Construction and demolition waste (C&DW) is the largest waste stream in the EU by weight, of which the mineral content forming the biggest fraction. Construction and demolition is defined as a priority area in the EU according to the Circular Economy Action Plan (EC 2015) for closing the loop, while the revised Waste Framework Directive (WFD 2008/98/EC, amended 2018/851) sets a mandatory target for its recovery of 70 per cent by 2020. The recycling potential of C&DW, although high in quantitative terms, is still under-exploited. The mineral fraction of C&DW, for example, is currently mainly being used in road foundations or backfilled. The recovery performances, although high, differ significantly between EU Member States, varying in 2016 between 54 and 100 per cent (Eurostat, 2019), However, data on C&DW are currently not sufficiently robust; for instance, Member States have differing understanding and accounting systems for recovery operations of backfilling according to a European Commission study on C&DW management (Bio by Deloitte, 2017).
It is increasingly recognized that climate change due to anthropogenic greenhouse gas (GHG) emissions is one of the greatest challenges facing our society, with major implications for both human and natural systems. The built environment is responsible for a significant share of these emissions, for both the production and operation of buildings. In response, diverse initiatives are being developed and implemented at the local, national and international levels to limit the release of GHGs into the atmosphere. These initiatives rely on the assessment, monitoring, reporting and verification of GHG emissions and removals. To ensure that actions are effective at mitigating climate change, the annual accounting of GHG flows associated with buildings should be done in a lifecycle perspective. In other words, the analysis should consider all inputs (e.g. energy, materials) and outputs (e.g. emissions, waste, co-products) for each lifecycle stage including production, operation and end-of-life.
Selective demolition. The tool to enable reuse and high-quality waste for recycling
Valuable raw materials are available within demolition wastes. The actual characteristics of those stocks depend on the demolition process producing those wastes. And, as such, it is also determining the feasibility and economics of the recovery of those raw materials.
The overall aim of selective demolition, based on information from the pre-demolition audit, is to recover high-quality (pure) material fractions for recycling or reuse. The purpose of such an audit is to identify hazardous materials that have to be removed prior to demolition and assess the recycling potential. The selective demolition is followed by the processing of the material fractions to ensure high-quality recovery. Selective demolition does not reduce the total amount of waste generated but enables the recovery of fractions for high-quality recycling. Selective demolition is closely linked to waste sorting requirements.
There are various boundary conditions, often case specific, affecting selective demolition. Economic factors are the most important, both promoting and hampering the use of selective demolition. Selective demolition results in materials with a higher value. For example, instead of a mixed stony fraction, a pure high-grade concrete fraction can be recovered. Furthermore, the amount of rejects for landfilling can be minimized.
Odysseus & Athena Institute aims to identify and prioritize existing technical and non-technical gaps in current practices for smart demolition of buildings in Greece and collect real data with European perspective which will allow to define and harmonize current existing needs constituting the basis for the development of novel procedures, guidelines, smart tools and policy recommendations. For this purpose will work together with technical departments of 10 Greek municipalities from different regions.
As a second phase ODENA Institute plans to develop o BIM-based software tool and a tracking system that will contribute to cost-effective and highly efficient demolition.
