptors. The deficiencies included first and last Km, appearance of Volatile Organic Compounds VOCs, Emerging Organic Compounds EOCs and byproducts , functionality of second life recycled products and materials. To avoid critical impacts of the transition to circular economy fully without effective and safe technologies there is a need to use Hybrid economy for temporal period, to develop processes efficiencies, to control materials traceability , and to focus on second life properties of recycled materials. Oral (normal length)
Vincent Linderhof The role of biomass in a low-carbon and resource efficient Netherlands. Playing the game  Half of the renewable energy in The Netherlands is currently generated from biomass. One third of this biomass is organic waste. According to forecasts, biomass will continue to be an important source of renewable energy towards 2035. Biomass for energy is heavily disputed for several reasons: 1. Sustainability: trade-offs to land, landscape, water, biodiversity, soil. 2. Reduction of CO2 emissions doubtful. 3. Competition with growing food and feed. 4. Conflict with bio-based economy and cascade principle. 5. Conflict with circular economy, waste reduction and resource efficiency. These contrasting interests are the core of a serious game that simulates different pathways for production and use of biomass in the Netherlands between 2020 and 2050, and effects on land use, water use, agriculture, energy production and use, and emissions of greenhouse gases and nutrients. In this workshop the participants will play the game. The player can choose policy cards, see what complex reactions and trade-offs are generated and how the system changes towards or away from policy goals. The game creates insight into the connections between components of the system. The game is meant to be used for education and facilitating discussions between representatives of different disciplines and policy departments to create a better understanding for each other’s interests and viewpoints. It can also stimulate the creation of new interdisciplinary solutions. After the game we will discuss the role of sustainable biomass in the Dutch energy mix and the usefulness of the game to facilitate this discussion. Oral (normal length)
Anne Geißler Investigation of agricultural residues for the production of biofuel and for the use of nutrient recovery  Bioeconomics with the goal of achieving a biobased economy is a strategy of the Federal Government, which, however, has to be placed in a worldwide context due to globalization and climate goals. In the year 2030, the percentage of renewable energies in electricity in Germany should be 65 %. In addition to the avoidance of greenhouse gas emissions, carbon sequestration will also be addressed. New concepts for the use of agricultural residues are to be investigated, which on the one hand produce biofuels and recover nutrients with the help of carbonisation. These products can thus be used more specifically for fertilisation and substitute mineral fertilisers. Agricultural residues and by-products have with 17.6 million tons per year the highest unused technical potential in Germany, 8.5 million tons of this is cereal straw (Brosowski et al. 2015) This concept thus addresses the issues of closed circular economy, biofuels and sustainable agriculture which is directly linked to the conservation of the resource water. tasks: - Literature review - to do a comprehensive biomass analysis - preparation of an overview of biomass potentials for various recycling technologies (excisting and future technologies) - valuation of biochar as biofuel and the material flows of the processes - production of Biochar is a multifunctional material, caused by its high inner surface - Investigation of adsorption and desorption of nutrients such as potassium, nitrogen and phosphorus on biochar Based on the carbonization experiments, the biogas technology and its future viability will also be examined and compared with the carbonization concepts under consideration. Oral (normal length)
Lukas Gast Assessing end-of-life material flows of onshore wind turbines  Approximately 12,000 onshore wind turbines will reach their expected end-of-life (EOL) in the years following 2020 in Germany, which will lead to more than 1,600 decommissioned turbines per year (Deutsche WindGuard, 2016). This gives rise to challenges of material management of wind turbines including decommissioning, recycling and reuse. Current recycling strategies focus on a few specific components (e.g. rotary blades) and challenges associated with them. Although there are opportunities for reusing and recycling other components, there are no system-level studies yet which investigate the potential of reusing these other components and include the energy requirements for recycling. However, a better assessment of current and best practice material flows of wind turbines in their entirety could help to reduce their environmental impact. This talk provides a review of life-cycle assessments of 2 MW onshore wind turbines and provides an estimate of the circularity of selected turbines. The circularity index proposed by Cullen (2017), which includes material recycling rates as well as the energy demand for recycling, is used for assessing the circularity of selected wind turbines. In addition, different strategies are explored to increase the circularity of wind turbine material flows, in particular through improving material recovery and reusing components. These changes are visualised in Sankey diagrams for a selected turbine. The analysis highlights the gap between current practice and theoretically best practice at EOL and sheds light on the opportunities for diverting material flows at EOL. The results suggest that wind turbine material flows are currently far away from circularity but opportunities exist for improving reuse and recycling of components. Implementing these strategies could lead to major energy and hence GHG emissions savings. Overall, the circularity index and visualisation tools could be by policymakers and companies to monitor material flows and recycling strategies to address the challenges of EOL management. Oral (normal length)