Waste management and recycling offer major benefits in transport infrastructure

Guidance on recycling in transport infrastructure is provided in a new document produced by TRL Limited. Much has been achieved to remove obstacles to recycling, but some issues still need to be addressed. Dr Murray Reid of TRL Limited reviews progress on the road to recycling

Use of recycled asphalt as sub-base in renewal works on A14 trunk road at Milton, Cambridgeshire

Use of recycled asphalt as sub-base in renewal works on A14 trunk road at Milton, Cambridgeshire

As the modern world comes to terms with the fact that the planet's resources are finite, the pressure to increase recycling is affecting all sectors of the construction and waste management industry. In many areas this requires a considerable readjustment in attitudes. In the construction and maintenance of transport infrastructure, as in many other branches of construction, there has in the past been a reliance on using only high quality natural aggregates, and sending any marginal or unfamiliar material to landfill. Transport infrastructure includes the earthworks, pavements and drainage required for roads, railways, airports and canals.

These powerful drivers have resulted in an increase in the use of alternative materials and in the development of in-situ recycling techniques. However, in some areas progress has been slow because of real or perceived problems with the application of these materials and techniques. Reasons often given for failure to use recycling include a lack of specifications for the materials and techniques, lack of appropriate test methods, concern about quality control and variability of the materials and methods and difficulty in ensuring an adequate supply of material.

Waste classification
The waste management licensing regulations are often seen as a barrier, as it is not clear whether alternative materials are classed as waste, and, if so, whether they are covered by exemptions. Contractors are very reluctant to take on the burden of a waste management licence, and the timescale required to resolve these issues often precludes the use of these materials in construction contracts. In some cases, the environmental regulators may be concerned about the use of certain materials in terms of dust or gaseous emissions or contamination of surface and ground waters.

Operators of recycling centres often experience difficulty in obtaining planning permission and other approvals and adversarial conditions of contract can inhibit the use of innovative recycling techniques. Overall, there is a lack of awareness of the possibilities of recycling, coupled with a strong awareness of potential problems.

To help overcome these problems and increase the amount of recycling in transport infrastructure, TRL Limited (formerly known as the Transport Research Laboratory) carried out a research project funded by DTI and the former DETR under the Partners in Innovation programme. Lafarge Aggregates UK and the Hanson Environment Fund, through landfill tax credits, provided additional funds. A steering group with cross-industry experts supported the project team and ensured that all the important issues were covered. The main output from the project is a guidance document, entitled *Recycling in transport infrastructure. The document is targeted at managers and technical personnel in the main stakeholder groups, including local authorities, contractors, designers, producers of secondary/recycled materials, environmental regulators, owners and operators of transport infrastructure.

Guidance content
The document consists of three parts. In Part 1 the main issues affecting recycling in transport infrastructure are identified and discussed. Part 2 contains available guidance on these issues. Because different stakeholders can have different views on the same topic, sub-sections of the text have been prepared for each stakeholder group. Some issues require further action: these are summarised in Part 3 in tabular form for each stakeholder group.

The actions are ranked in terms of relative priority, timescale and nature. Fourteen case studies are presented in an appendix to illustrate how greater recycling can be achieved in a range of situations, and how common problems can be overcome.

The project revealed that guidance is available for many of the issues that were raised as potential obstacles to recycling. In recent years a number of specifications have been developed to cover many of the materials and techniques that are now available.

There have also been major improvements in quality control procedures. Materials produced under a quality control plan should be at least as fit for purpose as natural aggregates. Guidance was published by the then DETR on controlling the environmental effects of recycled and secondary aggregates production. This will benefit planning authorities and the owners and operators of recycling centres.

Examples of the use of partnering and global costing by organisations, such as the British Airports Authority, illustrate the economic and environmental benefits that these approaches can bring A number of the case studies describe the successful use of particular materials and techniques.

The current waste management licensing and exemption process, as it applies to recycling in transport infrastructure, is described, and regional variations in Scotland, Wales and Northern Ireland are given.

Difficulties remain
The available guidance indicates that recycling can be successfully carried out, and local authorities have often been to the fore in taking new techniques forward. Some areas of difficulty remain, particularly connected with the application of the waste management licensing regime. This is acting as a significant restraint on the use of alternative materials in construction projects, where the short timescale of the projects means it is often impossible to resolve issues with the environmental regulators in sufficient time to enable the materials to be used in the contract. Variation in interpretation of the regulations between different offices of the environmental regulators is often cited as another reason for not using recycling. In return, the environmental regulators point out that contractors often submit applications at extremely short notice, often without sufficient information to enable them to make a decision. The Environment Agency has a process handbook for processing waste management licensing applications, which should ensure uniform treatment of applications throughout the country. They also point out that the licensing process has statutory consultation periods of 28 days built into it, and that contractors should allow a reasonable time for this process.

Clearly, the waste management issues need to be streamlined if the full potential for recycling is to be realised. The Environment Agency launched a construction campaign in March 2001 to improve the environmental performance of construction sites and to engage in more liaison and training with industry. In time this may bear fruit with a greater understanding by each side of the other's position and a more constructive dialogue. Another idea that arose out of the TRL project is to establish a National Industrial Forum where environmental regulators, industry, infrastructure owners and operators and government could meet to discuss problems such as these and agree ways to move forward. The idea arose out of the constructive, but often vigorous, debates in the steering group over the course of the project, which were very helpful in clarifying what the real issues were and identifying ways to deal with them. Anyone with views on this topic is invited to contact the author.

In the areas where progress has been made, it is because the stakeholders involved have acted to address the problems, for example in the preparation of specifications and design guides for new materials and methods. This has often involved commissioning research to obtain the necessary data on which to base the specifications. Where a number of stakeholders have acted in concert the results have been particularly effective. A good example is the production of a quality control document for recycled aggregates by a working group involving BRE, the then DETR, the Highways Agency, local authorities (via CSS), the Quarry Products Association and a number of aggregate producers and consultants. A similar approach will be required to overcome the remaining obstacles to recycling.

*The guidance document "Recycling in transport infrastructure" is available from TRL Publications, Tel. 01344 770783 or by email at info@trl.co.uk. For further information on technical aspects, contact Dr Murray Reid, TRL Limited, Tel. 01344 770283, email jreid@trl.co.uk.


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