Strategic environmental assessment as an approach to assess waste management systems. Experiences from an Austrian case study

Environmental Modelling & Software 22 (2007) 610e618 www.elsevier.com/locate/envsoft

Strategic environmental assessment as an approach to assess waste management systems. Experiences from an Austrian case study Stefan Salhofer*, Gudrun Wassermann, Erwin Binner Institute of Waste Management, BOKUdUniversity of Natural Resources and Applied Life Sciences, Vienna, Austria Received 25 October 2005; received in revised form 6 November 2005; accepted 15 December 2005 Available online 31 March 2006

Abstract Waste management has evolved from the simple transportation of waste to landfills to complex systems, including waste prevention and waste recycling as well as several waste treatment and landfill technologies. To assess the environmental, economical and social effects of waste management systems, several tools have been developed. Strategic Environmental Assessment (SEA) is an approach for integrated assessment enhancing involvement in the planning of a decision supporting process. The aim of this paper is to show how SEA can be applied in a waste management context. For this purpose a case study is described where a SEA process was undertaken to develop a regional waste management plan. The approach from this case study is compared to other methods. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Waste management; Strategic environmental assessment; Life cycle assessment; Participation

1. Complexity in waste management 1.1. Development of waste management systems Waste management has evolved from the simple transportation of waste out of settlement areas to more complex systems including recycling and prevention of waste. Until the 1960s municipal waste management was concentrated on the collection and transportation of waste without any separation from households to the disposal facilities, which in the majority of cases were local dumps or landfills. Processes were planned or optimised merely on the basis of efficiency in terms of costs. Environmental effects were only marginally taken into account. In a second phase, waste treatment and landfilling technologies were improved. This was triggered by the considerable environmental damage caused by dumps and landfills, by increasing quantities of household waste and changes in composition. Typical improvements were represented by the

* Corresponding author. E-mail address: [email protected] (S. Salhofer). 1364-8152/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.envsoft.2005.12.031

development of flue gas scrubbing technology for MSWI (municipal solid waste incinerators), the installation of base liner systems in landfills to collect sewage, etc. Additionally, research on waste recovery and recycling was stimulated by the energy crisis. For the first time therefore the aspect of waste as a resource was taken into consideration. Complex waste management systems in industrialised countries were first introduced and further developed from the 1980s onward. These include source separation of recyclables and hazardous waste as well as facilities for recycling and composting. Specific treatment technologies for several types of waste were introduced, together with advanced landfill technology whereby barrier systems were applied in order to reduce sewage and landfill gas. Over recent years, waste strategies have been supplemented by product related regulation, e.g. the EU has passed regulations on packaging, end-of-life vehicles and electrical and electronic equipment, rendering the producer responsible for the entire life cycle of products. Currently applied waste management systems are somewhat complex, for example in some Austrian regions up to 15 different types of waste are collected separately and transferred to different recycling and treatment facilities. From

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a citizen’s point of view waste disposal has become expensive, requires additional space in the household and is time consuming. It is not really surprising that some authors, e.g. Kaimer and Schade (2002), argue in favour of a regression, once again making waste collection systems simpler and more convenient for the citizen. Overall it has become a rather sophisticated task to forecast the consequences of waste management strategies in their environmental, economic and social aspects. 1.2. Assessment of waste management systems As a result of the increasing complexity of waste management, adequate computerised assessment tools have been developed. A first generation of models was developed in the 1970s, analysing practical aspects such as the routing of collection vehicles or location of disposal facilities. The cost issue for these models was the main decision variable. In a second generation of models developed in the 1980s, environmental aspects were included. Bjo¨rklund (2000) describes three types of model. One type of models analyses different recycling schemes, e.g. Barlishen and Baetz (1996) in terms of cost minimisation, while environmental benefits or drawbacks of recycling are not considered. A second type of model analyses the costs of technical solutions that meet the environmental constraints, e.g. Chang et al. (1996). A third type explicitly calculates environmental parameters, aiming at optimisation, scenario analysis or multi-criteria analysis. In the 1990s, a third generation of life cycle assessment (LCA)-based models were developed and applied. The more widely acknowledged models are WISARD (Waste Integrated Systems Assessment for Recovery and Disposal), cf. Aumonier and Coleman (1997), IWM (Integrated Waste Management), cf. White et al. (1999) or the Swedish ORWARE model, e.g. Bjo¨rklund et al. (1999). Typical results from these models pertain to environmental effects in 5 to 10 impact categories. In some cases, the single indicators are weighted, whilst in others this does not occur. The increasing demand for types of models which combine environmental, economic and further aspects (like social, technological aspects) has led to the development of a latest generation of computerised models, which are similar to the LCA-based models, but include additional cost effects and/ or social effects. In this case, cost effects can be regarded as an additional impact category. Examples of this type of models are GABI and Umberto, well known computerised tools especially in the German speaking community. The IWM-2 model, cf. McDougall et al. (2001) is an expansion of the IWM model. Both concentrate on Waste Management, whereas GABI and Umberto can also be applied to other LCA issues beyond that of Waste Management. A comparison of these models has been reported by Unger and Wassermann (2003). From both a methodological and a practical point of view it is a complex task to compare alternatives with respect to environmental effects, costs and social aspects. In most cases, the antagonistic targets of cost minimisation, reduction of environmental effects and high convenience for the user (mainly of the waste collection scheme) cannot be met by one single

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scenario. It is increasingly likely that a scenario in which high costs are linked with high environmental standards and high convenience will be involved, whereas low-cost scenarios prove to be less environmentally friendly or less convenient. 1.3. SEA in waste management With regard to waste management, the opposite interest groups are often rather relentless. Representatives from municipalities, who prefer technical solutions, are in conflict with representatives from citizen’s groups or ecologically oriented NGOs who prefer waste prevention and recycling as solution strategies. Furthermore, as a general rule residents tend to object to the planning and construction of waste management facilities. A participatory process may be of help in reducing these problems in a planning process from the very beginning and contribute towards defining acceptable solutions for all parties involved. A Strategic Environmental Assessment (SEA) is a general approach to incorporating environmental considerations in the development of plans and programs. A commonly used definition of SEA is: ‘‘a systematic process for evaluating the environmental consequences of a proposed policy, plan or program initiative in order to ensure they are fully included and appropriately addressed at the earliest appropriate stage of decision-making on par with economic and social considerations’’ (Sadler and Verheem, 1996, cited in Nilson et al., 2005). SEA can also be regarded as a decision support process, especially when applied to the development of a plan. This is the major difference to Environmental Impact Assessment, which deals with a single project and therefore is much more site specific. Details on SEA are defined under the Directive 2001/42/EC, which must be implemented by the Member States by July 2004. As a consequence, a SEA process will be mandatory for waste management plans in the future. Compared to other methods of decision support like traditional life cycle assessment, SEA represents an approach for integrated assessment at a strategic level. For details on aspects of integration see Bond et al. (2001). Participation is an essential element of the SEA process. Furthermore, participatory processes have been established by the directive 2003/ 35/EC, the public access information directive 2003/4/EG and by the methodology of Sustainability Impact Assessment, cf. Kirkpatrick and Lee (1999a,b). The latter was developed to make a broad assessment of the potential impacts. The assessment process contains four main stages, including a screening (to determine which measures have a significant impact and require SIA), a scoping (to establish an appropriate coverage of each SIA), a preliminary sustainability assessment (to identify significant effects) and a mitigation and enhancement analysis to suggest types of improvements (Kirkpatrick and Lee, 1999a,b). As SEA is a relatively new approach, the process design is not homogeneous. Finnveden et al. (2003) identified the following steps in the process:  definition of objectives,  formulation of alternatives,

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 scenario analysis,  environmental analysis (based on natural sciences),  valuation (including aggregation methods and political and ethical values) and  conclusions, review of quality, follow up measures. To date, SEA as participatory process for waste management has only been conducted on a voluntary basis in a few cases. Depending on the general goal of SEA, the number of compared scenarios and the chosen indicators, different assessment methods have been identified. Table 1 compares selected case studies with SEA in Waste Management, including our ‘‘Salzburg’’ case study. For details of the latter see Section 2. The case studies in Table 1 vary in some aspects. In the spatial dimension, two processes have been conducted on a national and four on a regional level. The waste types analysed vary only slightly: all case studies concentrate on municipal waste, industrial waste is not included, although it has a high impact on waste management systems. The number of alternatives varies from 3 to 8. A greater difference can be seen in the impact categories considered: all case studies include environmental effects (as mandatory for SEA), only 3 cases incorporate both environmental and economic and social effects. The largest differences can be seen with the assessment methods. The methods applied reach from verbal assessment to quantitative modelling, including weighting and aggregation. The specified impact categories range from single indicators like ‘‘BOD’’ or ‘‘Phosphorous Emissions’’ to high aggregated impact categories such as Global Warming Potential or Acidification. Additionally, the single indicators aggregated to impact categories also tend to vary.

2. Sea case study ‘‘Waste Management Plan Province of Salzburg’’ 2.1. Initial position In the province of Salzburg, a predominantly rural region in Austria with approximately 500,000 inhabitants, development of a new plan for municipal waste management was scheduled. This plan was required in order to determine the goals and implementation of waste management over the forthcoming decade. To enable a broad technical and public discussion, an SEA was started in January 2003. The possible consequences for the environment, society and economy needed to be taken into account during this process. An SEA can be applied to already formulate plans and programs as well as to plans and programmes in the preparatory phase. In the case of Salzburg, the SEA process was applied while the waste management plan was under development. Thus the Environmental Report from the SEA will serve as a basis in defining the waste management plan. 2.2. Procedure and participants With the use of a participatory process it should be ensured that different interests are used to build up synergies as well as partnerships and hence find sustainable solutions as a joint decision (Bu¨chl-Krammersta¨tter, 2003). Participation expands the programme information and should help to clarify and stabilise communication and power relationship between stakeholders. In view of the fact that the decision as to which stakeholders are to be included in the process, as well as

Table 1 Comprising overview of SEA in waste management Region

Waste types

Alternatives

Impacts

Assessment method

The Finnish Waste Management Plan (European Commission DG XI (EC), 1997) SEA to the Waste Management Plan of Pirkanmaa region (Finland) (Arbter, 2001)

Household waste

3

Socio-economic, environmental effects

Qualitative Expert-judgement, verbal argumentative

Residual waste

5

Ecological, economical, social effects

Munic. Waste haz. Waste, harbour sludge

3

Environmental, social effects

Quantitative (absolute figures) No weighting No aggregation Personal assessment by each participant Expert judgement

Municipal waste

5

Environmental effects

Municipal waste

7 (4 optimised)

Mainly impact on quality of life; ecological, economical and social effects

Municipal waste

8 (12 due to minor variations)

Ecological, economical and social effects

The 3rd Provincial Waste Management Plan Gelderland (European Commission DG XI (EC), 1997) SEA of the Dutch Ten Year Programme on Waste Management 1992e2002 (Arbter, 2001) Waste Management Plan Vienna (Umweltbundesamt, 2001)

Waste Management Plan Province of Salzburg (Koblmu¨ller et al., 2004)

Quantitative No weighting No aggregation Quantitative 5 load factors depending on the range to baseline scenario Weighting from expert interviews Aggregation between the objectives (i.e. Environment, economy and society) Quantitative; partly qualitative 3 load factors depending on the range to baseline scenario No weighting No aggregation

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the kind of participation involved, represent critical points (Kapoor, 2001) all relevant stakeholders in all decisionmaking phases were intended to be included with an equal say. For this purpose, only a rough structure of the process (sequence and contents of the workshops) was predisposed. For all major decisions (like the selection of criteria, etc.) a consensus was sought. Providing documents and background materials before and minutes after each workshop supported this. Within each of the workshops, a unanimous decision was aimed for, at least a majority decision had to be taken. The moderator was careful to hear the opinion of all participants. All the parties concerned (Table 2) and two expert teams were involved throughout the process. The authors as one of expert teams (with expertise in waste management) developed the waste management scenarios and calculated the main environmental effects, while the other expert team concentrated on assessment. Both expert teams were also members of the core group. After defining the work program of the process, all major decisions (e.g. framework, selection of criteria and scenarios) were agreed on in line with the opinion of the majority of the project team. The main tasks of the core group were to prepare the process, to prepare and guide the workshops and to prepare the Environmental Report. Tasks of the project group were to discuss and agree on the rules for the workshops, to discuss and agree on the chosen methodology and assessment criteria, to discuss preliminary results and to discuss and agree on the final results laid down in the Environmental Report. The aim of the process was to pinpoint the pros and cons of the different scenarios rather than to identify the ‘‘best solution’’. As described by Finnveden et al. (2003), an SEA may be applied to support a choice between two or more alternatives or to identify the critical aspects of possible alternatives. Here the latter was the case and the government of the province of Salzburg will take the final decision concerning the future strategy. The major steps in the process are shown in Fig. 1.

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10 years) and the spatial horizon (mainly the Province of Salzburg, waste treatment also outside this area) were established. The waste streams to be considered (municipal waste) or excluded from the analysis (industrial waste) were listed. 2.4. Developing scenarios and criteria In a second step methodologies for the definition and selection of scenarios and for the assessment criteria were defined. In order to build scenarios, the expert teams made the following proposal: for each waste stream (such as waste paper, biogenic waste, residual waste etc.), the different options were considered for collection, recycling and treatment. Fig. 2 illustrates an array showing four basic scenarios (1e4), supplemented by the baseline scenario 0, built by combining more or less recycling of recyclables (like waste paper or glass) with treatment options (MBP, MSWI) for waste types such as residual waste. After listing of the options for each of the waste streams by the expert teams, in close co-operation with the project team, final options were selected and assigned to the scenarios as a common decision of all parties. Thus, in this context, the term scenario is used to imply a combination of options for the single waste streams, including the effects on other waste streams. Accordingly, discussions in small groups proved to be a particularly useful method. Eight scenarios were ultimately developed (step 3). Additionally, a baseline scenario (Scenario 0) was defined to represent the status quo in recycling and waste treatment technology, but also included a prognosis for the waste quantities in 2012. The values calculated, based on a forecasting model (Beigl et al., 2003), were used for all scenarios. With regard to recycling, the current day recycling quotas were applied. 2.5. Scenarios The eight scenarios, which were developed and assessed in the process, are described in Table 3.

2.3. Scope In the first step the scope of the SEA was defined and both general rules and a code of behaviour for the following process were outlined. Definitions for the time (planning period of Table 2 Participants and their representation

2.6. Criteria In accordance with the environmental authorities and based on a decision taken by the project team in a workshop different Step 1: Scope, general ruels, code of behaviour

Organisation

No. of delegates

Core group

Project team

Provincial government Provincial administration Austrian Federal Ministry of Agriculture and Forestry, Environment and Water Management Expert teams (researchers) Federation of Austrian Industry Economic Chamber of Salzburg Chamber of Labour Environmental ombudsman Municipalities Moderator

1 7 2

x x x

x x x

8 1 1 1 1 7 1

x

x x x x x x x

Step 2: Developing scenarios and criteria

Step 3: Scenario formulation

Step 4: Criteria selection

Step 5: Assessment of the scenarios

Step 6: Discussion of the assessment results

Fig. 1. Major steps in the Salzburg case study.

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recycling

treatment

0

MBP

MSWI

more

1

2

less

3

4

baselinescenario

Fig. 2. General framework for scenarios. MSWI, municipal solid waste incinerator; MBP, mechanical biological pre-treatment (for details see Binner, 2002).

subjects of protection were determined (step 4). To identify the criteria and indicators relevant to the assessment, a comprehensive list of potential impacts subject to possible activation by means of a waste management measure and having some potential degree of impact on the defined subjects of protection was identified by the expert group. This list was illustrated to the project team and a decision was reached. The subjects of protection, as well as the possible environmental, social and economic impacts of different waste management procedures, were subsequently merged into a so-called ‘‘relevance matrix’’. For each array in this matrix, the relevance of the impact to the affected area of protection was screened. The arrays in which a real impact was detected on the subject of protection provided the building blocks for the rating matrix shown in Fig. 3. If available, quantitative indicators (such as GWP, AP, etc.) were used. In some cases it was necessary to resort to the application of qualitative indicators. Some of the indicators were used in more than one category. For example, the amount of residues from waste treatment processes influences both the category ‘‘environmental effects’’ and ‘‘social effects’’.

Table 4 shows the final criteria selected. With regard to environmental effects, the impact categories considered were mainly provided by LCA modelling (like HTP, EP, AP, GWP, etc.). Quantity and quality of residues from waste treatment processes were used as an indicator of the environmental effects of landfilling. Additional indicators such as traffic flow (from waste transport), hazardous incidents and land use (for collecting sites, treatment plants and landfills) were used on a qualitative basis. Indicators such as traffic flow could also be applied on a quantitative basis. However, previous research work carried out by our group, cf. Salhofer et al. (2003) and Wassermann (2003), showed that a somewhat detailed approach is required to model the traffic flow from waste transport. Regarding the available time and resources, traffic flow was reduced to a qualitative (non-quantified) indicator, whereby more recycling is related to more traffic and vice versa. To ascertain economic effects, we calculated cost effects for waste producers. Regional added value and synergy effects were included only as a qualitative aspect. Again, this was due to the time and financial restraints in the process. For the social effects, almost no additional quantitative indicators could be used. Typical criteriadodour, noise or user conveniencedwere described and assessed on a qualitative basis. Residues were used as indicator of landfill volume (influence on landscape) and autonomy (are adequate treatment facilities and landfills available in the region?). 2.7. Assessment Following identification of criteria, the expert teams carried out an assessment of the eight scenarios (step 5). For each array, a pair wise comparison was made with the baseline scenario. For the quantitative criteria, a range of 10% was considered neutral, while a larger difference was assessed as positive (þ) or negative (). For single criteria, which were considered as being extremely sensitive, lower threshold values were used. These cases were discussed and decided

Table 3 Scenarios and their main characteristics (simplified) Scenario 1a

1b

3a

3b

More Recycling þ MBP  high recycling rate (paper, biogenic waste, metals)  packaging: only plastic bottles and cans recycled  residual waste and non recyclables: treatment by MBP More Recycling þ MBP þ Deposit  as 1a, in addition a deposit for plastic bottles and cans is introduced, to achieve a high recycling rate More Recycling þ MSWI  high recycling rate (as 1a)  packaging: only plastic bottles and cans recycled  residual waste and non recyclables: treatment by MSWI More Rec. þ MSWI þ ‘‘Combustible Bag’’ þ Deposit  high recycling rate (as1a)  packaging: only plastic bottles and cans recycled  other plastic packaging and thermal material is collected separately (‘‘combustible bag’’) and processed thermally  residual waste and non recyclables: treatment by MSWI

Scenario 2a

2b

4a

4b

Less Recycling þ MBP þ Minimum Paper Recycling  low recycling rate  paper: only a minimum is recycled  residual waste and non recyclables: treatment by MBP Less Recycling þ MBP  low recycling rate (as 2a)  paper recycling in line with baseline scenario Less Recycling þ MSWI þ Minimum Paper Rec.  low recycling rate (as 2a)  paper: only a minimum is recycled  residual waste and non recyclables: treatment by MSWI Less Recycling þ MSWI  low recycling rate (as 2a)  paper recycling in line with baseline scenario

environment

human beings flora,fauna

Environment

society

eco

Resources Economy

Society

human health, well-being habitats, biodiversity Soil Water

+ +/+/+/-

Air Climate raw materials surface area waste producer national economy utilisation interests landscape and cultural heritage Autonomy job provision convenience local / regional practicability

+/-

+/-

+ +

costs

615

sensitivity of WMS

utilisation of resources

traffic

residues

Factors/Objectives

noise

air pollution

impact of waste management measures

liquid pollutant emission

S. Salhofer et al. / Environmental Modelling & Software 22 (2007) 610e618

+/+/-

+/+/-

-

+ +

+/+/+/-

+/+ +/+/-

+/-

+/+/-

+/+/-

+/+/+/+/-

+

+/+/+/-

+/-

+

+ +

Fig. 3. Example of the rating matrix for one specific scenario (simplified). WMS, waste management system.

on by the project team. For the qualitative criteria, a comparison was made with the baseline scenario based on arguments documented in the Environmental Report (Koblmu¨ller et al., 2004). No further aggregation or weighting was done. The results of assessment were displayed in a rating matrix for each scenario as shown in Fig. 3. This allows the user to recognise the advantages and disadvantages of each scenario without expressing a preference for one scenario as the best or worst solution. A description of the process, the assumptions made, the scenarios and the assessment results were documented in the Environmental Report. To conclude the drawing up of the Environmental Report, comments provided by participants in the process will be taken into consideration and subsequently the final Environmental Report will be published. It is intended that governmental authorities will utilise the Environmental Report as a basis through which to formulate a definitive waste management plan. 2.8. Results Fig. 3 illustrates the representation of results for one of the scenarios. In this case, positive effects (advantages) were obtained with traffic and costs, and partly with air pollution. Negative effects (disadvantages) for air and climate were observed in the presence of air pollutants, and negative health effects from liquid pollutant emissions as well as negative effects on the national economy. Other fields of impact were characterised by a neutral effect. 3. Critical points During the process several critical points were evidenced; these will be discussed in the following paragraphs.

3.1. Selection of criteria With the selection of criteria, two critical points must be mentioned: the acceptance of the selection and the type of criteria. As the comparison of SEA case studies (Section 1.3) showed, impact categories anddrelated to thatdcriteria may vary largely from case to case. This is related to the specific questions to be answered as well as the assessment method applied. The choice of criteria should be acceptable to all participants, cf. Balcomb and Curtner (2000). In our case, the criteria were discussed and agreed in step 4. In this workshop, the participants did not pay too much attention to the selection. In a later phase, when results were discussed, some participants returned to the selection of criteria and questioned some of the latter. Although formally correct (the choice was discussed, laid down in the minutes of the meeting, which was agreed in the next meeting), the choice had to be

Table 4 Selected criteria by category (simplified) Category

Quantitative criteria

Qualitative criteria

Environmental effects

HTP, TETP, AETP, AP, EP, POCP, GWP, residues Cost effects for waste producers

Traffic flow, hazardous incidents, land use

Economic effects

Social effects

Residues, cost for waste producers

Regional added value, synergy effects (treatment sites) Appearance, traffic flow, regional jobs provided, odour, noise, convenience, autonomy

HTP, human toxicity potential; TETP, terrestrial ecotoxicity potential; AETP, aquatic ecotoxicity potential; AP, acidification potential; EP, eutrophication potential; POCP, photochemical ozone creation potentials; GWP, greenhouse warming potential.

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adapted in this later stage. To avoid these problems, a more detailed analysis of the participants’ preferences could be done in an early stage of the process. A case study where such an analysis of the stakeholders perceptions was undertaken as part of the process is reported by de Marchi et al. (2000). At this point, before going on to the multicriteria decision tool, an ‘‘institutional analysis’’ was performed, including participant observation, interviews with local actors and a survey on a random sample of residents. Concerning the type of criteria, the chosen set of criteria can be classified according to their degree of quantification. In detail these are:  quantitative criteria such as HTP, GWP etc., as generally used in LCA modelling  qualitative, albeit figure-based criteria, such as waste transportation-related traffic, noise or job effects and  qualitative, non figure-based criteria, such as synergy effects, autonomy and availability of facilities. Additionally, the criteria vary in their site specifics and spatial dimension:  local effects are covered by criteria such as land use, noise, residues, regional added value, regional job provision etc. while  global effects are covered by GWP, HTP, AP etc. As illustrated in the above list, qualitative criteria were used mainly to assess local effects, while quantitative indicators were used in the case of global effects. The main reason for the latter is the choice of an LCA model for the quantitative indicators, which commonly address to a greater degree the global effects. For the qualitative indicators, local conditions were adequate to a large extent, although at the same time the analysis performed paid little attention to detail. For example, odour and noise were contemplated merely at the basis of a simple classification (more composting triggers more odour, more recycling causes more noise etc.) Briefly, the selection of the indicators used reflects the conflicting approaches of parties involved in the process. While the members of the expert teams were more interested in scientifically acknowledged indicators, the other participants (industry, municipalities.) placed greater emphasis on criteria that reflected current discussions taking place in society (e.g. traffic problems) and were more relevant to regional politics. As mentioned above, an additional step of prior assessment of the stakeholder’s perception may help to establish a more homogeneous and broadly accepted set of criteria. 3.2. Weighting and aggregation In the Salzburg case study, no further aggregation of criteria was made. This decision was influenced by the aim of the SEA process, to identify critical aspects of the scenarios rather than to identify one ‘‘best solution’’. In other cases of SEA in waste management, like the Waste management Plan Vienna,

a weighting and aggregation was done. There are numerous possibilities for multi-criteria weighting within the single categories as well as between categories, such as normalisation, ABC-Method, AHP-Method, CBA and others (Saaty, 1980; Roy, 1991; Al-Kloub et al., 1996). Aggregation methods for environmental effects in LCA modelling are well acknowledged and two approaches can be distinguished: the problem-oriented approach, cf. Guinee et al. (2001) and the damage-oriented methods, cf. Goedkoop et al. (2000). Damage-oriented methods allow an aggregation between impact categories in terms of common factors. Problem-oriented methods such as CML aim to simplify the complexity of hundreds of mass flows into a few environmental areas of interest. In the latter case aggregation of results is obtained by means of normalisation, or of other approaches such as the Swiss Eco-factors 1997 (BUWAL, 1998) where aggregation to one single value is enabled. More formal approaches to aggregate environmental impacts using Rough Sets theory or symmetric fuzzy linear programming have been described by Tan (2005a,b). With regard to economic effects, although a macroeconomic approach is feasible, several practical obstacles are encountered, e.g. the regional breakdown of data, estimation of the regional effects of investments etc. For social criteria, aggregation of criteria can be obtained by means of methods such as value benefit analysis or multi criteria assessment approaches (Noble, 2004). Environmental and economic effects can be integrated with a Cost Benefit Analysis. However, limitations to the latter include the difficulty of estimating the monetary value of the environmental impacts, which may lead to an overestimation of economic effects and an underestimation of environmental effects, cf. Fatta and Moll (2003). In multi-criteria analysis, environmental, economic and social criteria can be integrated. Aggregation can be undertaken by several methods, (Saaty, 1980; Roy, 1991), including advanced methods to include fuzzy sets in a new MCDA approach, called NAIADE (Novel Approach to Imprecise Assessment and Decision Environments), cf. Munda et al. (1995). 3.3. Result representation and interpretation Subsequent to assessment of the scenarios, the results obtained should be interpreted and represented in a non-technical self-explanatory form. Especially in our case, where a mixture of quantitative and qualitative assessment methods was chosen, problems occurred during this step. It was decided to provide the results of the analysis in the qualitative way shown in Fig. 2. In the case of qualitative indicators this was quite easy. However, for the quantitative indicators the classification of the results into ‘‘positive’’, ‘‘neutral’’ and ‘‘negative’’ compared with the baseline scenario represented a critical issue. This part of the evaluation involved the forming of a judgement as to whether or not a predicted effect would assume environmental significance. In spite of the availability of various methods with which to solve this problem (such as normalisation), we opted to use

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threshold values. The type of method chosen implied that the relative differences between scenarios could be rather large, while the identification of absolute effects was somewhat lacking. This led to discussions as to the height of the threshold values within the project group. The relative importance and magnitude of the results for each system in comparison to a reference system could provide more robust results, although ultimately it would not be as self-explanatory and would require additional time and effort. 3.4. Participation and time frame As described in Section 2.1, attention was paid to include all participants into the process. Despite this arrangement, some of the participants took much more advantage of the opportunity to express their opinion than others. This and the observation that the participants influenced the results by changing the criteria in a late stage lead to the conclusion that the participation should take place in a more structured way. Experts from the social sciences could be helpful in this context as our project team was mainly technically orientated. Another obstacle was the short timeframe of the process, which was limited to 12 months and did not allow additional steps. 4. Conclusions Comparing the ‘‘Salzburg’’ case study with other SEA processes or other participatory processes, a major difference was shown in the degree of aggregation of the criteria and results. In our case the design of the process was oriented to identify pros and cons of alternatives, without finding a ‘‘best solution’’. As a disadvantage of this approach, a large number of single results was obtained. This made it harder to interpret the results and at the end of the process it was not quite clear which (political) consequences would be drawn from the results. As a positive aspect of this approach, we assume that the participants were more highly motivated to take part in a ‘‘simple’’ process without a complex methodology. They were not forced to understand a methodology and to express their preferences, as necessary for a step of weighting and aggregation. At the end of the process, all participants expressed their satisfaction with the clear and short process. Considering the assessment process and the set of criteria, a certain unbalance resulted from the application of more complex, numerical modelling (LCA for environmental effects) and a qualitative assessment for other areas. For this type of process, it may be sufficient to rely on qualitative criteria. If the intention of the process is the identification of a ‘‘best solution’’, a higher aggregation of results is necessary. This would imply the following:  to identify the participants preferences at an early stage, including methods like the ‘‘institutional analysis’’, observation, interviews and surveys (De Marchi et al., 2000);  to apply appropriate methods for the aggregation of quantitative and qualitative criteria (like NAIADE);

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