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Human activity over the past century has greatly disrupted the natural nitrogen (N) balance, harming health and the environment. Sustainable nitrogen management requires cross-sectoral governance, but studies tracking nitrogen flows across sectors are limited. This study assesses cross-sectoral sources, flows, and sinks of reactive nitrogen (Nr) in Austria, identifying direct Nr inputs and emitting sectors. Using the ‘UNECE-Guidance Document on National Nitrogen Budgets’ and material flow analysis, we quantified Austria’s national nitrogen budget for 2015–2019. Results show the main nitrogen inflows and outflows from imports and exports in the consumer goods and chemical industries. Energy imports also contribute significantly. Some nitrogen is temporarily stored (e.g. in products) or transferred between sectors. However, not all of this N-loss is of direct environmental concern. Annually, 389 kt Nr are lost directly to the environment and causing significant environmental and economic consequences. Direct Nr inputs primarily originate from agriculture (39.3%) and energy/transport (20.7%), with around 30% from cross-border fluxes via water (13.9%) and air (16.6%). The remaining 10% stem from settlements, waste management, and industry. This study highlights the complexity of nitrogen sources and sinks in Austria and underscores the need for improvements towards reduced uncertainties in future research, including higher-resolution spatial data to account for regional variability.

Recent years came with a paradigm shift for wastewater treatment plants (WWTPs) to extend the sole purpose of contaminant removal to an additional function as resource recovery facilities. This shift is accompanied by the development of new European legislation towards better inclusion of resource recovery from wastewater. However, long operational lifespans and a multitude of treatment requirements demand thorough investigations into how resource recovery can be implemented sustainably. To aid the formulation of new legislation for phosphorus (P) recovery specifically, in 2017 we conducted a survey on Austrian WWTP-infrastructure, with a focus on P removal and sludge treatment, as well as disposal and sludge quality of all WWTPs above 2000 population equivalents (PE). Data were prepared for analysis, checked for completeness and cross-checked for plausibility. This study presents the major findings from this database and draws essential conclusions for the future recovery of P from wastewater. We see results from this study as useful to other countries, describing the current state of the art in Austria and potentially aiding in developing wastewater treatment and P recovery strategies.

The Architecture, Engineering, and Construction industries are allocated 40–60% of the worldwide raw material extraction. Construction waste accounts for a significant share of the total waste volume. Therefore, careless handling reduces natural resources and waste deposits (landfills). Furthermore, material reuse and recycling can reduce resource and energy consumption and environmental emissions in some cases. Waste management concepts in the fields of Architecture, Engineering, and Construction are increasingly in the European Union and worldwide focus. A circular economy can be seen as a system in which resource input, waste, emission, and energy leakage are minimised due to closed material loops. Therefore, implementing a consistent Circular Economic requires a holistic approach in which material, emissions, and energy are put into context. This paper aims to analyse dismantling, recovery, and recycling processes and link relevant parameters to assess material sustainability. The technical effort must be made, and the associated costs are compared with the influence of eco-indicators. Furthermore, the data required can be used for the following three areas: Facilitating demolition planning and on-site waste management; resource management at the local/regional/state level; and governmental tax mechanisms.

Statistical entropy analysis (SEA) quantifies the dilution and concentration of conservative substances (e.g., heavy metals) in a system. In this paper, the SEA concept is extended (eSEA) to make it applicable to systems in which the chemical speciation is of particular importance. The eSEA is applied to a simplified region used for crop farming. The extent to which the region concentrates or dilutes nitrogen compounds is expressed as the change in statistical entropy (DH). A detailed derivation for the calculation of DH is provided. The results are discussed for four variations of the crop farming system, showing that the efficiency of crop farming can be expressed by eSEA.

Mineral raw materials have always been of great importance in human history and have been the cause of numerous military conflicts. In addition, new technologies to mitigate climate change, sustainable energy production and mobility, as well as digitalisation, make particular chemical elements indispensable. Some of these raw materials are not mined from own deposits but are minor constituents of basic raw material deposits such as copper, zinc, aluminium and nickel and can only be produced together with them. Since geological resources and reserves of minor metals are generally not included in classification codes — such as JORC — their reserves or resources are not sufficiently documented. Consequently, no reliable assessment of their criticality is possible. We assume that different types of copper deposits have characteristic Se-concentrations. These values are linked and extrapolated with our own database of copper deposits, which is precisely structured according to the type of deposit, tectonic setting, age of mineralisation, copper grades, reserves and resources and geographic location. The result is a tabular listing of selenium’s geological reserves and resources according to the relevant countries, type of deposit, tectonic setting, regions and geological age. These findings show the average Se-content and size of copper deposits. The calculated resources of around 25 million tonnes of selenium are well over two hundred times higher than previously documented and are available to accommodate increasing demand. The methodology presented is suitable for estimating the reserves and resources of other minor metals such as platinum, cobalt, bismuth, molybdenum and tantalum as they are typical constituents of primary mineralisations.

Extended statistical entropy analysis (eSEA) is used to assess the nitrogen (N) removal performance of the wastewater treatment (WWT) simulation software, the Benchmarking Simulation Model No. 2 (BSM No. 2 ). Six simulations with three different types of wastewater are carried out, which vary in the dissolved oxygen concentration (O2,diss.) during the aerobic treatment. N2O emissions generated during denitrification are included in the model. The N-removal performance is expressed as reduction in statistical entropy, ΔH, compared to the hypothetical reference situation of direct discharge of the wastewater into the river. The parameters chemical and biological oxygen demand (COD, BOD) and suspended solids (SS) are analogously expressed in terms of reduction of COD, BOD, and SS, compared to a direct discharge of the wastewater to the river (ΔEQrest). The cleaning performance is expressed as ΔEQnew, the weighted average of ΔH and ΔEQrest. The results show that ΔEQnew is a more comprehensive indicator of the cleaning performance because, in contrast to the traditional effluent quality index (EQ), it considers the characteristics of the wastewater, includes all N-compounds and their distribution in the effluent, the off-gas, and the sludge. Furthermore, it is demonstrated that realistically expectable N2O emissions have only a moderate impact on ΔEQnew.

Multilevel statistical entropy analysis (SEA) is a method that has been recently proposed to evaluate circular economy strategies on the material, component and product levels to identify critical stages of resource and functionality losses. However, the comparison of technological alternatives may be difficult, and equal entropies do not necessarily correspond with equal recyclability. A coupling with energy consumption aspects is strongly recommended but largely lacking. The aim of this paper is to improve the multilevel SEA method to reliably assess the recyclability of plastics. Therefore, the multilevel SEA method is first applied to a conceptual case study of a fictitious bag filled with plastics, and the possibilities and limitations of the method are highlighted. Subsequently, it is proposed to extend the method with the computation of the relative decomposition energies of components and products. Finally, two recyclability metrics are proposed. A plastic waste collection bag filled with plastic bottles is used as a case study to illustrate the potential of the developed extended multilevel SEA method. The proposed extension allows us to estimate the recyclability of plastics. In future work, this method will be refined and other potential extensions will be studied together with applications to real-life plastic products and plastic waste streams.

Building stocks and infrastructures are representing the largest material stock of industrial economies, whereby the largest fraction of building materials is transformed into waste at the end of the life cycle. In order to optimize the recycling potential of buildings, new design-tools and methods are required, whereby it is of utmost importance to have a documentation of the material composition of buildings. In this paper, the methodology for creating a BIM-based Material Passport, enabling optimization of the design of buildings and serving as a documentation of materials existing in buildings, is described. Therefore, a specific building component - the flat roof - of a residential building is used in order to test the proposed tool-chain and show the recycling potential of the built-in materials. Thereby, the recycling potential of a version in timber construction and a version in concrete construction is assessed. The results show that the two versions have a similar recycling rate. However, concrete has a significantly higher mass in comparison to timber, by what the mass of the total waste materials is less in the timber version.

This chapter contains sections titled: The Purpose of Co‐combustion Waste for Co‐combustion Co‐combustion Facilities Principles for Assignment of Wastes to Co‐combustion Facilities Conclusions References