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Waste Indicators 1 Waste indicators - trial run
Part of the project involved a trial run of the indicators, which were calculated for three selected material fractions, namely paper and cardboard, glass packaging and aluminium. The purpose of this trial run was not to present a final, complete result of the indicators. The calculations should therefore be considered as examples that illustrate how the indicators can be used and presented. The indicators calculated for the three fractions will inevitably have to be updated, in the event that indicators are calculated for the entire field of waste management. In this chapter results of calculations are summarised. In Chapter 5 and Appendix D all results as well as the calculation basis are presented. Appendix D has not been translated. The indicators are based on life-cycle considerations, which implies that resource consumption and environmental effects are included from the extraction of raw materials to waste disposal. As principle all input and output flows are included in the calculation. But when practising the impact assessment it will be necessary to leave out some input and output due to lack of data. It will therefore be urgent to mention this by presentation of the results. In the calculations, it is assumed that new materials are to be produced to substitute all waste materials that are discarded. If material is disposed of by landfilling, resources and energy will be required for the production of new material. Waste will also be generated during the extraction and processing of new material. If material is recycled instead of being landfilled, less new material will have to be produced. Similarly, some energy can be recovered from waste material with a calorific value. The calculation of indicators is based on a series of assumptions and are also subject to a certain degree of uncertainty. The results are therefore not suited for presentation to a wide audience, but can form part of the basis for making decisions, with the aim of prioritising efforts to optimise waste management. This includes both an assessment of which waste fractions have the greatest resource consumption and environmental impacts and which treatment options are the most appropriate for each waste fraction. Indicators can thus supplement the existing information on individual waste quantities for waste fractions, sources and treatment options, thereby making it possible to prioritise efforts to minimise the resources consumed and environmental impacts of waste management, as well as efforts to avoid treatment options that increase the total landfill requirements throughout the life-cycle of a given material. 1.1 Preliminary calculations of waste indicatorsThe aim of testing the indicators for a few selected material fractions was to investigate how easy it is to obtain the necessary data and assess the time required to complete the calculations. It has also been possible to try out different ways of presenting the results, and two different presentation methods are suggested. Both presentation methods (referred to as Models A and B) are based on similar calculation parameters describing the life-cycles of the materials, but differ in terms of the need for precise quantitative data for individual material fractions. Data requirements are crucial for assessing the scope of work involved in calculating indicators for entire waste management systems. LCA-based parameters for resource consumption, energy consumption and landfill requirement must be determined for each treatment option for the individual waste fractions. The methods and principles are described in the project. Figure 1.1 is an example of the parameters calculated for glass packaging showing resource consumption for the relevant waste treatment options. Similar profiles for resource consumption, energy consumption and landfill requirements are presented in the project for paper, glass and aluminium.
Figure 1.1 The units are milli person-reserves mPR. PRWDK1990 is the unit for resource consumption, expressed by weighting relative to the person-reserves estimated for World/Denmark (WDK) in 1990. (See Glossary) In the first presentation model (A), the parameters mentioned above for each waste fraction and treatment option are multiplied by the total quantity of each waste fraction treated by each treatment option. For example, the quantity of glass packaging, in tonnes, that is incinerated at a waste-to-energy plant is multiplied by 9.7 mPR per tonne (see Figure 1.1). The results for each of the four treatment options are summed up and represent the indicator value for resource loss for managing waste glass. The results for the three indicators and materials are shown in Figure 1.2. Model A represents the amount of virgin resources that are required for a given material to regain its original value after the material has been used and managed as waste. In Model A, all losses of utility value that occur during the life-cycle of a product are attributed to waste management, i.e. allocation of resources and environmental impacts to the different phases in a product’s life-cycle does not occur (see Glossary). This is acceptable since the aim is to compare different waste treatment options and not to give an absolute representation of the environmental impacts of waste management. Model B calculates the resource and environmental advantages that are associated with recycling waste and recovering materials or energy as opposed to simple landfilling of the waste. The basis for the calculation is the same as in Model A, where the indicator value for a given treatment option is multiplied by the waste quantity treated. In Model B the calculations are based on the differences in indicator values and waste volumes for the different waste treatment scenarios. Thus, Model B compares the different treatment options and does not present an absolute value for the resource consumption and environmental impact of different waste fractions. Model B illustrates the resource and environmental savings realised by the present management of the waste fractions compared to landfilling all the waste generated. If desired, Model B can be developed to include a partly estimated calculation of the potential savings that could be achieved by managing waste in an optimal way, which is also attempted in the project. Figure 1.3 is an example of these savings potentials.
Figure 1.2 The following units have been used: Resource consumption: PRWDK1990; Energy consumption: PEEnergy DK98; Landfill requirement: PEWaste DK98. For more
detail, see Glossary. The values for landfill requirement should be multiplied by 10. It
should be noted that the three indicators have only been shown in the same figure for
practical reasons. Each indicator should be studied separately.
Figure 1.3 The units are person-reserves mPR (see Glossary). The significance of the potential savings can be questioned, as well as the choice of treatment options that are used to calculate the savings. In the example, the potential savings for glass packaging are calculated assuming that all glass packaging is recycled or reused. It appears that in relation to resource consumption, it is much more important to recycle aluminium and paper and cardboard, than to recycle glass. It is also seen that significant additional resources could be saved for the waste fractions paper and cardboard and aluminium. However, it is important to compare the resource indicator with the two other indicators for energy consumption and landfill requirement (see Chapter 5), and possibly include other assessments, such as potential release of toxic substances to the surroundings, before any final conclusions are drawn. 1.2 Calculating indicators for the entire waste management systemIf the aim is to obtain an overview of the relative contribution of different waste fractions to resource consumption and environmental impacts on the surroundings, Model A is the most appropriate. In this way, it is possible to identify the areas where the environmental impacts of waste management could be reduced by reducing waste generation or by encouraging the use of alternative materials during manufacturing. The approach is interesting but mainly suggests that changes should be made in the manufacturing process and in consumer behaviour, which is beyond the scope of this project. If, on the other hand, the aim is to focus on the resource and environmental savings resulting from optimising waste management, Model B is sufficient. Calculating Model B for all waste fractions would allow the most significant potential resource and environmental savings during waste management to be identified. It would also be possible to supplement with calculations that focus on identifying the fractions with the greatest savings potentials. Finally, it would be possible to limit the assessment to certain specific fractions in order to determine the resource and environmental savings associated with the different waste treatment options. Both presentation methods are based on similar calculation parameters describing the life-cycles of the materials, but differ in their need for precise quantitative data for individual material fractions. Model B is the least demanding, since it primarily uses data that can be obtained from waste management statistics describing the waste quantities and treatment options for individual waste fractions. Although it is not necessary to accurately determine the total flow of material in society in order to calculate the indicator values, as it is for Model A, additional data must be obtained in order to calculate the potential for optimising waste management. However, this data collection exercise can to a certain extent be replaced by qualified estimates, without adversely affecting the overall calculation results. No matter which model is selected – A or B – life-cycle-based factors must be calculated for around 50 material fractions disposed of in two to four different ways. Such data is widely available in the EDIP PC tool database or other LCA databases, but must be supplemented or updated in a number of fields. It is estimated that around two man-months will be needed for initial calculation of the life-cycle-based factors, and around ½ man-month for an annual updating. For quantitative data, the extent depends on the model selected. It is assessed that for a calculation of the entire waste management field for Model A 10 – 20 man-months are required to provide quantitative data for all material fractions, possibly 10 man-months more if suitable mass-flow analyses or material flow statistics for a number of relevant materials cannot be found. If Model B is selected with a calculation of realised savings and selected savings potentials from optimisation of waste management, the amount of time required to provide quantitative data will be around three to five man-months. Model B can be updated annually with an input of around one to 1½ man-months.
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