Total UK waste arisings amount to just over 400 million tonnes y~1. The Department of the Environment’s Digest of Environmental Protection and Water Statistics8 gives estimates for the annual waste arisings for the UK by sector. A summary is given in Table 1. This figure of 400 million tonnes y~1 should only be taken as an indication of the approximate order of magnitude of UK waste arisings because estimates in certain sectors are only quoted to the nearest 5 or 10 million tonnes. Research work continues with the aim of improving the reliability of these waste statistics.
In some sectors, good waste management practices exist. The level of recycling of wastes occurring is relatively high. For example, the amounts of demolition and construction wastes recycled have been estimated at 45%,9 of which some 80% of asphalt road plannings are recycled. On the other hand, only some 5% of household waste is recycled currently. Generally, for techno-economic reasons,
Industry on Recycling’, 27 July, 1993.
7 Producer Responsibility Industry Group (PRG), ‘Real Value from Packaging Waste’, February, 1994.
8 Digest of Environmental Protection and Waste Statistics, Department of the Environment, HMSO, London, No. 15, 1992.
9 Arup Economics and Planning, ‘Occurrence and Utilization of Mineral and Construction Wastes’, Department of the Environment, August, 1991.
Table 1 Estimated total annual UK waste arisings
Annual
arisings Date of
Sector Mtonnes estimate Status#
Agriculture 80 1991 NC
Mining and quarrying
colliery and slate 51 1990 NC
china clay 27 1990 NC
quarrying 30 1989/90 NC
Sewage sludge 36 1991 PC
Dredged spoils 43 1991 PC
Household 20 — C
Commercial 15 — C
Demolition and construction 32 1990 C
Industrial
blast furnace and steel slag 6 1990 C
power station ash 13 1990 C
other 50 — C
Total 402 — —
#NC \ not classed as a controlled waste under the terms of the Environmental Protection Act (Controlled Waste Regulations) 1992; PC\ sewage sludge is classed as a controlled waste as defined in the EPA (CWR) 1992 except when disposed of on agricultural land or within the curtilage of the sewage works at which it arises; dredged spoils are classed as a controlled waste when licensed for disposal under the Food and Environmental Protection Act. See Schedule 6 of the Collection and Disposal of Waste Regulations, 1988;
C\ controlled wastes under the terms of EPA (CWR) 1992.
recycling rates tend to be higher for the more homogeneous wastes: heterogeneous wastes are technically more difficult to deal with.
At Warren Spring Laboratory (now merged with AEA Technology to form the National Environmental Technology Centre), the Waste Research Unit has concentrated its monitoring and analysis expertise towards relatively heterogeneous wastes such as household wastes and commercial wastes. For example, the National Household Waste Analysis Project funded by the Department of the Environment continues presently. Its aims are:
f to provide data on the composition and weight of household waste which is representative of the UK as a whole;
f to have the potential to predict the composition and weight of waste arisings at a local (e.g. local government authority) level; and
f to provide information which will underpin work to identify more efficient resource and waste management practices in the UK, including waste minimization, design for recycling and disposal, waste collection practices, and treatment and residue disposal.
Resulting from this project, the typical composition of UK household (dustbin/garbage can) waste has been determined and is given in Figure 1.
The recyclable components of household waste are shown in Figure 2. The
Figure 1 Typical composition of UK household (dustbin) waste
Table 2 Recyclable components of household waste
Potential available
Weight/ amounts*
Component % /Ktonnes year~1
Newspapers and magazines 16.1 2335
Plastic bottles 1.9 276
Glass bottles and jars 9.1 1320
Putrescibles 20.2 2929
Food and beverage cans 4.3 624
Aluminium beverage cans 0.4 58
Totals 52.0 7542
*Calculated using a basis of 14.5 million tonnes year~1 household waste arising Figure 2 Recyclable
components of household (dustbin) waste
potential recovery of substantial amounts of usable materials is also clearly shown in Table 2.
When deciding and selecting measures within the broad framework of current policy and strategy, it is important to keep the following statements in mind.10 (i) Waste is material in the wrong form or place—it takes energy to put it back
into productive use—i.e. energy is the ultimate resource.
(ii) Waste is a consequence of resource use. Of itself, it is not evidence of failure.
Inefficient use of resources and poor waste management is.
Resource conservation is the key to reduction of wastes. This can be achieved
10 J. R. Barton, ‘Priorities for the Future’, Paper W93014, Warren Spring Laboratory, to NSCA 1993 Workshop ‘Waste Management, New Approaches, New Priorities’, 23/24 March, 1993, Lincoln College, Oxford.
by a number of methods:
f by reducing consumption;
f by improving primary extraction processes;
f by fabrication/manufacturing design;
f by improving product life;
f by lightweighting;
f by re-use/refilling/recharging;
f by recycling; and f by energy recovery.
Recycling is just one option for achieving resource conservation.
3 Recycling
In a free market situation, there are four basic, linked requirements which need to be in place before materials recycling can occur successfully. These are:
(i) there must be a reliable supply of suitable waste materials;
(ii) there must be the means to collect these materials and to transport them to a place where they can be re-processed;
(iii) there must be the means to re-process these materials into suitable raw materials and products; and
(iv) there must be available markets for the raw materials and products produced by the recycling process.
Economic considerations have a major influence on whether these four basic requirements can be achieved all at the same time. Failure to achieve one of the requirements will result in failure for materials recycling.
Additional factors influencing the uptake of recycling include efficiency of the recycling process, quality of the input material, quality of the recycled output materials, profit margin potential (to ensure a reasonable pay back period on investment in recycling equipment and technology), economic and environmentally appropriate outlet for wastes generated during the recycling process and location of recycling (e.g. close to major sources of waste arisings or close to customers for the recycled materials, etc.). The net effect of all these factors is that an optimum level of recycling will exist for a particular material which is dependent on a balance of these interacting factors. In the real world, a 100% recycling level is unlikely to be an optimal solution in waste management.