FREIE UNIVERSITÄT BERLIN, ENVIRONMENTAL POLICY RESEARCH CENTRE [FFU]

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1 FREIE UNIVERSITÄT BERLIN, ENVIRONMENTAL POLICY RESEARCH CENTRE [FFU] and JAPANESE-GERMAN CENTER BERLIN [JDZB] Symposium Indicators for Evaluating Sustainable Development The Ecological Dimension from Monday, November 1 to Tuesday, November 2, 2004 at the JDZB, Saargemünder Str. 2, Berlin Substances and their (final) Sinks - a New Indicator for Monitoring Sustainability Dr. Gernot DÖBERL (Vienna University of Technology, Institute for Water Quality and Waste Management) / Prof. Dr. Paul H. BRUNNER (Vienna University of Technology, Institute for Water Quality and Waste Management) g.doeberl@iwa.tuwien.ac.at

2 Substances and their (final) sinks a new indicator for monitoring sustainability Gernot Döberl & Paul H. Brunner Institute for Water Quality, Resources and Waste Management Vienna University of Technology The need for sinks, where materials can be disposed of in an appropriate way, i. e. without endangering the environment, was realized by Abel Wolman already in the end of the 1960ies (Wolman, 1968). He pointed out that, without having appropriate sinks, once the environmental system could become overloaded by the output of anthropogenic activities. In this paper a final (ultimate) sink for a certain substance is defined as a place in the environment, where the substance remains for long-term periods (at least millenniums). The importance of final sinks is demonstrated with four examples two of which starting from waste management and leading to extended perception and two others in a more regional environmental context. THE IMPORTANCE OF (FINAL) SINKS Example 1 Where s the sink for zinc? Figure 1 shows a zinc balance of a galvanization process. Since the amount of wasted zinc is quite low, this process seems to be sustainable from a waste management s point of view (which, of course, is true compared to similar processes). If we look for potential sinks for the zinc flows, on the one hand landfills (maybe after some recycling loops) can be identified as sinks for the wasted zinc. On the other hand the product itself serves as a temporal sink for zinc. But what happens to the zinc in the product in a long-term perspective? Galvanization is used to protect surfaces, mostly steel surfaces, from being corroded. By doing so, the zinc itself will be corroded and dissipated in the environment, i. e. no distinct final sink can be identified. Diffusive or dispersive emissions are not restricted to zinc. In Figure 2 the amount of heavy metal emissions from consumption (which mostly are diffusive emissions) are compared to classical emissions occurring when producing goods. Due to the very efficient end-of-pipe technology, the emissions from production significantly decreased during the last centuries. At the same time emissions from consumption processes got more and more important (see the zinc example). In many cases it is not possible to quantify these dispersive emissions and in many of them would be below conventional emission standards. In case of heavy metals often a temporal (or final) sink exists (e. g. soils or lake s), where an accumulation during long-term periods can be observed, and thus a potential harm for the environment can be expected. 1

3 [ % ] Product 85 Sink:??? Zinc 99 Zinc-balance of a galvanization Zamak 0,6 Fluxing agent 0,4 Zn-pickle 3,1 Zn-ash + waste 7,6 Hard zinc 4,3 Sink: Landfill (Recycling) W. Enöckl, 1994 Figure 1: Zinc flows of a galvanization process 40 Emissions from production 30 tons / year Emissions from consumption Bergbäck, 1992 Figure 2: Heavy metal emissions from consumption and production in Sweden Example 2 On the Search for a final cadmium-sink Similar to emissions from production, the off-gas emissions of MSW incinerators significantly decreased during the last centuries due to the high standard of end-of-pipe technologies (Figure 3). But where are all these substances, where for example is the cadmium? First, the composition of waste changed since the 1970ies. Cadmium was partly banned from being used as a stabilizer in PVC etc. And secondly, cadmium (an atmophilic metal) is enriched in the residues of the flue-gas cleaning (so-called filter ashes). More than 90 % of the Cd-input is transferred into the filter ash during incineration (Figure 4). 2

1000 Changes since 1930 in % 100 10 1 0,1 0,01 0,001 NO x SO x HCl Hg Dioxine Cd Pb PM Emissions 1930 (=100 %) 1970 1995 Figure 3: Comparison of off-gas emissions from MSW incinerators in 1930, 1970

4 1000 Changes since 1930 in % ,1 0,01 0,001 NO x SO x HCl Hg Dioxine Cd Pb PM Emissions 1930 (=100 %) Figure 3: Comparison of off-gas emissions from MSW incinerators in 1930, 1970 and 1995 <1 % off-gas MSW 100 % (10 mg/kg) Cadmium 92+2 % filter ash (100-1,000 mg/kg) 8+2 % bottom ash <1 % sewage <1 % filter-cake Figure 4: Cadmium flows through a MSW incinerator (Schachermayer et al., 1995) Mostly, theses filter ashes are landfilled after a mechanical and chemical stabilization with cement (Figure 5) Figure 5: Landfill for cement stabilized MSW-incineration filter ashes (Wissenbüel, Switzerland) 3

5 % discharged [g Cd/100g Cd] A 05 Cadmium A 5 1 B A 52 B B ph Figure 6: Landfill Immobilization of cadmium in MSW-incineration filter ashes Many studies showed that cadmium becomes immobile during the landfilling process due to a ph-increase and to the formation of certain mineral phases working as a kind of long-term trap for many heavy metals. So, did we solve the Cd-problem? - For the recent generation? yes - For the next 10 generations? most probably - For the next 100 generations?? - Is the landfill a final sink for Cd?? Let s look back 100 generations (about 2,000 3,000 years): Time: Bronze Age (800 B.C.) Location: The Austrian Alps near Kitzbühel In this area an intensive copper-mining activity is documented at that time. Bronze-age miners left behind a lot of tailings consisting of gangue and smelting slags (Figure 7). In their mineralogical composition the slags are similar to modern products from thermal processes and they contain high concentrations of different metals. Nearly 3,000 years after their deposition they are a source for significant emissions caused by leaching of heavy metals. Hence, the tailings (representing a prehistoric type of landfill) are not a final sink for heavy metals and from a today s point of view the waste management system of bronze-age miners was insufficient and not sustainable because future generations had been endangered. This example impressively shows that long-term periods (millenniums) have to be taken into account when locating or assessing final sinks. Nevertheless, filter ashes probably come close to an appropriate final sink for cadmium. 4

6 800 B.C.: smelting slags containing Cu, Pb, Zn, Ag, Hg, Sb etc. Preuschen & Pittioni (1937) 2004 A.D.: heavy metal emission Figure 7: Bronze-aged tailings containing smelting slags in a former copper mining area near Kitzbühel (Eastern Alps, Austria) The importance of waste management for the anthropogenic cadmium household can be deduced from Figure 8. About 45 % of the total national cadmium flow is contained in combustible waste. Therefore, from an environmental point of view, a proper waste management system is essential to minimize the environmental impact of cadmium. But also from a resource management point of view this figure is interesting. If all combustible waste would be incinerated, about 90 % (see Figure 4) of the cadmium (i. e. about 40 % of the total national flow) would be transferred into the incineration filter ash. Hence, filter ash landfills (or man-made final sinks in general) can be seen as potential future sources for some raw materials as well [%] C Cl Zn Cd Hg Pb Energy Data: Morf, 1998 (substances); ÖSTAT, 1999; Baumeler et al., 1998 (energy) Figure 8: Flows of substances and energy in combustible waste (in proportion to total Austrian flows) So far, following conclusions can be drawn: 1. Final sinks are long-term traps for (harmful) substances 2. In some cases final sinks can be seen as potential future sources for raw materials 5

7 Example 3 Soils as (final) sinks Contrary to the atmosphere and the hydrosphere, soils often serve as (final) sinks for many substances. In Figure 9 the residence time of selected substances in a specific type of soil was assessed experimentally. For some substances, like PCB, Cu, DDT and Zn, this soil is a final sink. For all the others the soil is only a temporal sink. years Zn DDT Cu PCB 10 1 N K Atrazin P Salomons (1995) Figure 9: Residence time of different substances in a specific soil This situation directly leads to Figure 10: Until the 1970ies the environmental stress originated from production processes, traffic etc. Atmosphere and hydrosphere acted as somewhat like conveyer-belt carrying e. g. metals in soils and s. For some substances these soils and s will be final sinks, for some they will be long-term temporal sinks, and for all the others they were only short-term sinks. As mentioned before, the application of end-of-pipe technologies significantly improved the environmental situation during the last decades, so that recently (in some cases) the direction of emissions has been reversed; for those substances, soils and s have not been long-term temporal sinks, they are now emitted into the hydrosphere. until 1970 since 1980 Soil River Groundwater Air Estuarine River Soil River Groundwater Air Estuarine River s Rain Sea water Marine s Rain Sea water Marine Ocan Ocan Salomons (1995) Figure 10: The Response of soils 6

8 Other well known examples for a similar situation are old waste dumps or contaminated sites, now endangering the groundwater. Example 4 Oceans as (final) sinks 1 The Black Sea is a very important sink for about 25 countries and nearly 190 million people living in its catchment area. Its volume is about 550,000 km³ and there is only a small water exchange with the Mediterranean Sea. It comes close to an inland-lake and therefore it is a final sink for many substances, especially for those being transported by large rivers, like Danube or Dnepr. One of these substances is chloride, which is chemically very mobile, not toxic, but most organisms are very sensitive even to small changes in the salinity, which chloride ions are an important part of. Large oceans definitely are appropriate sinks for chloride emissions, but is this true for a rather small inland-lake as well? Catchment area: 2,300,000 km² Volume: 550,000 km³ Population: 190 millions Figure 11: Oceans as final sinks the example Black Sea (light: catchment area of River Danube) Figure 12 shows the results of a very rough assessment to evaluate if the Black Sea is an appropriate final sink for the long-term chloride emissions from its catchment area. Under the assumption that the whole volume is available as dilution potential, the yearly concentration increase is very small. Even after thousands of years this increase will not significantly change the salinity of the Black Sea. However, there are a lot of substances, e. g. some nutrients, the Black Sea is not an appropriate sink for. 1 This example is based on an exercise engineering students have to deal with in the lecture Urban Substance Household given at the Vienna University of Technology. More detailed information is available in Döberl & Brunner (2001). 7

Salinity: 20 (10 g Cl/l) Cl-Input: 400 kg / (cap*a) Conc. Increase: 0.

9 Salinity: 20 (10 g Cl/l) Cl-Input: 400 kg / (cap*a) Conc. Increase: g Cl / (l*a) Figure 12: The Black Sea as an appropriate final sink for chloride emissions An example for an inappropriate sink for chloride emissions is shown in Figure 13. If River Danube would be redirected into Lake Neusiedl, a fresh-water lake near Vienna, and if only the Austrian chloride emissions are taken into account, the salinity will be doubled up already after one year. This would cause irreparable damage to the lake s ecosystem. Redirecting River Danube Lake Neusiedl Volume: 0,3 km³ Salinity: 1-2 g/l Increase in concentration after 1 year (only Cl from Austria): > 1 g/l Figure 13: Lake Neusiedl as a final sink for the Austrian chloride emissions an example for an inappropriate sink Summing up the examples following final conclusions can be drawn: 1. Final sinks sometimes are the limiting factor for anthropogenic substance flows, e.g.: - soils for some heavy metals - lakes for chloride - atmosphere for CFC 2. Thus, we think the final-sink-problem should be considered when monitoring sustainability 3. Research is needed to identify (appropriate) final sinks for some indicator-substances 4. For some substances there is no final sink available. In these cases appropriate targetprocesses should be identified Lastly, we would like to propose a first, very simple indicator: Amount of substances a region/process directs in appropriate final sinks Total amount of substances emitted by a region/process 8

10 REFERENCES Baccini, P. & Brunner, P. H. (1991): Metabolism of the Anthroposphere. Berlin etc., Springer. Baumeler, A., Brunner, P.H., Fehringer, R., Kisliakova, A. & Schachermayer, E. (1998): Reduktion von Treibhausgasen durch Optimierung der Abfallwirtschaft. Verband der Elektrizitätswerke Österreichs (ed.), Wien. Bergbäck, B Industrial Metabolism: The Emerging Landscape of Heavy Metal Emissions in Sweden, PhD Thesis, Linköping University, Sweden. Döberl, G. & Brunner, P.H. (2001): Geeignete letzte Senken und Endlager als zentrales Ziel einer nachhaltigen Abfallwirtschaft. SIDAF-Schriftenreihe, 8, , Freiberg/Sachsen. Morf, L.S. (1998): Entwicklung einer effizienten Methode zur kontinuierlichen Bestimmung von Stoffflüssen durch eine Müllverbrennungsanlage. Dissertation, TU Wien. Preuschen, E. & Pittioni, R. (1937): Untersuchungen im Bergbaugebiete Kelchalpe bei Kitzbühel, Tirol. Mitteilungen der Prähistorischen Kommission der Akademie der Wissenschaften, III. Band, Nr. 1-3, Wien, Hölder-Pichler-Tempsky A. G. Salomons, W. (1995): Long-term strategies for handling contaminated sites and large-scale areas. In Salomons, W. & Stigliani, W.M. (eds.): Biogeodynamics of Pollutants in soils and s. 1-30, Springer, Berlin etc. Schachermayer, E., Bauer, G., Ritter, E. & Brunner, P.H. (1995): Messung der Güter- und Stoffbilanz der Müllverbrennungsanlage Spittelau. Umweltbundesamt Monographien, 56, Wien. Wolman, A. (1968): The Metabolism of Cities. In: Cities: A Scientific American Book, Knopf, New York, Contact Dr. Gernot Döberl, Prof. Dr. Paul H. Brunner Institute for Water Quality, Resources and Waste Management Vienna University of Technology Karlsplatz 13/E226 A-1040 Vienna Austria g.doeberl@iwa.tuwien.ac.at 9

Thermal Treatment an Essential Element of Sustainable Waste Management. Paul H. Brunner Vienna University of Technology

Thermal Treatment an Essential Element of Sustainable Waste Management Paul H. Brunner Vienna University of Technology www.iwa.tuwien.ac.at The beginning Paul H. Brunner, TU Vienna 2/24 and not the end