4 Material und Umwelt
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- 4.3 Schadstofftransfer und Umwelttechnologien (43) (entfernen)
Eingeladener Vortrag
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Derzeit gibt es intensive Diskussionen über die Entlassung von Deponien aus der Nachsorgephase. Die Deponie müsste dafür nach der Deponieverordnung (DepV) u. a. „insgesamt dauerhaft standsicher" sein. Geokunststoffe erfüllten ihre Funktion über einen Zeitrahmen von lediglich mindestens hundert Jahren. Dies stehe somit im Widerspruch wird argumentiert. Das neue LANUV-Arbeitsblatt 33 schließt daher im Moment eine Entlassung aus der Nachsorge von Deponien faktisch aus, wenn in den Böschungen Geokunststoffprodukte eingesetzt wurden. Auch der Fachbeirat der BAM zur Zulassung von Geokunststoffen, Polymeren und Dichtungskontrollsystemen hat sich daher mit der Thematik beschäftigt. Die aktuelle Situation soll daher auf dieser Grundlage diskutiert werden.
Im Beitrag wurden Ergebnisse von Elutionsuntersuchungen mit PFC kontaminierten Bodenmaterialien vorgestellt. Zum einen waren das Untersuchungen zur Eignung von Säulenversuchen für diese Schadstoffgruppe und zum anderen vergleichende Schüttel- und Säulenversuche für zwei verschiedene Böden mit unterschiedlichen PFC-Kontaminationsquellen.
Im Beitrag wurden erste Ergebnisse eines laufenden UFOPLAN-Vorhabens zu den neuen Kriterien der Verwertungsmöglichkeiten von Bodenmaterialien außerhalb der durchwurzelbaren Bodenschicht nach den §§ 6 bis 8 der Novelle der BBodSchV vorgestellt. Der Schwerpunkt lag auf Untersuchungen der Schadstoffgruppe der PAK. Dabei wurden Probleme der Vergleichbarkeit und Leistungsfähigkeit verschiedener Elutions- und Analyseverfahren der PAK-Analytik diskutiert.
Wie Länder mit ihren Abfällen umgehen, hängt nicht nur von der Wirtschaftskraft eines Landes ab. Selbst in einem reichen Land wie Australien werden unbehandelte Abfälle einfach deponiert. Im Rahmen der Travelling Conference, einer vom Bundesministerium für Bildung und Forschung (BMBF) geförderten Vortragsreihe, besuchten Fachleute die Länder Südkorea, Vietnam und Australien, um mit Experten vor Ort Fragestellungen aus der Abfallwirtschaft zu diskutieren. Zu den Schwerpunktthemen zählte die Steigerung der Ressourceneffizienz im Spannungsfeld von ökonomischen und umweltpolitischen Interessen. Eine Frage war beispielsweise die Bewertung der Umweltverträglichkeit von mineralischen Abfällen, wenn diese als Ersatzbaustoffe eingesetzt werden. In diesem Beitrag werden Ähnlichkeiten und Unterschiede bei der Entsorgung von Siedlungsabfällen, beim Recycling und bei der Bewertung der Umweltverträglichkeit der Wiederverwertung von Abfällen in den drei besuchten Ländern im Vergleich zu Deutschland aufgezeigt. Dabei ist man sich in Deutschland und den drei besuchten Ländern einig, dass die Abfallbeseitigung auf Deponien ohne Rückgewinnung von Ressourcen oder Energie die schlechteste Abfallentsorgungsoption ist. Einigkeit besteht auch darin, dass die Ziele einer nachhaltigen Abfallwirtschaft der Schutz der menschlichen Gesundheit und der Umwelt sowie die Schonung von Ressourcen sind. In allen drei Ländern werden große Mengen an mineralischen Abfällen erzeugt, die bei Nachweis der Umweltverträglichkeit einen Teil von natürlichem Sand und Kies für die Bauindustrie ersetzen könnten. Ähnlich wie in Deutschland werden recycelte Abfälle im Tiefbau jedoch nur in geringem Maße eingesetzt. Gründe dafür sind fehlende Behandlungsanlagen für mineralische Abfälle und Bedenken im Hinblick auf die Umweltverträglichkeit.
Transformation of carbendazim, diuron, octylisothiazolinone and terbutryn was investigated in two paints containing either white titanium dioxide or a red iron oxide pigment.
Test specimens of these coatings on glass were exposed to water contact and UVA-radiation under laboratory conditions. Panels of birch plywood were coated and exposed to natural weather conditions in a field experiment. Concentrations of biocides and transformation products were analysed in leachates from laboratory tests, runoff samples and remaining coatings. Water contact, UVA radiation as well as pigments in the paints affected the pattern and amount of transformation products.
Tools for the characterization of secondary raw materials - status of leaching test application
(2018)
Leaching tests are used as tools for the assessment of environmental compatibility of granular waste materials with potential for reuse. The presentation gives an overview on available leaching tests, their field of application and relation to legislation. Furthermore robustness testing to elaborate optimized test conditions as well as performance characteristics from validation studies by BAM are addressed.
Tools for the characterization of secondary raw materials - status of leaching test application
(2018)
Leaching tests are used as tools for the assessment of environmental compatibility of granular waste materials with potential for reuse. The presentation gives an overview on available leaching tests, their field of application and relation to legislation. Furthermore robustness testing to elaborate optimized test conditions as well as performance characteristics from validation studies by BAM are addressed.
Tools for the characterization of secondary raw materials - status of leaching test application
(2018)
Leaching tests are used as tools for the assessment of environmental compatibility of granular waste materials with potential for reuse. The presentation gives an overview on available leaching tests, their field of application and relation to legislation. Furthermore robustness testing to elaborate optimized test conditions as well as performance characteristics from validation studies by BAM are addressed.
An approach to achieve “zero leakage” is discussed with respect to the experience in Germany, where strict regulations for landfill lining and capping systems have been developed and issued because of large environmental problems related to landfills that accumulated in the 1970’s and 1980’s. These regulations for landfills and geosynthetics which are used in landfill liner and capping systems are shortly described. The main certification requirements for the products as well as conclusions for their use are presented. Using a thick, high quality HDPE geomembrane (GMB), which is installed free of residual waves and wrinkles in intimate contact with a compacted clay liner (CCL) or geosynthetic clay liner (GCL) of very low permeability, by a qualified, experienced, well equipped and properly third‐party controlled installer and which are protected by heavy protection layers designed with respect to long‐term performance of the GMB, may result in a liner or capping system of practically no leakage. This is demonstrated by analyzing results of measurements obtained from permanently installed leak detection systems in combination with HDPE GMBs.
An approach to achieve “zero leakage” is discussed with respect to the experience in Germany, where strict regulations for landfill lining and capping systems have been developed and issued because of large environmental problems related to landfills that accumulated in the 1970’s and 1980’s. These regulations for landfills and geosynthetics which are used in landfill liner and capping systems are shortly described. The main certification requirements for the products as well as conclusions for their use are presented. Using a thick, high quality HDPE geomembrane (GMB), which is installed free of residual waves and wrinkles in intimate contact with a compacted clay liner (CCL) or geosynthetic clay liner (GCL) of very low permeability, by a qualified, experienced, well equipped and properly third‐party controlled installer and which are protected by heavy protection layers designed with respect to long‐term performance of the GMB, may result in a liner or capping system of practically no leakage. This is demonstrated by analyzing results of measurements obtained from permanently installed leak detection systems in combination with HDPE GMBs.
The production of secondary materials from waste materials requires, in most cases, significantly lower energy amounts than the primary material production of raw materials. Along with lower energy demand, the greenhouse gas emissions produced are also lower. The duty of a modern waste management system should therefore be to collect and sort the waste materials in a way that the highest amounts of single material fractions with the highest qualities can be generated. In this contribution, the greenhouse gas balances of the theoretical treatment of the household waste, if collected as mixed waste in sanitary landfills, in waste incineration plants, or in mechanical-biological treatment plants, are compared to the existing separate waste collection and treatment in Germany in 2014. The results show that the treatment of the mixed collected household waste in sanitary landfills would lead to a significant release of greenhouse gases. The treatment in MBTs with the recovery of valuables and the further disposal of the biologically stabilized fraction on landfills, as well as the treatment of the high calorific fraction (also called refuse derived fuel – RDF) in RDF plants, coal-fired power plants, or cement kilns, would lead to small amounts of avoided greenhouse gas emissions. The thermal treatment in waste incineration plants would lead to moderate amounts of avoided greenhouse gases. Only with the actually practiced separate collection and treatment of household waste were significant amounts of greenhouse gas emissions avoided. In total, this is approximately 5.5 million tons of carbon dioxide equivalents for approximately 45.5 million tons of separate collected and treated household waste in Germany in 2014.
Direct and indirect effects (DIERec) of the recovery of secondary resources are in the range of 500 million tons per year in Germany; energy savings are 1.4 million TJ. These savings are between 10 and 20% of the total. The effects of materials recovery exceed those of energy recovery by far except for secondary plastic material, where DIERec from energy recovery is higher by factor of 2.7. Untapped potential for the recovery of secondary resources exists in the fine fraction of bottom ash from municipal solid waste incineration, mainly Cu and precious metals, and in urban mining.
Waste-to-energy (WtE) is one of the leading technologies for municipal solid waste (MSW) treatment in Europe. According to Eurostat data, in 2015, 27 % of MSW was utilized in WtE plants, which represents more than 80 million tons per year. Therefore, the European annual production of incineration bottom ash (IBA) is about 20 million tons, as it is about 25 wt% of input MSW. In the European List of Waste, IBA is listed as mirror entry (i.e. waste materials which should be classified as either non-hazardous or hazardous, depending on its hazardous properties and/or content of hazardous substances) under codes 19 01 11 and 19 01 12.
Recent trends indicate that WtE allows, apart from utilization of the energy content of waste, also the recovery of various valuable components. Hence, WtE can be included in the key technologies that can put the circular economy concept into practice. Secondary raw materials in the case of WtE are solid residues, especially IBA, as it is a secondary source, particularly of ferrous metals (Fe) and non-ferrous metals (NF) and glass. Moreover, the residual mineral fraction can be used for various applications in the construction industry, i.e. as aggregates substitute for bound or unbound applications, in cement manufacturing or, as indicated by recent research, also in more sophisticated applications, e.g. for ceramics production. Recovery of these metals can also cause huge greenhouse gas savings. Alone in Europe, metal recovery from IBA reduces greenhouse gas emissions by approximately 3.2 million tonnes of CO2 equivalent.
The production of secondary materials from waste materials requires, in most cases, significantly lower energy amounts than the primary material production of raw materials. Along with lower energy demand, the greenhouse gas emissions produced are also lower. The duty of a modern waste management system should therefore be to collect and sort the waste materials in a way that the highest amounts of single material fractions with the highest qualities can be generated. In this contribution, the greenhouse gas balances of the theoretical treatment of the household waste, if collected as mixed waste in sanitary landfills, in waste incineration plants, or in mechanical-biological treatment plants, are compared to the existing separate waste collection and treatment in Germany in 2014.
Small grain size fractions of municipal solid waste incineration (MSWI) bottom ash (BA) contain elemental and chemically bonded metals in appreciable amounts, especially copper. Investigations with a centrifugal concentrator were carried out using samples, which had been treated with different impact devices. Partly the impacts of single devices were visible in outlines, but mostly the surfaces of the metals were still covered with mineral residues. To generate copper rich fractions, parameters of the separation process should ensure mass yields <2%, best between 0.5 and 1%. The density of the concentrates is then generally >3.2 g/cm3. Best results were achieved with material from a special treatment train which is adapted to grain sizes <2 mm. Reliable copper contents between 20 and 40% (single runs >50%) could be realised.
However, considering the required mass yields, referred to this subset only 150–170 g copper would be recovered from 1 Mg MSWI BA. Furthermore, this copper is only in parts present in elemental form. A
dependable added value of such treatment step seems to be given only, if that enables a recycling of the mineral aggregates (tailings) in parallel to avoid landfill costs.
Potential use of incineration bottom ash in construction – Evaluation of environmental impact
(2018)
Around 5 million tonnes of MSWI bottom ash (BA) are generated per year in Germany. The incineration itself serves for metals as a concentrating and cleaning process. However, due to the almost exclusive wet extraction out of the furnace chamber the various metals are integrated in a heterogeneous and instable matrix. The metal recovery is therefore still a challenge relating the recovery rate and the purity, respectively. With state of the art treatment trains in Germany around 7.7% of ferrous metals and 1.3% of non-ferrous metals can be recovered out of MSWI BA. Large quantities of the mineral fraction are reused for sub-base material in road construction. A three month ageing period has been established as the common practice of further treatment of bottom ash before reuse applications. In the course of this aging the pH value of bottom ash decreases and contaminants are immobilized by processes like carbonation, hydration and oxidation. In particular leaching of heavy metals may be reduced to environmentally acceptable levels. However, the aging results in fixing of other valuable resources such as metals. Two laboratory scale lysimeters (30 cm in diameter) are being operated for more than three years aiming at the investigation of the long-term leaching behavior of a 0.25/45 mm mineral material obtained by treatment of MSWI bottom ash directly after incineration by a wet processing technology. Artificial rainwater is used as leachant (pH ≈ 6, ingredients NO32-, Cl-, SO42-, Na+, K+, Ca2+, Mg2+). The lysimeters are irrigated related to an average annual precipitation rate of 600 mm/a leading to a liquid to solid ratio (L/S) of about 0.7 per year of operation. Lysimeter tests are more adequate to simulate field scenarios and long-term leaching behavior in contrast to laboratory column tests particularly due to the unsaturated conditions and realistic contact time with the leachant.
In comparison to the leaching of bottom ash (aged for 3 month and non-treated) in column tests the chloride and sulfate leaching in the lysimeters was reduced as a consequence of the previous wet processing. The sulfate release kept almost constant limited by CaSO4 solubility up to an L/S of about 0.7 l/kg. The chloride concentrations dropped quickly, starting from 7300 mg/l, and are now at an almost constant level of 50 mg/l which is significantly above the chloride concentration in the leachant. After an initial decrease of the pH from about 10.4 to 8 at L/S of 0.2 l/kg, the pH increased again and leveled out around 9.8 up to L/S 2.2 l/kg. At an L/S of about 2.5 l/kg now, Cr, Cu are still released. The Cu and Cr concentrations in the leachates were about 760 µg/l and 90 µg/l respectively at the beginning. For both metals the concentration decreased to about 35 µg/l now. The Mo concentrations dropped steadily from 1300 to 250 µg/l, whereas V and Sb concentrations increased in the course of the tests. Fe and Mn are not detectable anymore. More results of this experimental study will be presented and discussed with a special focus on elements forming oxyanions.
Wood treated with nano metal fluorides is found to resist fungal decay. Sol−gel synthesis was used to synthesize MgF2 and CaF2 nanoparticles. Electron microscopy images confirmed the localization of MgF2 and CaF2 nanoparticles in wood. Efficacy of nano metal fluoride-treated wood was tested against brown-rot fungi Coniophora puteana and Rhodonia placenta. Untreated wood specimens had higher
mass losses (∼30%) compared to treated specimens, which had average mass loss of 2% against C. puteana and 14% against R. placenta, respectively. Nano metal fluorides provide a viable alternative to current wood preservatives.