Recycling measures and waste management in the construction industry

The EC Directive 751442 and Recommendation 811972 encourages Member States to introduce recycling measures largely in order to conserve the world's diminishing supply of resources. Recycling, however, is not only a matter of resource conservation: it is also a question of good waste management which could well save money by allowing a construction company to maximize the hidden potential within waste products. The hidden benefits of recycling may entail aggregate production, the re-extraction of metals, the re-burning of waste for energy (as in cement manufacture), and the rescue of components or products such as panel doors, windows and bricks.

Besides fossil-fuel energy, the primary mineral and natural resources employed in the UK construction industry are stone, sand, gravel, clay and timber. The main environmental impacts are in extraction (habitat loss, agricultural land take, landscape damage, methane release), in transportation (noise, dust, carbon dioxide emissions, air pollution) and in construction (energy use, noise, community disturbance). The production of a bag of cement highlights the problem. First, land is lost for the extraction of clay and chalk, large amounts of energy are

London Docklands Flats For Sale

Figure 25.3

Recycling buildings and giving them new uses is as important as recycling bottles. Warehouse conversion to apartments in London Docklands (Brian Edwards©.)

Figure 25.3

Recycling buildings and giving them new uses is as important as recycling bottles. Warehouse conversion to apartments in London Docklands (Brian Edwards©.)

used in the burning of materials to make cement (enough fossil-fuel energy to drive a family car for 80-100 miles), further energy is consumed and pollution created in transportation, and finally more energy is used in concrete making equipment on the building site. This cycle of landscape impact, energy use in manufacture and transportation is typical of building products from plasterboard to roofing tiles. Although the environmental impact of timber products is less acute, there are significant costs here too, especially with the application of timber preservatives, paints and solvents, and in transportation.

Measuring environmental impact is a complex business. There may be environmental benefits as well as losses, as with timber production and also mineral extraction where wildlife habitats are created around former gravel or clay pits. As a general rule, however, environmental impacts should be kept to a minimum and to allow this to happen the construction industry is encouraged by EC directives to adopt recycling measures.

The landfill tax introduced in the UK on 1 October 1996 has had the effect of focusing attention upon construction waste problems. Since the tax, skip hire has doubled and the cost of construction has risen by 1 per cent, but more importantly the tax burden has provided an incentive to recycle and reduce the volume of waste generated. Waste minimalization is effectively dealt with at both the design and construction stage. It is possible to reduce waste by designing and specifying materials with low wastage rates, using minimal packaging, maximizing the use of materials which can be reused (bricks and steel) and specifying materials made from waste created in other industries. Contractors have a duty of care towards the environment at the building site and need to ensure operatives follow contract clauses on waste minimalization.

The UK construction industry generates about 70 million tonnes of waste a year which is nearly a quarter of all waste. In Europe, 1.6 billion tonnes of waste are produced each year. Under EU law the producer has primary responsibility for waste reduction and this could be interpreted as embracing designers and those who specify materials. As a matter of course architects should employ those materials from a waste minimalization viewpoint.

Reuse Matter Material

Figure 25.4

Even when older buildings cannot be reused in their entirety, their construction elements should be recycled in other buildings.

Figure 25.4

Even when older buildings cannot be reused in their entirety, their construction elements should be recycled in other buildings.

Waste should be seen as a potential resource capable of reuse, recycling or being employed as a material within another product. Recently, new construction products have appeared on the market based upon recycled materials from other industries. These include wood alternatives based upon recycled tyres and plastic, flooring made from reconstituted wooden pallets, straw-based walling systems,combinations cf wood waste and cement to create insulating boards, aluminium roofing shingles made from recycled drink cans, recycled wool fibres from the clothing industry made into insulating felts, recycled paper-based insulation boards, and paints made from recycled household hazardous waste.

Recycled products reduce the demands made for new materials and components. The main construction materials capable of being recycled are:

  • aggregates produced from crushed concrete;
  • structural members such as steel girders, timber beams and joists and aluminium framing;
  • small components such as bricks, roofing tiles, slates and concrete blocks;
  • decorative elements such as sash windows, panelled doors, window shutters, architraves, etc.

Recycling has three main benefits: it reduces the demand upon new resources, it cuts down on transport and production energy costs, and it uses waste which would otherwise be lost to landfill sites. Construction in the UK generates about 40 million tonnes of carbon dioxide and lesser quantities of acid gas and nitrous oxide.' Recycling, though it will not prevent these adverse environmental impacts,

1 Environmental Issues in Construction CIR1A Special Publications No 94, 1993, p 55.

will at least reduce them. At the end of a structure's life, large quantities of waste material are produced, adding to the 70 million tonnes of construction waste per year. Although the UK construction industry recycles about 11 million tonnes of this, it is thought there is the potential for 70 per cent of all construction waste to be recycled2 A major impediment to recycling is the lack of foresight shown by designers in anticipating the reuse of structural members such as steel beams and smaller components such as bricks. Another impediment is the lack of facilities for recycling, especially for more dangerous construction substances. Recently, however ICI, ISC/Rhone Poulenc and Du Pont have offered a free recycling service for CFCs, and a few local authorities recycle CFC refrigerants. Those involved in specifying such materials could use clauses which facilitate easy dismantling and hence encourage recycling.

As discussed elsewhere in this book, eco-labelling has the potential to identify recycling possibilities. Once the ecological and environmental equations of a construction component or even a whole building have been identified, consumers and the professionals they employ will be able to consider recycled materials when new construction is in hand, and know how to reuse elements of a building when refurbishment or demolition are under consideration. The current lack of legislation to demand eco-labelling in the building industry has the effect of failing to bring energy costs, environmental costs and ecological impacts to public notice.

Other countries are more keen to recycle their construction waste than in the UK. This is party because countries such as Holland and Germany do not have Britain's aggregate or energy resources, and because of greater public awareness of the environmental benefits of recycling. In Germany plastics are readily recovered for reuse or reburnt in power stations for electricity production. Glass, steel, bricks and structural timber are also collected in Germany often through recycling schemes promoted by regional councils. In Britain, bricks are beginning to appear as a recycled material often in conjunction with house building where the patina of second-hand bricks has a particular appearance. It is thought that 2 per cent of brick consumption in the UK consists of recycled bricks, making a total of 75-100 million bricks per year from recovered sources.3

Recycled buildings

The benefits of recycling building materials apply equally well to the reuse of whole structures. The conservation of buildings not only saves resources and energy, but ensures

Economic Sectors

Figure 25.5

Conserving buildings creates many useful jobs and helps promote heritage-led tourism, one of Europe's fastest growing economic sectors, (R P G Hardy1®.)

Figure 25.5

Conserving buildings creates many useful jobs and helps promote heritage-led tourism, one of Europe's fastest growing economic sectors, (R P G Hardy1®.)

that the infrastructure of our towns continues to be used. Existing buildings tend to be located in central areas where public transport links are strong, and the network of community, health and educational facilities exist. To retain such buildings maintains the physical, social, aesthetic and energy resources of towns.

Demolition should only be a last resort. It has frequently in the past been the first decision made by the developer or the architect. Whilst many older buildings are poorly insulated and suffer from inefficient heating systems, it is generally more cost effective, and certainly more resource conscious, to recycle than demolish and bear the heavy construction and energy costs of rebuilding. The process of constructing buildings uses about 4 per cent of Britain's total energy consumption and contributes to a wide range of other adverse environmental impacts.

Where recycling is possible, adaptation and refurbishment should be undertaken with environmental considerations in mind. The high thermal mass of many existing buildings encourages the use of passive solar principles, and the shallow floor plans and relative lack cf height of older structures means that movement through the building, lighting and ventilation can all be achieved by non-mechanical means. Whilst existing buildings are often aesthetically pleasing, they also offer cheaper floor space than new buildings, thereby maintaining the social and economic mix of urban areas. They often provide exemplars of energy-efficient design since many were constructed when energy and building materials were relatively expensive. The vernacular tradition of many older buildings embodies 'green' principles of value today such as centrally placed hearths, orientation which takes advantage of solar gain by placing living or public rooms on the southern aspect, large sheltering roofs which provide living or storage accommodation within, and an even spacing of windows for well-distributed natural light.

Demolition in the UK is not controlled under planning law except in conservation areas and with listed buildings. Though planning consent is needed to undertake development, it is not required for demolition. This anomaly allows many structurally fine and socially useful buildings to be demolished every year in spite of the obvious benefits. If energy and environmental costs were considered part of town planning responsibilities then more existing buildings would be recycled.

The need to consider the recycling of buildings as a whole places new responsibility upon the shoulders of those who design them. Certain building types are more conducive to reuse than others. Those with simple forms, well constructed, and flexible in use have greater robustness in terms of the demands likely to be made by future generations. The adage 'long life, low energy, loose fit' applies equally well today as it did when it was coined over twenty years ago.

Eye Power Station in Suffolk was Britain's first electricity generating station powered by poultry litter. Built in 1993 by the Danish energy company Aalborg Ciserv International for Fibrowatt, the company established to run the plant, it has a capacity of 12.5 MW - sufficient to supply 12 500 homes. The power station burns 125 000 tonnes cf poultry litter per year which is about half of Suffolk's annual poultry litter waste.4

JArchitecture Today 3i, p 49.

The benefit of the power station is twofold. First, it saves on fossil-fuel consumption thereby reducing emissions of CO2 which add to global warming and second it reduces pollution which results from high concentrations of poultry manure. The plant utilizes the greenhouse gas methane released into the air by poultry waste and burns the nitrates normally released into local water courses. Fibrowatt claim that the plant will produce a saving of 70 per cent in greenhouse gas emissions compared to a coal-fired power station cf similar capacity.' A further benefit is the production for sale of nitrate-free fertilizer which is a by-product of the generation of electricity at the plant.

The power station was designed by architects Lifschutz Davidson with energy consultants Foster Wheeler. The design is compact yet elegant and with its high level of landscaping is intended to be an exemplar project for the 'green' community-based power station of the future. Built on a disused airfield with other business units nearby, the Eye Power Station was privately funded with grant assistance by the UK Department of Energy and the EC under the Thermie programme. As a demonstration project the design of the power station puts particular emphasis upon reducing visual impact (Figure 13.5). The bulk of the plant is broken up into separate units, each expressed in a different profile of cladding, and structural elements are exploited to break up the planes of wall and roof. To reduce the visual impact further a high grass bank surrounds the site with dense planting of deciduous trees on its outer slope. Attention to detail has helped reduce the apparent scale of the building - an important consideration if such power stations are to be built in residential areas. A single stack deals with the emission of waste air and gases.

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Responses

  • Jack Birch
    Being involved in Construction Waste Management I came across this post and was intrigued by the fact stated that Eye power station uses half the poultry litter produced in suffolk! I understand the constraints placed on any idea by cost etc but surely this initiative and clear benefits in every aspect crys out for further investment especially when one bears in mind there is sufficient fuel source for at least one more station from poultry waste in suffolk alone. Why is this not more widely publicised?
    8 years ago
  • marina
    How many building waste to energy germany?
    8 years ago

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