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Monday, November 18, 2019

Construction waste





Construction activities can generate large amounts of waste materials that then need to be disposed of. In addition, at the end of a building's life, it may be deconstructed or demolished, generating significant amounts of waste. Construction waste includes the waste that is generated during construction activities (such as packaging, or the products of demolition) and materials that are surplus to requirements (as a result of over-ordering or inaccurate estimating).

Typical construction waste products can include:

Insulation and asbestos materials.
Concrete, bricks, tiles and ceramics.
Wood, glass and plastic.
Bituminous mixtures, coal tar and tar.
Metallic waste (including cables and pipes).
Soil, contaminated soil, stones and dredging spoil.
Gypsum.
Cement.
Paints and varnishes.
Adhesives and sealants.
Increasingly, there are options available in terms of reusing and recycling materials, and reducing the amount of waste produced in the first place, but despite this, a large amount of construction waste is still disposed of in a landfill. 32% of landfill waste comes from the construction and demolition of buildings and 13% of products delivered to construction sites are sent directly to the landfill without having being used (ref. Technology Strategy Board)

This can be an expensive process, as the 1996 Finance Act introduced a tax on waste disposal on all landfill sites registered in the UK. 
To help tackle this, a site waste management plan (SWMP) can be prepared before construction begins, describing how materials will be managed efficiently and disposed of legally during the construction of the works, and explaining how the re-use and recycling of materials will be maximised. For more information, see Site waste management plan.

It may be possible to eliminate a certain amount of construction waste through careful planning. For example, steel formwork systems might be capable of being used for concrete works which can then be reused elsewhere on the project/s in place of timber formwork which is classed as waste once it has been used.

Other types of construction waste may be capable of being minimised; for example, products which are provided with reduced packaging or those which are composed of recycled materials. There can also be opportunities to re-use materials and products which are in a suitable condition (e.g. doors, windows, roof tiles and so on), or exchange them for other materials with a different construction site.

Materials and products which cannot be eliminated, minimised or reused may have to be disposed of as waste. Before sending waste for disposal, it should be sorted and classified to allow waste contractors to manage it effectively and ensure that hazardous waste is properly handled.
The Problem
Disposal of public fill at public filling areas and mixed construction waste at sorting facilities or landfills has been the major approach for construction waste management. For sustainable development, we can no longer rely solely on reclamation to accept most of the inert construction waste. As such, the government is examining ways to reduce and also to promote the reuse and recycling of construction waste. Nevertheless, there will still be a substantial amount of materials that require disposal, either at public fill reception facilities or at landfills.
Today, we are running out of both reclamation sites and landfill space. With the current trend, our landfills will be full in mid to late-2010s, and public fill capacity will be depleted in the near future. In 2013, the mixed construction waste accounts for about 25% of the total waste intake at the three existing landfills. If there are insufficient public fill capacity and waste reduction measures being implemented, more public fill would probably be diverted to landfills and the landfill life will be further shortened.



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