Periodic Reporting for period 2 - AshCycle (Integration of Underutilized Ashes into Material Cycles by Industry-Urban Symbiosis)
Okres sprawozdawczy: 2023-12-01 do 2025-05-31
The AshCycle project provides tools for reducing the waste generation from the incineration of municipal solid waste, biomass, and sewage sludge by developing resource recovery and new utilization possibilities for the mineral residue. Currently, the ashes resulting from these processes are underutilized and largely landfilled or used in low-value applications . This leads to significant losses of metals, nutrients, rare earth elements, and industrially valuable minerals that are present in the ashes on the EU level. Moreover, the cost of ash landfilling is expected to increase in future due to the waste taxes or disposal fee, difficulties in acquiring new landfill sites, and stricter EU landfill directives.
The AshCycle project will deploy the Industrial-Urban Symbiosis (I-US) concept by demonstrating novel recovery methods for valuable elements from the ashes. Furthermore, the aluminosilicate-rich minerals recovered from the ashes are piloted as a feedstock for construction and wastewater treatment materials leading to increased resource efficiency and circularity. Thus, the flows of energy, waste, and water intercept in the AshCycle concept facilitating their circularization. To fully realize the I-US concept, also the engagement of citizens, civil society and end users are addressed in the project.
The overall objective of AshCycle is to develop and demonstrate regional I-US concepts for utilization of incineration residues by extracting metals, nutrients, rare earth elements coupled with using the mineral residues as secondary resources in construction and wastewater treatment products. The demonstrations are implemented by regional real-scale pilots, virtual or bench-scale replication cases, and digital tools indicating the wider replication potential. The main objectives of the AshCycle project are: (1) to develop a software for ash producers to evaluate the utilization potential ; (2) to decrease waste generation and to decrease CO2 emissions; (3) to demonstrate material recovery technologies and ash-based products; and (4) to address the safety and sustainability performance of the products and technologies.
The AshCycle project will deploy the Industrial-Urban Symbiosis (I-US) concept by demonstrating novel recovery methods for valuable elements from the ashes. Furthermore, the aluminosilicate-rich minerals recovered from the ashes are piloted as a feedstock for construction and wastewater treatment materials leading to increased resource efficiency and circularity. Thus, the flows of energy, waste, and water intercept in the AshCycle concept facilitating their circularization. To fully realize the I-US concept, also the engagement of citizens, civil society and end users are addressed in the project.
The overall objective of AshCycle is to develop and demonstrate regional I-US concepts for utilization of incineration residues by extracting metals, nutrients, rare earth elements coupled with using the mineral residues as secondary resources in construction and wastewater treatment products. The demonstrations are implemented by regional real-scale pilots, virtual or bench-scale replication cases, and digital tools indicating the wider replication potential. The main objectives of the AshCycle project are: (1) to develop a software for ash producers to evaluate the utilization potential ; (2) to decrease waste generation and to decrease CO2 emissions; (3) to demonstrate material recovery technologies and ash-based products; and (4) to address the safety and sustainability performance of the products and technologies.
The I-US model and indicators were finalized, including an optimization model comparing centralized and decentralized ash supply chains, and creating a sustainability indicator framework. The model has been applied to pilot regions through interviews and data collection to evaluate the costs, benefits, and business cases for I-US. A digital LCA-GIS tool has also been created to assess environmental and economic impacts using different I-US models, incorporating spatial data and ongoing updates with real pilot data. Lastly, the final version of Ash Modeling Application (AMA) software, developed by AI4Value, is now deployed and in maintenance phase. This software allows LCA optimization and matching ash characteristics to application requirements. AMA remains available for project partners until end of the project.
75 ash samples have been collected and characterized. This data provides crucial information for resource recovery potential and product development. The ash pretreatment method using sodium hydroxide effectively mitigates expansion and cracking caused by metallic aluminum. Carbon sequestration capacity has been assessed. Results showed that fly ashes generally have higher sequestration potential than bottom ashes, though actual CO2 uptake varies with curing conditions, highlighting the need for further optimization.
A literature review was prepared, focusing on phosphorus and metals recovery from ashes. Waste-acid extraction and electrochemical techniques were identified as feasible approaches. A pilot-scale electrodialytic separation (EDS) cell system was successfully developed. EDS experiments conducted by DTU demonstrated successful extraction of heavy metals and rare earth elements (REEs) from various ashes, achieving over 75% extraction for metals like Cd, Cu, Zn, and Pb under optimized conditions, and over 90% for certain REEs in stirred set-ups. Metal recovery from EDS-treated solutions using reduction crystallization and electrowinning methods was studied. Ash-based adsorbents developed showed preliminarily promising results for removing phosphate and ammonium from water. Finally, the safe removal of hazardous elements like Ni, Cd, and As that cannot be economically recovered was assessed, with precipitation at varying pH being tested and MgO-functionalized geopolymers considered for enhanced immobilization.
The mix designs for using ashes as supplementary cementitious materials in Portland cement concrete, alkali-activated concrete binders, carbstone products, fired or unfired clay bricks, and granulated ashes for earth construction have been optimized. The optimized mix designs met structural and durability standards, and thus are ready for the semi-industrial trials and pilots.
8 out of 11 large-scale pilots have been completed.
An overview of applicable legislation and standards for each application or product was collected. AshCycle partners advanced regulatory and environmental validation for ash-based construction products. ZAG and UNIZG led standardization efforts, leaching tests, and technical assessments for market approval.
75 ash samples have been collected and characterized. This data provides crucial information for resource recovery potential and product development. The ash pretreatment method using sodium hydroxide effectively mitigates expansion and cracking caused by metallic aluminum. Carbon sequestration capacity has been assessed. Results showed that fly ashes generally have higher sequestration potential than bottom ashes, though actual CO2 uptake varies with curing conditions, highlighting the need for further optimization.
A literature review was prepared, focusing on phosphorus and metals recovery from ashes. Waste-acid extraction and electrochemical techniques were identified as feasible approaches. A pilot-scale electrodialytic separation (EDS) cell system was successfully developed. EDS experiments conducted by DTU demonstrated successful extraction of heavy metals and rare earth elements (REEs) from various ashes, achieving over 75% extraction for metals like Cd, Cu, Zn, and Pb under optimized conditions, and over 90% for certain REEs in stirred set-ups. Metal recovery from EDS-treated solutions using reduction crystallization and electrowinning methods was studied. Ash-based adsorbents developed showed preliminarily promising results for removing phosphate and ammonium from water. Finally, the safe removal of hazardous elements like Ni, Cd, and As that cannot be economically recovered was assessed, with precipitation at varying pH being tested and MgO-functionalized geopolymers considered for enhanced immobilization.
The mix designs for using ashes as supplementary cementitious materials in Portland cement concrete, alkali-activated concrete binders, carbstone products, fired or unfired clay bricks, and granulated ashes for earth construction have been optimized. The optimized mix designs met structural and durability standards, and thus are ready for the semi-industrial trials and pilots.
8 out of 11 large-scale pilots have been completed.
An overview of applicable legislation and standards for each application or product was collected. AshCycle partners advanced regulatory and environmental validation for ash-based construction products. ZAG and UNIZG led standardization efforts, leaching tests, and technical assessments for market approval.
The Ash Modelling Application (AMA) combines feed ash characterization data to the software and then AI-based algorithm is used to interpret the most feasible applications for the ashes. Moreover, the software has in-built LCA and GIS capabilities which enables it to take also environmental sustainability and logistics into account. Once this software is fully functional (i.e. the AI-algorithms have been sufficiently trained with existing data about the correlations between ash characteristics and resulting properties in applications), it has potential to revolutionize the ash utilization.
For the use of sewage sludge ash in brick production, the research has moved beyond the current practice in literature, which is based somewhat on try-and-error, to a more thorough understanding of the fundamentals of what is happening at the chemical and micro-scale , e.g. investigating what is the influence from the clay type on the prick properties when using ash in the recipe.
The ash characterization data provides information about the quantities of REEs and other critical raw materials in ashes with a wide geographical distribution within the EU.
For the use of sewage sludge ash in brick production, the research has moved beyond the current practice in literature, which is based somewhat on try-and-error, to a more thorough understanding of the fundamentals of what is happening at the chemical and micro-scale , e.g. investigating what is the influence from the clay type on the prick properties when using ash in the recipe.
The ash characterization data provides information about the quantities of REEs and other critical raw materials in ashes with a wide geographical distribution within the EU.