The project started with a systematic review of the 22 main waste fractions in the ISAG
system (see Appendix A). Hazardous waste was not divided into sub-fractions, as the
indicators proposed are not expected to provide substantial new information on the
environmental impacts of the fractions.
In the review of environmental issues for the 22 fractions, each fraction has been
labelled with one or more crosses showing where there are significant differences in
environmental impacts from typical treatment of the different fractions. Table 3.1
summarises these crosses, subsequently used in choosing parameters to be included in the
new indicators. Data accessibility is another area of significant importance for the
extent of work in the calculation of LCA-based indicators, and the result of the review is
summarised in Table 1.1 in Appendix B. Accessibility and suitability of data are
subsequently treated in more detail in Chapter 6 in connection with the assessment of the
amount of time required to prepare indicators for the entire waste management field.
It is important to realise that the crosses in Table 3.1 are relative within the
fraction, and that they express expected significant differences among the typical
treatment options. Crosses are based on a life-cycle perspective, so that for example
plastic incinerated instead of plastic recycled gives a cross for smog. Incineration leads
to a need for production of virgin plastic giving a contribution to VOC pollution. Thus,
crosses are meant to show where to find the "focal points" within the different
waste fractions.
A comparison between information in the table and waste quantities registered for each
fraction brings us closer to clarification of the waste fractions representing the largest
environmental potentials for change, and those representing insignificant areas of effort.
Table 3.1 summarises all tables of Appendix A where grounds are given for the
allocation of the crosses in the table. It gives an outline of parameters with the largest
impact in the choice of treatment option for all waste fractions.
Both energy-related resources and pollution, and resources not related to energy
consumption are important in the choice of treatment option for by far the major part of
waste fractions. In addition, landfill requirement is a possible consequence in the choice
of treatment option for most waste fractions, and it is thus an important factor for a
number of waste fractions.
Emission of toxic compounds to the environment is also a problem covering a large part
of waste treatment. For toxic impacts, heavy metals or persistent organic compounds are
found for almost all waste fractions. These substances cause problems – for some
treatment options considerably more than for others. For all waste fractions with a cross
in the energy column, the energy-related differences among the different treatment options
may be considerable. Thus, there will be differences both in relation to influence on
global warming and acidification that relate to energy issues. All energy-related
environmental impacts are not included in the allocation of crosses in the other columns.
The only essential impact on global warming that is not related to energy consumption
is the emission of methane gases from organic waste fractions, where the choice of
treatment option may be of significance.
Regional impacts from acidifying or eutrophying pollutants that are not related to
energy may be due to, for example, paper causing water contamination upon recycling.
Issues relating to working environment seem to be related to certain manpower-intensive
fractions, such as sorting paper and plastic into sub-fractions instead of incineration.
Crosses, however, have been set based on very rough estimates in the review.
The other issue examined in the review of the different waste fractions was an
assessment of data sources in addition to the basic ISAG data. This review is included in
the analysis of amount of time required to carry out a comprehensive mapping of the waste
management field (see Chapter 6).
In order to calculate an LCA indicator it is necessary to be able to break down the
mixed fractions into materials and analyse these between relevant treatment options. Only
in this way will it be possible to link relevant LCA data to disposal of materials.
Problems of data especially concern the mixed fractions for incineration and
landfilling, as these fractions stand for considerable quantities, and as no continuous
studies of waste composition are made. This applies particularly to "mixed
burnable", "non-burnable waste" and "construction and demolition
waste", but also to "metals" that cannot be specified in more detail. For
all mixed fractions extensive studies will be required to update the break-down into
materials regularly.
Thus, ISAG statistics as they are today are not particularly suitable for stating
anything on the fate of the different materials. This would require a more specific
analysis of where the different materials end up upon disposal. This is done for a number
of materials in the so-called material-flow statistics that have been prepared especially
for a number of packaging materials, and a number of mass-flow analyses that have been
prepared particularly for heavy metals. ISAG statistics may be used in particular for
stating environmental impacts from management of waste fractions currently separated for
reprocessing. If more detailed material flow/mass-flow analyses are available, it will
also be possible to assess the environmental and resource-related potential from a change
in waste management. Chapter 6 and Appendix B estimate the amount of time required to
collect data for the individual waste fractions.
Table 3.1
Differences in environmental impacts in typical treatment of different waste
fractions
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3.3 Conclusions on choice of
indicators
Investigations indicate that as a minimum LCA-based indicators should and can include
energy and resource consumption and landfill requirement. Toxicological issues are also
important, but here, it may very demanding to provide LCA data for use as a waste
indicator. For issues relating to working environment it is not yet possible to find
sufficient data for analysing in the same way as for other parameters (see Chapter 2.3).
For the mixed group for incineration, several investigations have been carried out
focusing on an analysis of contents. Here it will probably be possible to find data for
preparation of a status of environmental impacts and resource consumption. In this way it
will also partly be possible to divide the mixed fractions into materials and treatment
options, which is necessary to calculate the three LCA-based indicators. For more detail,
see Chapter 4.
Furthermore, the screening indicates that there may be great difficulties in finding
data for all fractions. In Chapter 6, the extent of calculating LCA indicators for the
total Danish waste management system is analysed.
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