Of the large amounts of solid waste produced in the UK, a significant proportion is disposed of in landfill sites which, in some areas of the country, are in critically short supply. It is estimated that perhaps half of this landfilled waste is produced by the construction and demolition industries in which the majority of civil engineers are engaged.
Civil engineers are also responsible for municipal functions such as treatment and disposal of all wastes. The Institution supports the approach outlined in the waste management hierarchy, which prioritises elimination and prevention of waste over minimisation, re-use, recycling, recovery, treatment and disposal.
Construction and demolition waste
The management of construction and demolition waste should aim to conserve landfill capacity, reduce the environmental impact of new projects and reduce demands for primary materials.
Waste minimisation techniques are well established for scarce and valuable materials such as copper pipe and should be developed for other materials and processes. Civil engineers should aim to minimise waste arisings at all stages of a project, from design to effective site management, operation, maintenance and decommissioning. In doing so, they will need to consider the scope for using existing recovered materials and to evaluate the whole life costs of different designs.
Segregation of waste should be encouraged to identify materials which can be re-used or recycled, and to reduce cross-contamination of waste streams. The latter often results in disposal which would otherwise be unnecessary. Segregation also allows for analysis of waste produced, from which opportunities for further minimisation can be developed.
Many construction wastes are classified as such due to their location, time of arising or low value relative to the cost of processing. Specifications should be developed or modified where possible to encourage use of suitable recovered materials in low risk applications.
Treatment and disposal methods
In the long term, an integrated approach to materials supply, management and disposal is needed, in which the environmental and energy costs of all options are objectively assessed.
However, landfill will remain the best practicable environmental option in many cases and the UK's expertise in landfill technology should be developed further.
Sensitive use of materials in restoration can help to improve some blighted landscapes. However, opportunities to do so are becoming increasingly rare, and should not be used to justify landfilling of high value materials.
Other disposal and treatment methods, such as composting and incineration with energy recovery, have a vital role in the waste management hierarchy and should be actively encouraged where practicable. However, their full environmental impacts must be considered; for example, recycling can use energy and produce pollution, and requires the development of markets for its products.
Opportunities for extracting energy from waste should, as a matter of principle, be sought for all waste disposal methods. The Institution supports the need for greater research efforts in this area.
National and local waste management strategies
Fiscal and other measures to reduce waste should be supported, and development of more sustainable waste management processes encouraged. A greater proportion of Landfill Tax revenue should be reinvested in such developments. The waste management industry should be encouraged to support approved environmental bodies, taking advantage of tax credits available under the Landfill Tax regime.
The introduction of a primary materials tax would help to minimise construction wastes.
Local authorities have a duty to seek improvements in the management of household and commercial waste arisings. Recent proposals for county and district authorities to collaborate in producing statutory Local Waste Management Strategies are a positive development.
Waste Management Strategies should encourage innovative schemes for collection, sorting, re-use and final disposal of waste arisings, and development of markets for recycled materials, in order to minimise the amount going to landfill.