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Our theoretical work is organized in two independent parts: Part I belongs to the field of condensed matter theory and deals with the spectral signatures of collective states in one dimensional (1D) metals: Electrons in 1D metals are expected to fractionalize into collective spin and charge degrees of freedom. A recent candidate material for the realization of a 1D metal are mirror-twin boundaries in monolayer MoS2. Scanning tunneling spectroscopy was used to record the local density of states along these 1D line defects. In our purely theoretical work, we calculate the local density of states as predicted by Tomonaga-Luttinger-liquid theory in order to reveal the nature of the 1D states spectroscopically. The comparison of measured and theoretical spectra allows us to identify the observed doubling of the energy levels as signature of emergent spin and charge excitations. Part II belongs to the field of non-equilibrium physics and deals with the macroscopic description of equilibration: Equilibration of closed systems is hampered by the diffusive transport of locally conserved quantities as described by fluctuating hydrodynamics. After a sudden perturbation, the buildup of equilibrium fluctuations occurs only algebraically slowly, giving rise to hydrodynamic long-time tails. However, the standard tool in transport theory, the Boltzmann equation, fails to describe equilibration. Adding a noise term restores the missing correlations, resulting in a stochastic Langevin-Boltzmann equation. In our work, we derive a simplified version: a fluctuating relaxation-time approximation. We also set up a stable integration scheme for this type of equation and demonstrate that the numerical solution is in agreement with the predictions of fluctuating hydrodynamics. As an addition, we discuss slow changes of state. We show that the entropy production vanishes algebraically slowly in the adiabatic limit due to the presence of hydrodynamic slow modes.

Two- or three-dimensional metals are usually well described by weakly interacting, fermionic quasiparticles. This concept breaks down in one dimension due to strong Coulomb interactions. There, low-energy electronic excitations are expected to be bosonic collective modes, which fractionalize into independent spin- and charge-density waves. Experimental research on one-dimensional metals is still hampered by their difficult realization, their limited accessibility to measurements, and by competing or obscuring effects such as Peierls distortions or zero bias anomalies. Here we overcome these difficulties by constructing a well-isolated, one-dimensional metal of finite length present in MoS2 mirror-twin boundaries. Using scanning tunneling spectroscopy we measure the single-particle density of the interacting electron system as a function of energy and position in the 1D box. Comparison to theoretical modeling provides unambiguous evidence that we are observing spin-charge separation in real space.

Dissertation, Rheinisch‐Westfälische Technische Hochschule Aachen, 2019; Aachen : Gießerei-Institut der RWTH Aachen, Ergebnisse aus Forschung und Entwicklung 25, 1 Online-Ressource (VI, 148 Seiten) : Illustrationen, Diagramme (2019). doi:10.18154/RWTH-2019-05056 = Dissertation, Rheinisch‐Westfälische Technische Hochschule Aachen, 2019, 0.1 Introduction and motivation: High-silicon nodular graphite cast iron offers numerous advantages over conventional ferritic-perlitic grades. The solid solution strengthened ferritic matrix offers an increased ratio of elongation and strength and provides a more cost-effective mechanical machinability. However, the tensile strength is limited to a maximum of 600 MPa at 4.3% wt-% silicon. Higher silicon contents cause a strong decrease in elongation at fracture as well as a decrease in tensile strength and yield strength. The risk of exceeding a critical silicon content means a reduced process reliability against variations in silicon content during charging and melt treatment. Another disadvantage is the low impact energy of solid solution solidified grades, which is used as a measure of toughness in many guidelines for the design of castings. The aim of this work is to generate well-founded knowledge on materials, on the basis of which new alloy designs can be proposed and tested with which the property range of high silicon-containing ferritic ductile iron can be specifically extended to higher strengths, the process reliability of existing grades can be increased and the toughness can be increased. 0.2 Experimental: To achieve this objective, the cause of the embrittlement phenomenon caused by silicon, i.e. the cause of the decrease in the mechanical properties at more than 4.3 wt-% silicon, is first examined. Subsequently, the suitability of the alloying elements cobalt, nickel, copper and aluminium used individually and in combination for targeted solid solution strengthening with high silicon contents is investigated systematically. With the knowledge about the effect of further alloying elements, the possibility of substituting parts of silicon, which reduces impact energy, is evaluated by the use of selected solid solution strengthening elements. Depending on the varied parameters, matrix and graphite formation, tensile strength, 0.2 % yield strength and elongation at fracture are analysed, interpreted and discussed as experimental target variables, and in selected test series the segregation profiles and the impact energy. 0.3 Results and discussion: In systematic investigations of the mechanical and microstructural properties of alloys with silicon content varying between 3.95 and 5.63 wt-%, the properties of the graphite phase such as nodule size and nodule count as well as the formation of irregular graphite are not coherent with the embrittlement phenomenon and therefore cannot be identified as the main cause of it. In transmission electron microscopic investigations, the existence of ordered areas in high silicon-containing ductile iron is determined. With 3.95 wt-% silicon, a small proportion of B2-ordered areas is detected. A higher proportion of B2-ordered regions together with a comparatively lower proportion of DO3-ordered regions is observed for the brittle failing alloy with 5.36 wt-% silicon. Derived from findings in the field of high silicon steels, the formation of small DO3-ordered domains within larger B2 domains can be identified as the main cause for the complete embrittlement of high silicon-containing GJS with silicon contents above 4.85 wt-%.The suitability for the targeted solid solution strengthening of high-silicon ductile iron was investigated in the present work in extensive alloying experiments. To this end, the solid solution strengthening effect of selected alloying elements and the technologically feasible alloy contents were quantified. The use of copper at 3.8 wt-% silicon is limited to about 0.25 wt-% due to its pearlite forming effect. Copper contents below do not have a solid solution strengthening effect. The use of cobalt leads to combinations of properties that exceed those of the grades that can be achieved with silicon. However, the optimizations achieved are low in relation to the very high price of cobalt and the high alloy contents required. The addition of aluminium leads to a strong strengthening of the ferrite matrix, but with a considerable reduction in elongation, which is due to the interfering effect of aluminium on graphite formation. The full-ferritic alloy produced with 3.8% wt. silicon and 1.5 % wt. nickel provides a tensile strength of 647.3 ± 4.6 MPa with an elongation at fracture of 14.9 ± 0.98 %. The proposed alloy concept thus offers a better performance spectrum than an EN-GJS-600-10 which has been achieved under identical test conditions over 4.3 wt-% silicon, both in strength and elongation at fracture. If the advantages of a single-phase matrix are to be retained, the use of nickel is reduced to 1.5 wt-% due to the perlite promoting effect. By adding 0.7 wt-% aluminium, the formation of pearlite can be shifted to a nickel content of 2.0 wt-%. The combination of 3.8 wt-% silicon, 2.0 wt-% nickel and 0.7 wt-% aluminium with a tensile strength of 712.0 ± 5.9 MPa and an elongation at fracture of 6.7 ± 1.0 % represents the highest strength all-ferritic alloy configuration. These properties correspond approximately to those that can be achieved with an EN-GJS-700-2 strengthened by pearlite, whereby the yield strength exceeds the requirement of the standard by 150 MPa. The best ratio of strength to elongation at fracture is achieved at 3.8 wt-% silicon, 1.5 wt-% nickel and 0.2 wt-% aluminium with a tensile strength of 652.5 ± 9.3 MPa, a yield strength of 524.0 ± 4.3 MPa and an elongation at fracture of 16.0 ± 0.8 %.The findings on the effect of other alloying elements are used to increase the toughness of high-silicon ductile iron materials. The high silicon content is considered to be the reason for the low impact energy. This can be reduced by using alternative solid solution strengtheners while maintaining constant mechanical properties. This concept is investigated by the use of various alloying elements to replace silicon. Toughness can be increased considerably, especially through the use of nickel. After removal of the pearlite resulting from the lowered ratio of ferritizing to pearlite stabilizing elements by a ferritizing heat treatment, the substitution of 0.67 wt-% silicon by 1.47 wt-% nickel causes a reduction of the transition temperature by 50 °C measured in the impact test.0.4 Conclusion and outlook: The understanding of the cause of embrittlement, which occurs at silicon contents above 4.4 wt-%, forms the basis for alloy optimization with the aim of improving the mechanical properties. Knowledge of the cause of embrittlement, the order of iron and silicon atoms, paves the way for the use of further alloying elements for solid solution solidification. Of the alloying elements examined, cobalt, nickel and aluminium are suitable for increasing the strength of ferrite. From a technical point of view, the use of cobalt and nickel is preferable to the use of aluminium. The elongation at fracture during strengthening with nickel and cobalt decreases less than with silicon, in comparison to the use of aluminium, due to the tendency towards improved graphite formation. The use of nickel is economically advantageous due to its significantly lower price compared to cobalt. Compared to ductile iron solidified exclusively with silicon, alloy concepts with an increased performance density are thus available. The lightweight construction potential of high silicon GJS is thus increased. In addition, alloying with nickel and aluminium can significantly improve process reliability and reduce the associated effort involved in process control measures and scrap rates. An improvement of the material behaviour is to be expected in application-related toughness testing methods. The basis for this is the increase in toughness indicated by the shift in the transition temperature. The possibility of increasing toughness by substituting silicon with alternative solid solution solidifying elements can therefore be used to develop new applications in which, due to the toughness requirements, only low-strength ductile iron materials can be used., Published by Gießerei-Institut der RWTH Aachen, Aachen

In the past a variety of $^{18}$F-labeled aromatic amino acids have been developed, primarily for tumor diagnostics with positron-emission-tomography. Recently tryptophan got high attention, since evidence came up that some tumors exhibit an elevated consumption of it. So far, this amino acid could only be radiofluorinated by unsatisfactory approaches. In the work here, a simpler, 3-step method for a nucleophilic radiosynthesis of L-4-[$^{18}$F]fluorotryptophan was developed. For this a carbonyl activated precursor was radiofluorinated by isotopic exchange, followed by removal of the activating formyl group by reductive decarbonylation and subsequent hydrolysis of the protecting groups under acidic conditions. First, the influence of positions of fluorine and of the formyl group on the isotopic exchange was examined in several fluoro-$\textit{1H}$-indolecarbaldehydes where different protecting groups were attached to the indole nitrogen. Further, a decarbonylation reaction with Rh(PPh$_{3}$)$_{3}$ on those molecules was carried out and optimized. The best results regarding radiochemical yield and chemical stability were obtained with 1-benzyl-4-fluoro-1$\textit{H}$-indole-5-carbaldehyde. Based on these results a concept for the synthesis of precursors for L-6-[$^{18}$F]fluorotryptophan and L-4-[$^{18}$F]fluorotryptophan was developed. Hereby the compounds benzyl (2S,5S)-2-tertbutyl- 5-[(1-benzyl-4-fluoro-5-formyl-1$\textit{H}$–indol–3-yl)methyl]–3–methyl–4–oxoimidazolidine- 1-carboxylate and benzyl (2S,5S)–2–tert–butyl–5-[(1–Boc–4–fluoro–5–formyl-1$\textit{H}$–indol–3 yl) methyl]-3-methyl-4-oxoimidazolidine-1-carboxylate were prepared following 11-step linear synthetic pathways with overall yields of about 8 % and an enantiomeric purity of > 99 %. While the radiosynthesis of L-6-[$^{18}$F]fluorotryptophan was not successful due to the failing hydrolysis of the benzyl group, L-4-[$^{18}$F]fluorotryptophan was prepared by the three step radiosynthesis, consisting of an isotopic exchange, a reductive decarbonylation with Rh(PPh$_{3}$)$_{3}$ and the hydrolysis of the protecting groups with HCl, yielding an enantiomeric purity of > 99 %. After optimization of this procedure L-4-[$^{18}$F]fluorotryptophan was isolated in a radiochemical yield of ca. 13 % and a molar activity of > 70 MBq/mmol within about 115 min. Hence, a new and more efficient nucleophilic radiosynthesis of L-4-[$^{18}$F]fluorotryptophan was developed which is now available for preclinical evaluation.

In the past a variety of 18F-labeled aromatic amino acids have been developed, primarily for tumor diagnostics with positron-emission-tomography. Recently tryptophan got high attention, since evidence came up that some tumors exhibit an elevated consumption of it. So far, this amino acid could only be radiofluorinated by unsatisfactory approaches. In the work here, a simpler, 3-step method for a nucleophilic radiosynthesis of L-4-[18F]fluorotryptophan was developed. For this a carbonyl activated precursor was radiofluorinated by isotopic exchange, followed by removal of the activating formyl group by reductive decarbonylation and subsequent hydrolysis of the protecting groups under acidic conditions. First, the influence of positions of fluorine and of the formyl group on the isotopic exchange was examined in several fluoro-1H-indolecarbaldehydes where different protecting groups were attached to the indole nitrogen. Further, a decarbonylation reaction with Rh(PPh3)3 on those molecules was carried out and optimized. The best results regarding radiochemical yield and chemical stability were obtained with 1-benzyl-4-fluoro-1H-indole-5-carbaldehyde. Based on these results a concept for the synthesis of precursors for L-6-[18F]fluorotryptophan and L-4-[18F]fluorotryptophan was developed. Hereby the compounds benzyl (2S,5S)-2-tert-butyl-5-[(1-benzyl-4-fluoro-5-formyl-1H–indol–3-yl)methyl]–3–methyl–4–oxoimidazolidine-1-carboxylate and benzyl (2S,5S)–2–tert–butyl–5-[(1–Boc–4–fluoro–5–formyl-1H–indol–3 yl) methyl]-3-methyl-4-oxoimidazolidine-1-carboxylate were prepared following 11-step linear synthetic pathways with overall yields of about 8 % and an enantiomeric purity of > 99 %. While the radiosynthesis of L-6-[18F]fluorotryptophan was not successful due to the failing hydrolysis of the benzyl group, L-4-[18F]fluorotryptophan was prepared by the three step radiosynthesis, consisting of an isotopic exchange, a reductive decarbonylation with Rh(PPh3)3 and the hydrolysis of the protecting groups with HCl, yielding an enantiomeric purity of > 99 %. After optimization of this procedure L-4-[18F]fluorotryptophan was isolated in a radiochemical yield of ca. 13 % and a molar activity of > 70 MBq/mmol within about 115 min. Hence, a new and more efficient nucleophilic radiosynthesis of L-4-[18F]fluoro-tryptophan was developed which is now available for preclinical evaluation.

Denna rapport är en svensk sammanfattning av licentiatavhandlingen med titeln "Simple Question, Complex Answer. Pathways towards a 50% Decrease in Building Energy Use", som publicerades vid Uppsala Universitet i februari 2014. I denna rapport har jag samman-ställt det som jag anser vara de viktigaste resultaten ur ett länsperspektiv och rapporten riktar sig därför i första hand mot aktörer inom byggnadssektorn i Dalarna. Mer omfattande bild-material, diagram, tabeller och hänvisningar till källmaterial återfinns för den intresserade i licentiatavhandlingen. Min förhoppning är att denna sammanfattning kan ligga till grund för diskussioner och beslut om framtiden för Dalarnas småhusbestånd.

Addressing building energy use is a pressing issue for building sector decision makers across Europe. In Sweden, some regions have adopted a target of reducing energy use in buildings by 50% until 2050. However, building codes currently do not support as ambitious objectives as these, and novel approaches to addressing energy use in buildings from a regional perspective are called for. The purpose of this licentiate thesis was to provide a deeper understanding of most relevant issues with regard to energy use in buildings from a broad perspective and to suggest pathways towards reaching the long-term savings objective. Current trends in building sector structure and energy use point to detached houses constructed before 1981 playing a key role in the energy transition, especially in the rural areas of Sweden. In the Swedish county of Dalarna, which was used as a study area in this thesis, these houses account for almost 70% of the residential heating demand. Building energy simulations of eight sample houses from county show that there is considerable techno-economic potential for energy savings in these houses, but not quite enough to reach the 50% savings objective. Two case studies from rural Sweden show that savings well beyond 50% are achievable, both when access to capital and use of high technology are granted and when they are not. However, on a broader scale both direct and indirect rebound effects will have to be expected, which calls for more refined approaches to energy savings. Furthermore, research has shown that the techno-economic potential is in fact never realised, not even in the most well-designed intervention programmes, due to the inherent complexity of human behaviour with respect to energy use. This is not taken account of in neither current nor previous Swedish energy use legislation. Therefore an approach that considers the technical prerequisites, economic aspects and the perspective of the many home owners, based on Community-Based Social Marketing methodology, is suggested as a way forward towards reaching the energy savings target.

Vägar till en halverad energianvändning i Dalarnas byggnadsbestånd

Dalarnas byggnadsbestånd kännetecknas av en stor andel bostäder, i synnerhet småhus. Permanentbebodda småhus och fritidshus utgör 60% av den uppvärmda arean i länet och bostäderna uppskattas stå för över 80% av energianvändningen i länets bebyggelse. En stor andel av bebyggelsen är byggt före 1961 och nybyggnationstakten har varit mycket låg sedan mitten av 1990 ‐talet. Detta i kombination med en låg rivningstakt gör att energiomställningen måste ske i den befintliga bebyggelsen, förutsatt att rådande trender inte bryts radikalt. Ägarstrukturen av den befintliga bebyggelsen är mycket fragmenterad på grund av den höga andelen småhus, vilket måste påverka strategin för omställningsarbetet. Tänkbara kommande analyser av bl.a. specialenheterna (skolor, allmänna byggnader, idrottsanläggningar etc.), fritidshusen och socioekonomiska faktorer relaterade till länets bebyggelse skulle kunna förfina problembilden och underbygga det långsiktiga strategiska arbetet för energieffektiviseringen i länet.

En enkel Delphi-enkät skickades till drygt 100 beslutsfattare och experter inom Dalarnas byggsektor. Enkätdeltagarna tog ställning till 15 framtidsteser om bebyggelsens energiomställning. Enkätutfallet visar att få deltagare tror att energieffektiviseringsmålen kommer att kunna nås i tid. Staten och fastighetsägarna anses vara de viktigaste aktörerna för att förverkliga framtidsteserna. Lite förtroende finns det för frivilliga beteendeförändringar hos brukarna och stor oenighet råder kring renoveringens betydelse för energiomställningen.

Une décision récente du Tribunal fédéral estime qu'il incombe aux autorités d'exécution des peines d'ordonner une alimentation forcée envers un détenu gréviste de la faim. les regards se tournent vers le soignant en milieu pénitentiaire qui est au risque de se voir sommer d'être l'exécutant d'une telle décision. celle-ci est contraire aux valeurs fondamentales de l'éthique médicale. le respect de l'autonomie d'un patient capable de discernement et qui choisit de protester contre sa situation par ce moyen doit rester au centre de la préoccupation du soignant. Pour préserver cette valeur éthique, l'indépendance du soignant, le respect de la déontologie, la garantie de la confidentialité et le droit à l'objection de conscience sont autant de données indispensables à l'exercice médical en prison autant que dans tout autre lieu de soins.

Modern, small-scale wastewater treatment faces a twofold challenge: On the one hand requirements from legal authorities regarding removal of eutrophying substances have become more demanding. On the other hand high-quality phosphorus reserves are dwindling, which has raised calls for increased recycling. The problem is acute in the county of Stockholm where about 34 000 households are identified to not possess adequate wastewater treatment facilities. In this master’s thesis, four treatment systems, of which three had some phosphorus recycling potential, were compared using life cycle assessment methodology. The small-scale treatment systems analyzed were infiltration, filter beds with Filtralite® P and Filtra P respectively as filter material and a chemical precipitation system. The system boundaries included the extraction of raw materials, production of materials and components, the construction and operation of the systems as well as deconstruction and recycling of the treatment plants. Apart from impacts on human health and acidification potential, which both proved to be of less relevance to the final results, energy usage, consumption of abiotic resources, global warming potential and eutrophication potential were taken into account in this study. The infiltration system attained the most favourable results in all impact categories save eutrophication potential, which was due to both the low usage of energy and resources as well as the system’s high life expectancy. The filter bed system using Filtralite® P demonstrated the best performance in reduction of eutrophying substances. However, the system’s energy demand and emissions of greenhouse gases by far exceeded the other systems’ results in these categories. Both the filter bed system using Filtra P and the chemical precipitation system fared relatively equal in the overall analysis, with moderate impacts in all categories. The nutrient recycling potential was shown to be limited by the waste products’ relatively high heavy metal content. Sludge from chemical precipitation had higher potential for replacement of fertilizer than filter bed material. The chemical precipitation system fared best in the overall assessment. Its technical immaturity and limited data foundation put the alternative using Filtra P into second place. The infiltration system’s limited treatment performance and inexistent recycling potential put this alternative into third place. The alternative using Filtralite® P was ruled out entirely because of its high impact on fossil fuel consumption and global warming. Based on this ranking recommendations were made. Even though the filter bed materials in this study showed excellent phosphorus removal capacity, further research into alternative filter bed materials will have to be made due to the materials’ environmental impacts in other areas. Focus should be on waste material and natural products (such as shell sand) with low environmental impacts from production. Ways of separating heavy metals from plant nutrients need to be explored if nutrient recycling is to be an aim. This study showed that good phosphorus removal characteristics can lead to an increase in other environmental impacts, which in some cases even may outweigh the positive effects of decreased eutrophication. Modern, småskalig avloppsreningsteknik står inför två utmaningar. Å ena sidan har kraven från lagstiftaren på rening av eutrofierande ämnen ökat. Problemet är akut i Stockholms län där det finns ca. 34 000 hushåll som inte anses uppfylla reningskraven. Å andra sidan minskar fosforförekomsterna av hög kvalitet i allt större takt, vilket har väckt krav på ökad återföring av växtnäring. I detta examensarbete undersöktes fyra olika reningstekniker, varav tre har en viss återföringspotential, med hjälp av metodik från livscykelanalys. Systemen som undersöktes var infiltration, filterbäddar dels med Filtralite® P och dels med Filtra P som filtermaterial, samt ett kemikaliefällningssystem. Systemgränserna omfattade extraktion av råmaterial, produktion av anläggningsmaterial och –komponenter, uppförande och drift av systemen samt avveckling av anläggningarna och återföring av restmaterial. Förutom påverkan på mänsklig hälsa och försurningspotential, som visade sig vara mindre relevanta för slutresultaten, omfattade analysen även en undersökning av energianvändning, förbrukning av abiotiska resurser, potential för global uppvärmning och eutrofieringspotential. Infiltrationslösningen fick de mest fördelaktiga resultatvärden i alla kategorierna förutom eutrofieringspotential, vilket kan förklaras med systemets låga energi- och resursbehov samt dess höga livslängd. Filterbädden med Filtralite® P som filtermaterial uppvisade den största förmågan att reducera eutrofierande substanser. Systemets energibehov och utsläpp av växthusgaser översteg dock de andra systemens resultat i dessa kategorier kraftigt. Både anläggningen med Filtra P och kemikaliefällningslösningen fick liknande resultat, med måttlig påverkan i alla kategorier. Systemens återföringspotential visade sig vara begränsad av restprodukternas höga tungmetallhalt. Kemikaliefällt slam hade högre återföringspotential än filterbäddsmaterial. Kemikaliefällning klarade sig totalt sett bäst i studien. Den relativt obeprövade tekniska utformning och det osäkra dataunderlaget ledde till att Filtra P hamnade i rangordningen efter kemikaliefällning. Infiltrationssystemets begränsade reningsförmåga och den obefintliga återföringspotentialen ledde till att alternativet hamnade näst sist. Filtralite® P-alternativet blev placerat sist i rangordningen på grund av dess stora påverkan på förbrukning av fossila bränslen och global uppvärmning. Baserat på rangordningen utfärdades rekommendationer. Trots att filtermaterialen som undersöktes i denna studie har en utmärkt fosforreningsförmåga, kommer det att krävas fler studier med avseende på alternativa filtermaterial, eftersom materialens användning av icke-förnybara energikällor är mycket stor vid tillverkningen. Fokus borde ligga på återvunna eller naturliga material (som t.ex. snäcksand) med låg miljöpåverkan vid tillverkning. Om återföring av växtnäring ska bli ett mål inom småskalig avloppsvattenrening, måste effektiva sätt att separera tungmetaller från växtnäringsämnen utforskas. Denna studie visade att goda fosforavskiljningsegenskaper kan medföra att andra typer av miljöpåverkan ökar, vilket i vissa fall kan leda till att de negativa konsekvenserna överväger nyttan av minskad eutrofiering. Moderne, dezentrale Abwassertechnik steht zwei großen Herausforderungen gegenüber. Zum einen sind die Ansprüche von Seiten des Gesetzgebers gestiegen, die effektivere Abwasserreinigungstechniken erfordern. Zum andern werden Phosphorvorkommen von hoher Qualität zunehmend knapper, was Rufe nach verstärkter Rückführung von Phosphor hat laut werden lassen. Im Verwaltungsbezirk Stockholm, in dem es ungefähr 34 000 Haushalte mit unzureichender Abwasserreinigung gibt, ist das Problem von besonderer Bedeutung. In dieser Diplomarbeit wurden vier Abwasserreinigungssysteme, wovon drei ein gewisses Potential für Phosphorrückführung haben, mit Hilfe einer Ökobilanzierung untersucht. Folgende Systeme wurden untersucht: Eine Infiltrationsanlage, zwei Filterbettsanlagen, eine mit Filtralite® P und eine mit Filtra P als Filtermaterial sowie ein System mit Chemikaliefällung. Die Systemgrenzen umfassten die Gewinnung und Verarbeitung von Rohstoffen, das Errichten der jeweiligen Anlage, deren Betrieb sowie Rückgewinnung und Entsorgung von Restmaterialien. Neben Auswirkungen auf die menschliche Gesundheit und Versauerungspotential, die sich im Nachhinein als weniger relevant erwiesen, wurden Energiebedarf, Verbrauch abiotischer Resourcen, Potential für globale Erwärmung und Eutrophierungspotential untersucht. Die niedrigsten Resultate in allen Kategorien außer Eutrophierungspotential wurden vom Infiltrationssystem erreicht. Filtralite® P erwies sich als am leistungsstärksten, was die Reduktion von eutrophierenden Substanzen angeht. Der Energiebedarf und die Emissionen von Treibhausgasen dieser Alternative überstieg die Ergebnisse der anderen Alternativen in diesen Kategorien doch bei weitem. Filtra P und Chemikaliefällung erzielten moderate Auswirkungen in allen Kategorien. Das Potential für die Rückführung von Pflanzennährstoffen wird, wie die Ergebnisse zeigen, vom relativ hohen Schwermetallhalt in den Restprodukten begrenzt. Chemikaliefällung ist in dieser Studie die beste Alternative. Filtra P zeigte sich als technisch noch zu wenig ausgereift und die Datenunterlage als zu unvollständig, weswegen diese Alternative an zweiter Stelle steht. Die begrenzte Reinigungsfähigkeit des Infiltrationssystemes und das nicht vorhandene Potential für Rückführung von Phosphor führten dazu, dass diese Lösung an dritter Stelle steht. Das System mit Filtralite® P als Filtermaterial wurde wegen seines großen Verbrauchs von fossilen Brennstoffen für wenig brauchbar befunden und steht damit an letzter Stelle. Trotz ihrer hervorragenden phosphorreduzierenden Eigenschaften, wird weitere Forschung im Bereich alternativer Filtermaterialien notwendig werden. Hierbei sollten natürliche Materialien (wie Muschelsand) oder Restprodukte im Mittelpunkt des Interesses stehen, um die Umweltauswirkungen gering zu halten. Wenn die Rückführung von Phosphor ein Ziel der Abwasserreinigung sein soll, müssen Lösungen, Schwermetalle von Pflanzennährstoffen zu trennen, gefunden werden. Diese Studie hat gezeigt, dass gute phosphorreduzierende Eigenschaften zu verstärkten Umweltauswirkungen in anderen Bereichen führen können, welche in manchen Fällen sogar die Vorteile einer verringerten Eutrophierung übersteigen können.