Sharing Costs and Benefits in Urban-Industrial Symbiosis: Cross-Sectoral Impacts of Recycling Urban Waste Incineration Ash in Construction
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Date
2026
Publication Type
Conference Paper
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yes
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Abstract
Urban-industrial symbiosis (U-IS) supports Circular Economy (CE) goals by transforming urban waste into valuable resources. U-IS can be initiated either top-down, driven by policymakers, or bottom-up, when industries collaborate to share benefits and costs. In Europe, U-IS between cities and waste-to-energy plants has a long-standing tradition in energy recovery. However, ashes, being incineration residues are often landfilled. The European research project ‘Ashcycle’ has shown that sewage sludge and municipal solid waste incineration ashes can be used as supplementary cementitious materials, in alkali-activated materials, and in clay bricks—contributing to decarbonizing the construction sector. U-IS can also extend to other sectors. For example, phosphorus recovered from sewage sludge ash can benefit agriculture by enhancing domestic supply of fertilizers, while reducing reliance on vulnerable international supply chains. Similarly, extracting ferrous and non-ferrous metals (e.g., copper, zinc) can support domestic supply for the electronics industry. This study combines life cycle assessment (LCA) and cost-benefit analysis (CBA) to evaluate the environmental and economic impacts of U-IS across sectors. Using multi-objective supply chain optimization, we compare a U-IS scenario with a baseline where ashes are landfilled and conventional materials (e.g., Portland cement, conventional fertilizers) are produced. Findings reveal that U-IS can reduce CO2-eq. emissions by up to 80% and costs by nearly 50% at the regional level. While all industries benefit environmentally, cost impacts vary. For example, the cement and concrete sector could cut costs by 20% through ash recycling, while recovering critical raw materials may incur higher costs due to investments in the pretreatment technologies. Considering estimated regional benefits and CO2-eq. emissions reductions of U-IS, findings of this study can offer valuable insights for policymakers to apply targeted incentives and regulatory frameworks to foster U-IS implementation, thereby advancing the goals of a CE.
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published
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Book title
Proceedings of the 2nd International Conference on Net-Zero Built Environment
Journal / series
Volume
873
Pages / Article No.
1126 - 1132
Publisher
Springer
Event
2nd International Conference on Net-Zero Built Environment: Innovations in Materials, Structures, and Management Practices (Net-Zero Future 2025)
Edition / version
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Date collected
Date created
Subject
Urban-industrial symbiosis; Incineration ashes; Supply chain networks; LCA; Cost-benefit analysis
Organisational unit
03972 - Habert, Guillaume / Habert, Guillaume
02655 - Netzwerk Stadt u. Landschaft ARCH u BAUG / Network City and Landscape ARCH and BAUG