Construction and Demolition Waste (C&DW) consists of numerous types of materials, including but not limited to concrete, bricks, gypsum, wood, glass, metals and plastic, all valuable resources for the economy. There is a high... [ view full abstract ]
Construction and Demolition Waste (C&DW) consists of numerous types of materials, including but not limited to concrete, bricks, gypsum, wood, glass, metals and plastic, all valuable resources for the economy. There is a high potential for recycling and re-use of C&DW, since some of its components have a high resource value, giving as a result a potential reduction of landfill space requirements and conservation of natural aggregate resources. Most of the environmental policies aim to increase C&DW recycling, as in the Directive 2008/98/EC on waste, which stresses the need to improve C&DW management in the European Union to 70% of reuse, recycling and material recovery by 2020.
In order to evaluate the potential of materials contained in C&DW to be recovered for recycling, a conceptual framework is developed in this work in which the performance of two recycling facilities (basic and advance) with different technological levels is analysed.
The basic C&DW recycling plant operates with limited overall capacity and simple separation technology. This type of recycling plant is focused on diverting the non-petrous fraction from the main stream, trying to crush only the larger fraction. The reinforced concrete is treated manually; this does not allow to recover all the materials contained in them (steel and concrete). The advanced plant has more complex technology based on different batches (diverted and mixed) are treated separately giving as a result high quality aggregates.
In Cantabria (Spain), C&DW arriving at recycling plants is mostly mixed waste (nearly 85%). This implies that more effort is necessary to treat it to obtain recycled aggregates with an adequate quality. The study starts with the definition of the input stream and the description of the equipment included in both type of recycling facility. Besides, different scenarios are proposed in this work to simulate different composition of input waste and to study the influence of the composition and type of plant on the quality of the final products and recycling target.
Secondly, the inclusion of a mass balance approach based on input-output analysis of the entire system is done in order to estimate the type of output material generated at each plant. As four scenarios are considered and two plants are analyzed abundant information is obtained and it can be observed that more output streams are generated for advance recycling plant compared basic recycling facility. These additional output streams allow improving the quality of the recycled aggregates giving the chance to use them in upgrade applications.
Finally, it is also analysed whether the target of 70% recycling of C&DW by 2020 can be achieved with the current management practices and with the other scenarios presented in this work. The results show that the basic plants obtain moderate (50%) recycling percentages; however, the advance plants can obtain high percentages (until 85%) in some of the scenarios proposed.
Development of design and modelling methods , Processing possibilities and logistics
