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Keywords Waste, Recycling, Risk management, United Kingdom, Construction industry
Abstract In England and Wales, the construction industry produces 53.5 Mt of construction and demolition waste (C&D waste) annually, of which 51 percent goes to landfill, 40 percent is used for land reclamation and only 9 percent is crushed for future use or directly recovered C&D waste may be contaminated, either through spillage from industrial processes or contact with contaminated land. There are no guidelines on how to classify C&D waste as contaminated or on risk management for contaminated C&D waste. Research at the UK Building Research Establishment and the University of Manchester has shown that new taxes are making disposal of C&D waste to landfill uneconomic, that low grade "land-modelling" recycling is increasing, and that disposal on-site is preferred. Sampling spatially of structures before demolition and temporally of processed C&D waste emerging from crushers is enabling sources of contamination and exceedance of guideline values to be compared with natural background levels. Improved sampling procedures and recommendations for risk assessment for the re-use of C&D waste are being prepared.
Introduction
Construction and demolition (C&D) waste is increasingly being seen as a valuable source of engineering materials for the construction industry in the UK. Using C&D wastes potentially reduces reliance on primary aggregates and lowers the environmental impact of construction. The Environment Agency (England and Wales) estimates that the construction industry currently produces approximately 53.5 million tonnes of construction and demolition waste annually (Bell, 1997). At present C&D waste is disposed of as follows:
* 27.4 million tonnes (51.2 percent) are disposed direct to landfill;
* 21.2 million tonnes (39.6 percent) are exempt from licensed disposal and are primarily used for land modelling during the construction projects;
* 5 million tonnes (9.2 percent) are either crushed to produce a graded product or directly recovered.
The 1995 UK Government White Paper Making Waste Work (DoE, 1996) had targets for increasing the use of waste and recycled materials as aggregates to 30 million tonnes per year by 2006. The UK Consultation Paper on sustainable construction Opportunities for Change (DETR, 1998) highlights the need for incentives to encourage the use of recycled material and acknowledges the importance of economic considerations. It also recognises constraints linked to the quality...