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Waste Indicators

2 From waste quantities to environmental impacts

In this chapter, the general idea of developing indicators in the field of waste management is described. Furthermore, the difference between indicators for environmental impacts and existing quantitative waste statistics is discussed.

2.1 Present indicators for waste management

Indicators applied today to follow developments in waste and recycling in Denmark are merely quantitative statements of total waste quantities broken down on treatment and disposal options.

It should be noted that whereas disposal patterns depend on political measures within the waste management field, waste prevention rather depends on measures in relation to manufacture and consumption of products. However, consumption is beyond the scope of this project, which focuses on disposal by incineration or landfilling or on reuse/recycling of waste.

2.1.1 Existing statistics on waste

Figure 2.1 is reproduced from Waste Statistics 1998. It compares total waste quantities and treatment with objectives for year 2004 in the Danish Government’s Waste Management Plan.

Figure 2.1
From "Waste Statistics 1998" /40/

Target 2004: Target for year 2004 in the Danish Government’s Waste Management Plan /37/.

General waste indicators are determined today by aggregating all waste categories on the basis of quantities. In aggregated indicators (as in Figure 2.1) garden waste quantities, for example, have the same weight as scrap aluminium quantities, even if environmental impacts are very different.

It is important to realise that new LCA-based indicators for waste are expected to serve as a tool in particular for public authorities responsible for waste management. Present statistics serve the same purpose, since planning of new initiatives for waste and recycling is based on, for example, existing knowledge of the extent of waste problems and present management. Planning of treatment capacity and financial optimisation of, for example, incineration, landfilling or reprocessing plants for recycling often requires detailed knowledge of waste streams. Also national initiatives to regulate waste quantities and treatment options require a statistical basis for mapping and analysing development needs.

The Danish Information System for Waste and Recycling – the ISAG – is based on a statement of collected waste quantities in a number of categories in harmony with EU legislation and the so-called EWC codes for hazardous waste. Waste treatment plants are responsible for registration and reporting to the authorities. As ISAG registrations are well-established and the use of EWC codes is relatively new in Denmark, ISAG statistics are in many ways more accurate, even if – in principle – EWC codes give a more detailed picture for hazardous waste.

It is estimated in the project whether ISAG statistics can be used as the basis for an indicator calculation. Once the use of EWC codes has gained more ground it may be relevant to include this registration in a future indicator calculation to the extent that hazardous waste is to be included.

The ISAG system contains data for fractions subjected to separate waste treatment, such as paper for recycling or domestic waste for incineration. For a number of fractions, waste statistics may be related to and supplemented with other statistics. For example, production and supply statistics may be related to waste statistics, thus giving a picture of the destiny of goods manufactured in the fractions of waste statistics. So far this has been done for a number of materials in the so-called material flow statistics. In this way it is possible to calculate for a number of material fractions the proportion of materials consumed that is disposed of by recycling, incineration or landfill.

There are two central ways of presentation and use of waste statistics:

1. Developments in total waste quantities broken down on sources and sectors such as households, industry and commerce, bulky waste etc. Such statements make it possible to target efforts in the waste management field towards the most relevant sectors.
       
2. Treatment options broken down on a number of waste types. Treatment options cover recycling, incineration, landfilling and special treatment. For waste led to recycling, statistics are broken down on a number of specific material fractions. The statement makes it possible to calculate the rate of recycling, expressing to some degree compliance with political objectives for increased recycling.

Present statistics form the basis for planning of waste management, for example in relation to extension of treatment capacity. When, in fact, it is problematic to only look at quantities and rates of recycling for the different sources of waste, it is because environment and resource problems relating to the different waste fractions are not stated and assessed. Neither is it possible to assess environment and resource issues relating to different treatment options for waste fractions, and the advantages of one treatment option over another do not appear.

In addition, a number of environmental issues exist beyond waste management as such, but for which waste treatment has decisive influence on environmental impacts. New indicators therefore must be based on a life-cycle perspective, incorporating in principle all environment and resource related changes caused by the different waste treatment options.

2.1.2 Purpose of new indicators

Below, the possibilities of developing indicators to reflect also more directly the resource and environmental impacts caused by waste management are discussed. Indicators will be developed from a life-cycle perspective. In the considerations it is essential to have two levels of indicator use in mind:

Total waste quantities. In a comparison and aggregation of indicators for the different waste fractions, new indicators may to a higher extent reflect real energy, resource and environment-related consequences of developments in the field of waste management. This type of statement may be used to prioritise efforts based on waste fractions constituting the largest impact or the largest loss of resources. However, to do this it must be possible to develop indicators that can be applied to most waste fractions.

Individual waste fractions. New indicators on individual waste fractions may take into consideration that the waste hierarchy for different treatment and disposal options in some cases does not reflect real differences from an environmental perspective. Such use of indicators does not require that indicators are applicable for several waste fractions, but rather that they contain data allowing for comparison of different treatment options for the same waste fraction. What is important here is to show resource and environment-related differences among treatment options.

Finally, it is important to bear in mind that ambitions for use of indicators may differ. If the purpose is to follow closely developments over a number of years, and indicators should be used to adjust waste policies continuously, it is important that indicators can be updated regularly – for example annually, and that analyses are available within a reasonable time frame.

However, if it is the ambition to draw up a status at, for example, five-year intervals, and it is acceptable that completion of the analysis is relatively time-consuming, requirements for data sources are different. In this case it will be possible to a higher extent to draw on statuses, specific studies of individual fractions etc.

The purpose of establishing indicators is to supplement quantitative statements with environment-related indicator values liable to be incorporated in the basis for prioritisation in the revision of waste planning. It is expected that this will be done continuously, but with an overall revision every three to five years.

The aim of the present project is to establish indicators that may be updated annually for all waste fractions so that environment and resource indicators are available that may supplement existing waste statistics. Due to insufficient data, however, it may be necessary to change the objective for completion of indicator calculations. For some waste fractions it is expected that calculations will be completed only with some years’ interval. Chapter 6 discusses which fractions are relevant for continuous update and which are relevant for periodic updates.

2.2 Indicators developed for LCA

In the development of new indicators for waste management based on life-cycle considerations, it will be expedient first to relate to indicators used within LCA, and in particular the Danish EDIP method /11/(Environmental Design of Industrial Products) (see Glossary).

2.2.1 Environment and resource indicators in EDIP

The EDIP method only aggregates data in the grouping of the different impact categories as mentioned above (see Glossary). But to bring the size of impact categories to the same scale, for each impact category, furthermore, a normalisation is carried out in relation to global or regional emissions or consumption per person (see Glossary). This means that all emissions or consumption are expressed as person-equivalents (PE) in relation to present consumption and emission per person. Person-equivalents express how large a proportion of present consumption or emission may be attributed to the product or area under review.

The EDIP method, in addition to normalisation, suggests how to weigh some impact categories so as to make them more comparable – however without making a direct aggregation of the individual factors (see Glossary). However, in principle it will be possible to do so for environmental impacts and resource consumption respectively, which has also been done in several other contexts.

Environment and health parameters: If a weighting is made of the many types of environmental impacts, it is advantageous to distinguish between human and ecotoxicological parameters and other parameters, the former being in general very uncertain and often lacking good data for statements.

Resource consumption in the EDIP method is handled by relating consumption of each resource to total global reserves of the resource in question. A distinction is made between renewable and non-renewable resources. Renewable resources are weighted with 0, unless they are extracted to an extent that the accessible quantity is presently being reduced- - for example, the resource "groundwater" in Denmark the extraction of which in certain parts of the country is larger than its regeneration. Weighted resource consumption thus achieved may be aggregated to a collective indicator for resource consumption.

Waste disposal by landfilling in the EDIP method is handled with the above four different waste categories led to landfill, as so far no statements have been made of release to the surroundings of pollution and resources for the entire period of landfilling. Waste to landfill is derived from all life-cycle phases; for example, mining waste is also included in the four waste categories. However, accessible databases are often insufficient in this respect. Waste landfilling may be aggregated according to the same principle as other environmental EDIP parameters, i.e. it can be normalised and weighted with the political reduction objectives.

Working environment, from experience, is difficult to handle, if the assessment comprises many different processes. In the ongoing project on further development of the EDIP, a preliminary report has been published, quantifying working environment impacts in a number of sectors, based on existing statistics.

However, waste treatment and recycling industries have not been stated separately, partly because the sector is relatively new and small and therefore not treated separately in overall statistics, and partly because systematically collected experience with working environment in the recycling industries is very limited /19/. However, a number of studies of working environment conditions in waste management have been launched, and thus it will probably be possible to acquire relevant data at a later stage.

2.3 New indicators in the field of waste management

In Chapter 4 methods for calculation of new waste indicators are reviewed on the basis of resource and environment issues associated with disposal of the different waste fractions. Results will be presented in two basically different ways, based on the same calculation principles.

2.3.1 Basic principle for indicator calculation

The calculation of life-cycle-based indicators for waste management is based on the principle that society’s material consumption is constant or increasing in the period of time for which the calculation should be used. This means that if any material is removed from circulation, either through landfilling or incineration, virgin raw materials must enter the system to replace what was lost. However, it is possible that in a mapping of the entire field of waste management, materials will appear for which this assumption does not hold true. This may be the case, for example, for use of materials that are undesirable from an environmental viewpoint, and a decision has been taken to phase them out completely. In such a situation the consequence may be that recycling of the material is of no value.

Another necessary assumption is to calculate parts of the life-cycle for products: parts concerning raw material and material production and waste treatment. To the extent that materials are recovered or replace other materials before they are lost through incineration or landfilling, they will also be incorporated in the calculation as a reduction of material consumption.

By contrast, product manufacture and use of products are not included in the calculation. This assumption was necessary, as it is not possible to get data on manufacture of products that ended up in a given waste fraction.

Figure 2.2
Illustrates the system boundaries in the calculation. Please note that product manufacture and use are not included

Of course, this model may be discussed, and it does influence the use of indicators. If the purpose is to assess which "value" waste represents, the model should be extended to cover also some more detailed considerations on discarded products’ utility value and durability. Which utility features are we discarding and what was the cost of producing these products? Such questions easily trigger extensive and difficult considerations on how to distribute responsibility for a product’s material and utility features among designers and users of the product and those who are responsible for the product’s management as waste.

The calculation is based on the manufacture of materials lost in waste management in different ways. This result gives a calculated value for lost resources that may easily be confounded with an "absolute value" for waste. For example, one tonne of aluminium led to landfill will have a higher value – be more expensive to dispose of – than one tonne of aluminium led to recycling.

As mentioned above, many factors of a material’s life-cycle are not included in the calculation, so in principle it would be more correct to use only calculations for looking at differences among different options for waste management. In this way some of the unknown factors are eliminated, and the result can still be used for expressing the efficiency of waste management. However, this does not exclude comparison of different materials. It only means that it is more correct to compare environment and resource savings from management of materials in different treatment systems.

2.3.2 Accessible data

One of the important features of the ISAG today is that the grouping of waste in sources or fractions is the result of a number of practical and historic issues. This division is not necessarily the most expedient for making, for example, an LCA assessment of waste management, and neither is it always the most expedient basis for giving an outline of the fate of different material fractions upon waste treatment. In general, emphasis has been put on statements of material flows treated separately, for example materials for recycling.

The purpose of continuous statistics as a supplement to the ISAG (see Chapter 3) is often to map waste streams for specific materials or products. Such statements are necessary for conducting an LCA assessment of waste streams. At the same time these statements form the basis for presenting LCA calculations at the material and product levels, which is also useful in connection with, for example, implementation of a product-oriented environmental policy.

In the longer-term perspective it may be relevant to try to adapt waste statistics, which is being done today on an ad hoc basis. The need for any new categories that may ease calculations of LCA-based indicators, will be treated in connection with the trial run under the present project on indicators for selected waste streams.

2.3.3 Presentation of results

Chapter 5 proposes two ways of presenting data, each focusing rather differently on the waste question. The two proposals are based on considerations of calculation principles and accessible data.

Whereas one of the proposals seeks to provide a total picture of environmental and resource impacts from waste using present management techniques, the other proposal puts focus on showing results achieved and, to some extent, which potentials may be gained from changing waste management. The two ways of presenting results of indicator calculations have slightly different assumptions for data, and they may supplement each other if data is available to conduct all calculations.

It should be noted that new indicators are to be seen as a supplement to indicators already in use in the waste sector. Waste quantities are still to be seen as an important indicator for the area and will still be used as the basis for design of, for example, landfills, incineration plants and other treatment plants. Furthermore, waste quantities within the different fractions still constitute an essential part of the basis for calculation of new indicator values. The new LCA-based values, by contrast, are expected to give a considerable contribution to the prioritisation of different waste fractions or treatment options.

2.3.4 Which indicators are relevant?

The analysis presented in Chapter 3 indicates that in addition to resource consumption and landfill requirement there are a number of different environmental impacts, for example eco and human toxicity, that are important in relation to differences among different treatment options for the different waste fractions.

On the basis of an analysis of accessible data for waste treatment presented in Chapter 3 and accessible data from the EDIP project, it is realistic to carry out calculations for resource consumption, energy consumption and landfill requirement.

Energy consumption is not used as a category in the EDIP, since energy consumption is included in resource consumption and derived environmental impacts. However, on the basis of EDIP data for energy resources it is relatively simple to calculate a primary energy consumption (see Glossary). Consequently, in the trial run, a parameter for primary energy will be calculated that may be normalised in relation to total Danish primary energy consumption. In this context, energy consumption should be seen as a measurement for a number of energy-related environmental impacts of which global warming is most directly linked to energy consumption. Resource consumption for energy is also included in the statement of resources, but here consumption is included as the weighted resources – and not due to their environmental impacts. In the resource statement it should also be possible to distinguish between energy and other resources, and it should be possible to distinguish between renewable and non-renewable resources.

For the human and eco-toxicological parameters used in the EDIP project, data is often insufficient. At the same time, the basis for calculations is insufficient for waste quantities, since waste statistics do not have the direct, detailed statements for different materials that are necessary for LCA calculations. This gives reason to re-evaluate the relevance of calculating ecotoxicological parameters as indicators in the field of waste management.

Previously, experience has been gained from including environmental impacts in large prioritisation projects. In connection with the project "Environmental prioritisation of industrial products" /15/ originally only resource and energy consumption was included. A subsequent pilot project /10/ investigated whether it was possible to qualify prioritisation by including environmental impacts in the calculations. Experience showed that resources needed to collect data, particularly for toxicity parameters, were excessive compared to the outcome that was anyhow very uncertain. Similar experience has been gained in the project "Environmental impacts in the family" /14/, in which inclusion of the environmental impacts of ecotoxicity and human toxicity was considered, but rejected.

Therefore it is suggested that these parameters are not included directly in the indicators to be tested. The omission of ecotoxicological parameters means, however, that indicators are not adequate for the assessment, for example, of hazardous waste, which as a consequence should be excluded from indicator calculations or supplemented with other assessments.

The analysis in Chapter 3 also indicates that for some waste fractions there may be significant differences in working environment impacts from different treatment options. However, it is extremely difficult to quantify working environment conditions in recycling industries. But principles for this may be set up, cf. sub-project on working environment in the ongoing development project on the EDIP method and data for LCA assessments. However, it is assessed that work required is excessive compared to the expected result, due to lack of data in this field.

Against this background it has been decided to use the parameters below. Determination of units is discussed in Chapter 4.2, and units used are explained in the Glossary.

Resource consumption (in PR – person reserves)

Resource consumption is stated by converting the weight of each individual material to a proportion of the existing resource basis. In other words: what is the proportion of a unit of weight of the material in relation to existing material quantities per person. For non-renewable resources, the existing quantity is calculated per person in the world, and for renewable resources in relation to accessible quantities per person in the region. If a renewable resource is regenerated at least as fast as present consumption, supply is infinite, and consumption is weighted at 0. For example, this applies to the use of surface water. Principles follow the statement methods of the EDIP project /11/.

Energy consumption (in PE – person equivalents)

The unit for energy consumption is annual primary energy consumption per person in Denmark, which is set equal to one person equivalent. This is not included in the EDIP project, but is used here as a total measurement for environmental impact from energy conversion.

Landfill requirement (in PE - person equivalents)

The unit for landfill requirement is the present landfill requirement for waste in Denmark per person. This parameter is used due to lack of more specific parameters for landfilling, which are being developed in connection with the LCA method. The indicator is different from the four waste categories for landfilling under the EDIP project, as all waste for landfilling is collected in one category.