By Mahmoud Alhawamdeh
Image by iStock
Defining and classifying the types of Construction and Demolition Waste (CDW) and specifying the domain of its different management methods, is essential in achieving accurate quantification of generated waste volumes as well as in determining the scope of application of reuse and recycling targets and their calculation rules.
Therefore, lack of clarity on the concepts and management aspects of CDW persist as a major challenge to its adequate management. As a fundamental part of RECONMATIC project, it is imperative to gain a clear practical insight on CDW concepts and domain of the different waste treatment operations, which will assist with planning and decision-making.
What is construction and demolition waste (CDW)?
In a general way, CDW is waste that results from construction and demolition, renovation or reconstruction activities of buildings and infrastructure. It is a combination of various materials, containing inert and non-inert waste as well as hazardous and non-hazardous waste.
CDW often contain:
• Concrete, cement, bricks, tiles, ceramics and Gypsum
• Wood, glass and plastic
• Metallic waste, including cable
• Soil, contaminated soil, stones and dredging spoil
• Bituminous mixtures, coal tar and tar
• Adhesives and sealants
• Paints and varnishes
• Insulation and asbestos materials
What is construction and demolition waste (CDW) management?
CDW accounts for approximately a third of all waste generated in the EU, which equates to 450 – 500 million tonnes generated annually. Putting wasted materials in the correct bin is not enough to fix the tonnes of CDW the EU produce each year, and that’s why creating a waste management plan for municipalities and businesses is necessary to understand the different option and solutions for managing CDW.
These management plans aim to minimise the volumes of waste that is produced by the construction sector through managing and monitoring how materials will be used, and how waste will be collected, transported, recovered, disposed and the after-care of disposal sites.
Waste hierarchy (Image by Waste Framework Directive/European Commission)
Prevention
We know it’s easier said than done but minimising the quantities of material that ends up being thrown away is the first step to correctly manage waste generation during construction and renovation activities.
This could include correct quantity estimation and ordering of materials, and making sure that tasks are correctly done to avoid redoing them which could result in waste generation as well as ordering more materials that could ultimately become further waste.
Prepare for re-use
Prepare for reuse is not the same as ‘reuse’, even though both terms are sometimes used synonymously by people. Checking, cleaning or repairing operations is performed in either case. However, precondition for ‘preparing for reuse’ is that the respective item was waste, whereas ‘reuse’ happens when there is no compromising of quality and safety of products/materials (unused materials).
Prepare for reuse of CDW on future projects can be an effective method to minimise overall wastage and may even present new opportunities to create a new use for them. Understanding what types of waste can be reused or recycled is an important step towards discovering the many opportunities they present.
Recycling
Recycling involves reprocessing waste into products, materials or substances whether for the original or other purposes. Almost all types of CDW can be recycled into secondary materials, however, there are misperceptions about what can be considered as recycling operations, such as energy recovery or backfilling operations.
Being aware of the correct way to recycle waste can greatly minimise the quantities of CDW that is sent to landfills which in turn can minimise the impact that they have on our environment.
Recovery
This includes other recovery operations than prepare for reuse and recycling in which waste serving a useful purpose, including energy recovery and the reprocessing into materials that are to be used as fuels.
Disposal
Waste disposal is the end of pipe solution in the waste management hierarchy and only considered once all other possibilities have been explored, due to its negative impact on the environment. Disposing CDW left after any waste treatment process (residual waste) to landfills is considered as the most common disposal method. Other methods can include land treatment and Incineration.
It is important to be aware of the protocols that certain types of CDW require in order to be disposed of correctly, such as paint, asbestos and other hazardous materials.
Why is it important to understand the concepts of construction and demolition waste (CDW) management?
Knowing the definition and concepts of CDW and its associated treatment operations creates the basis for achieving proper waste management, which in turn helps in the effective formulation of policies and the application of regulatory controls to protect the environment.
Terms and concepts in CDW management throughout projects’ lifecycle processes (Image by Author)
Uncertainty about what is considered as CDW, and ambiguity around the scope of waste management methods lead to discrepancies of reporting CDW statistics to local municipalities and relevant concerned bodies. For example, uncertainty about the inclusion of naturally occurring soil and stones, generated during construction activities, is a common source of inconstancy in national CDW statistics. Also, in many cases waste collected is reported as waste recycled despite the significant material loss between these two phases.
As the aim of RECONMATIC project is to develop an innovative solutions and tools for waste management in the EU throughout construction projects’ lifecycle, it is important to deepening the understanding of CDW concepts, definitions, and types of quantities; distinguishing between the different CDW treatment operations and associated output volumes; and improving CDW reporting mechanisms.