Schemes for source separation of municipal bio-waste aim for maximum coverage and minimum contamination to enable high-quality recovery routes. To identify suitable approaches to improve the separate collection and quality of bio-waste in multi-storey residential buildings, which often exhibit poor source separation, this study evaluates the effectiveness of a set of measures aiming to sensitize residents and facilitate source separation at household level. Three buildings (181 residents) were selected in Kassel (Germany) using a purposive sampling approach. The measures implemented comprised verbal, written and visual communication as well as pre-sorting equipment. By conducting 8 waste characterization campaigns and 2 series of structured interviews (24 and 16 participants, respectively), the qualities and quantities of collected bio-waste were contrasted with the residents' self-perceived level of information and participation in the source separation of bio-waste. Starting at 55%, 46% and 42%, separate collection rates for bio-waste increased to averages of 64%, 60% and 48%, respectively, after implementation of the measures. Impurity contents of separately collected bio-wastes were barely affected, averaging 2%, 8% and 4%, while peaking at 4%, 16% and 8%, respectively. Considering interview response patterns, the withdrawal of access to bio-waste bins from residents not interested in complying with source-separation guidelines seems necessary to achieve low contaminant levels. The residents' perception of individual measures varied across the buildings, indicating a need for site-specific interventions to motivate people to participate in source separation. Further observations suggest that an intensified and sustained feeling of social responsibility and monitoring positively affects bio-waste separation behaviour.

Satisfying the growing demand for plastics while pursuing climate neutrality requires a surge in recycling. Despite being Germany's second-largest plastics use sector, the circularity potential of plastics in buildings and infrastructure (B&I) remains largely unexplored. This study investigates plastic flows, stocks, and legacy contamination for major product groups in Germany's B&I sector from 1950 to 2100, using high-resolution dynamic material flow modeling (six products, eight polymers, seven legacy substances). Results show that plastic stocks are anticipated to increase from 62.9 million metric tons (Mt) in 2023 to 89.5-163.1 Mt in 2100, depending on future consumption scenarios. End-of-life flows were 66 % lower than consumption in 2023 but are projected to at least double by 2100. Achieving high recycling rates is constrained by contaminant thresholds, as demonstrated for DEHP, Pb, HBCD, and (H)CFCs in various products. Consequently, contaminant detection and removal in recycling are crucial for safe and circular plastic use.

Bio-waste treatment can cause substantial environmental impacts, but it also contributes to resource conservation through recovery of fertilizers, biogas, or other bio-based products. In this study, environmentally preferable management schemes for urban bio-wastes from different settlement structures and collection schemes are identified for the city of Kassel (Germany) as a case study. Life cycle assessment is used to assess management scenarios, taking flow-specific waste compositions and established bio-waste treatment processes (open and closed composting, tunnel and plug-flow digestion, municipal solid waste incineration (MSWI)) into consideration. Separate curbside collection rates for bio-waste ranged from 24% to 72%, depending on the settlement structure. Assuming average emissions of German treatment plants, biological treatment pathways are associated with higher impacts than MSWI for several impact categories such as climate change as well as terrestrial and marine eutrophication. Therefore, increased separate collection goes hand in hand with higher environmental impacts in these categories because of higher process emissions (e.g. CH4, N2O and NH3) and impacts from compost utilization. On the other hand, substituting compost for mineral fertilizer results in substantial environmental savings with regard to freshwater ecotoxicity. Consequently, the contents of carbon, nitrogen and potassium were, among others, identified as sensitive parameters affecting environmental performance when composting bio-waste and digestate. The environmental performance of biological treatment pathways for urban bio-waste can be improved by decreasing process-related emissions through optimal operation of treatment plants and by utilizing compost as a substitute for mineral fertilizers.

Large quantities of persistent organic pollutants (POPs) and other persistent, bioaccumulative and toxic substances (PBTs) like heavy metals have accumulated mainly over the last century in reservoirs, such as landfills, dump sites, contaminated sites, and mine tailings, as well as in environmental sinks like soils and sediments. Large floods in the past 20 years have demonstrated the mobilisation of POPs/PBTs from these reservoirs, underscoring the limitations of conventional technical safeguard measures like leachate and wastewater treatment or containment systems at landfills. This study emphasises the need to develop inventories of POPs/PBTs in these reservoirs for the assessment of future risk of increased flooding triggered by climate change and for priority setting of remediation and securing measures. Further, sea-level rise should be included in these assessments as long-term risk for large areas that are likely to be permanently flooded in the coming decades and centuries. In addition, the risk of release of POPs and other PBTs by industries affected by Natural Hazards Triggering Technological Accidents (Natech) should be globally evaluated. The review emphasises the importance of conducting systematic assessments and inventories to understand the risk of these reservoirs for environmental pollution and human exposure. The releases and remobilisation of POPs/PBTs can lead to higher levels in food and drinking water with increased human exposure. In addition to fish, it is crucial to consider livestock grazing in flood plains and other areas affected by floods, and to include them in inventories and risk management. Based on these assessments, appropriate measures must be developed to eliminate or secure the respective reservoirs, following the precautionary approach. Whilst management measures have been initiated in affected areas (including affected feed/biomass), such as floodplains, there is a need to develop them more systematically. This review advocates for a comprehensive and precautionary approach to address the environmental challenges posed by climate change for POPs and other PBTs reservoirs, with an emphasis on increased flooding and sea-level rise. The substitution of POPs/PBTs in non-essential uses should be implemented to reduce future risks. A synergistic implementation of the Stockholm, Minimata, and Climate Convention can be used as frame for inventories and mitigation.

Climate neutrality goals require adapting the management of fossil carbon in waste management. This study evaluates the effectiveness of two key carbon management strategies addressing greenhouse gas (GHG) emissions from residual waste treatment, namely: pre-sorting residual waste in a material recovery facility to remove recyclable, carbon-rich materials (S_MRF) versus post-treatment of municipal solid waste incineration (MSWI) flue gas through carbon capture and storage (S_MSWI_CCS). Using residual waste management in Kassel, Germany, as a case study, GHG emissions are assessed for current and prospective scenarios, accounting for changes in waste inputs, material and energy systems, substitution choices, and uncertainties in treatment technology data. It is shown that MSWI in Kassel emits 857 kg of CO2 per t of wet residual waste, with 31 % fossil CO2. Carbon management strategies can reduce direct fossil CO2 emissions by 27 % (S_MRF) or 90 % (S_MSWI_CCS) and increase the net life cycle GHG savings of residual waste management by a factor of 1.6 (S_MRF) or 2.6 (S_MSWI_CCS), respectively. S_MSWI_CCS offers the highest potential to decrease the GHG footprint of residual waste management and is least sensitive to variations in waste composition, energy and material systems, and substitution choices. Discernibly higher net GHG savings of S_MRF compared to S_MSWI_CCS can only be observed if residual waste is rich in recyclables (low separate collection). Overall, this study highlights the utility of refined scenario, uncertainty and discernability analysis in accounting for local conditions and different settings as well as potential future changes to promote environmental decision support on waste management.

Activated carbons (ACs) are widely used in advanced wastewater treatment to remove organic micropollutants (OMPs), including pharmaceuticals, that evade conventional biological processes. Yet, fossil coal-based ACs generate substantial CO2 emissions and conflict with circular-bioeconomy objectives. Here, we address the critical research gap in sustainable sorbent development by evaluating biogenic ACs produced from underutilized grassland biomass. Using a pretreatment to enrich carbon content and reduce minerals, we generated biogenic ACs from wet meadow (WET) and orchard meadow residues and compared them to Norit SAE Super and PULSORB WP 235 in batch adsorption tests. Despite its higher mineral and ash contents and lower specific surface area than conventional ACs, 100 %-activated WET (WET100) combined balanced micro- and mesoporosity-yielding heterogeneous adsorption sites that conform to Freundlich isotherms-and achieved 50 % OMP removal at a dosage of ∼13 mg L-1, on par with Norit SAE Super (∼12 mg L-1). Strong correlations between OMP removal and ultraviolet absorbance at 254 nm (UVA254; R2 > 0.95) validate UVA254 as a rapid monitoring proxy. Greenhouse gas footprint analyses revealed that substituting coal-based AC with WET100 reduces gate-to-grave emissions by approximately 2.4 t CO2e per tonne of sorbent-translating to potential savings of up to 94 % CO2e when deployed at scale for advanced OMP removal. These findings underscore that biogenic ACs can be seamlessly integrated into existing treatment infrastructure, valorize underutilized grassland biomass, align with circular-economy and EU sustainability objectives, and deliver substantial greenhouse-gas savings compared to coal-based adsorbents.

The use of plastics in buildings and infrastructure has been steadily increasing in the past. Due to the longevity of building components, in the upcoming decades a dramatical growth in waste quantities is expected as a delayed response to the increased consumption, posing a major challenge for waste management and recycling. However, comprehensive high-resolution data on plastic flows in the building and infrastructure sector in Germany have so far not been available. This dataset addresses this gap by presenting simulated data on historical (1950-2023) plastic flows and stocks in the German building and infrastructure sector including their contamination with selected legacy substances based on a dynamic material flow analysis. The focus is on major plastic applications in buildings and infrastructure, namely profiles, flooring, pipes, insulation material, cable insulation, and films. Input data for the dynamic material flow model were compiled from various sources, including scientific literature, reports, statistics, databases, and personal communication with industry stakeholders. The linked data repository contains simulated data, input data, and model files, enabling model reproduction, adjustment, or expansion. This dataset forms a basis for quantitatively assessing current and future plastic cycles in buildings and infrastructure and potential challenges for recycling arising through legacy contamination. The dataset can be reused in different contexts as it bridges various disciplines such as environmental science, industrial ecology, material science, construction engineering, and toxicology, providing valuable insights for research in sustainability, waste management, and pollution mitigation.

The presence of ammonium in leachate from municipal solid waste (MSW) landfills poses a long-term pollution hazard to the environment. Controlled (cat)ion exchange using e.g., potassium has shown promise as a potentially suitable method for in situ pretreatment and removal of ammonium from landfills. However, the spatial heterogeneity of MSW renders tracking the effectiveness of controlled ion exchange in situ an operational challenge. Spectral induced polarization (SIP), a noninvasive geophysical technique sensitive to changes in the electrical properties of subsurface matrices and their interactions with contaminants offers a potential monitoring solution. In the present study, the controlled desorption behavior of ammonium and its relationship with the SIP-derived imaginary conductivity was monitored in flow-through columns filled with MSW. Experiments were carried out under different salinities and leachate concentrations. Ion breakthrough curves were simulated with a reactive transport model that accounts for ion activities at highly saline conditions, enabling the quantification of sorbed ion concentrations on the MSW. For the low salinity injection, imaginary conductivity changes correlate strongly with changes in the sorbed concentrations of cations, closely following variations in sorbed ammonium. At high salinities, the ionic strength contribution dominates changes in electrical signals. While a quantitative assessment of sorbed concentrations is less likely at high salinity, the results show promise in capturing the movement of the ion-exchange front even in high ionic strength environments such as landfills. The laboratory experiments herein highlight the potential and limitations of SIP as a solution for monitoring controlled ammonium release and support its eventual upscaling and field application.

As our planet grapples with the severe repercussions of plastic pollution, mechanical recycling has been proposed as a potential remedy. However, increasing mechanical recycling may have unintended negative consequences. For example, recycling of PVC flooring containing hazardous plasticizers that were used in the past may lead to continued exposure. Here we propose measures to increase recycling while circumventing adverse health impacts caused by legacy additives. For this, we conduct a dynamic substance flow analysis for Switzerland and the time period from 1950 to 2100, focusing on three plasticizers: di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DiNP), and di(2-ethylhexyl) terephthalate (DEHT). We quantify the uncertainty of results, check their plausibility against measured concentrations in samples representative for the Swiss market, and compare them with modeled substance flows in Germany. Based on the cross-checked model, future average concentrations of DEHP in PVC flooring on the Swiss market are expected to be above the legal limit of 0.1 wt % for several decades if increased recycling rates are implemented without additional measures. Phasing out the potentially concerning DiNP, too, and preventing phthalates from entering recycling would lower their average market concentrations to values below 0.1 wt % and enable increasing recycling rates without compromising product safety. Analogous measures could help achieve this goal across other European countries and product groups.

Etwa drei Viertel des in Deutschland verarbeiteten Polyvinylchlorids (PVC) wird zu Bauprodukten verarbeitet. Aufgrund langer Produktlebensdauern sind die PVC-Abfallmengen aus diesem Sektor aktuell deutlich geringer als die Verarbeitungsmengen. Langfristig ist jedoch mit einem Anstieg der Abfallmengen zu rechnen. Die langen Produktlebensdauern haben auch zur Folge, dass PVC-Abfälle aus dem Bausektor Stoffe enthalten können, die vor mehreren Jahren oder Jahrzehnten in der PVC-Produktion eingesetzt wurden, inzwischen jedoch als problematisch eingestuft sind. Ziel der vorliegenden Studie ist es, schadstoffbedingte Herausforderungen für PVC-Kreisläufe im Bausektor in Deutschland zu identifizieren und anhand eines dynamischen Materialflussmodells zu quantifizieren. Das Materialflussmodell basiert auf einer Analyse regulatorischer Rahmenbedingungen, Literatur- und Datenrecherchen sowie Abfallcharakterisierungen. Anhand der Analyse regulatorischer Rahmenbedingungen wurden etwa 680 Stoffe identifiziert, die in PVC-Anwendungen im Bausektor eingesetzt wurden und werden. Der Einsatz von 188 dieser Stoffe wird durch die EU-POP-Verordnung, REACH oder CLP-Verordnung reguliert. Eine Abfallanalyse ergibt, dass PVC-Altprodukte aus dem Bausektor relevante Konzentrationen an Problemstoffen, wie Blei, Cadmium und DEHP aufweisen. Anhand des dynamischen Materialflussmodells wird für die Anwendungen Profile, Rohre und Bodenbeläge gezeigt, dass derzeit ein Nutzlager von etwa 19,0 Mio. Tonnen PVC besteht. Bis 2050 ist zu erwarten, dass die PVC-Abfälle aus diesen Anwendungen von 246.000 t im Jahr 2022 auf 449.000 t steigen werden. Außerdem zeigt das Materialflussmodell, dass PVC-Abfälle aus dem Bausektor mit hoher Wahrscheinlichkeit auch im Jahr 2050 noch relevante Konzentrationen an Problemstoffen enthalten werden. Um zukünftig eine stoffliche Verwertung dieser Abfälle sowie die Etablierung sauberer Materialkreisläufe zu ermöglichen, sind neue Abfallbehandlungsverfahren notwendig, die auf das Ausschleusen der Schadstoffe abzielen, sodass steigende Recyclingmengenpotenziale ausgeschöpft werden können.

Recycling schemes for long-lived products are challenged by the presence of “legacy substances,” which have been used in production in the past, but are nowadays classified as substances of concern. This study quantitatively evaluates the trade-offs between phasing out legacy substances, increasing circularity levels, and reducing life cycle impacts of polyvinylchloride (PVC) window profiles recycling in Germany based on a comprehensive dynamic material and substance flow analysis coupled with a prospective life cycle assessment. Scenario results indicate that although lead had been phased out in virgin PVC by 2015, lead concentrations in end-of-life PVC window profiles will remain above 0.3

Plastic is a popular packaging material, but also criticized as a symbol for the make-use-dispose economy because of its short lifespan, its dependency on fossil fuels, and its potential contribution to marine litter. To identify current and potential future key factors for the environmental performance of plastic packaging waste (PPW) management in Germany, a life cycle assessment considering five different pathways of PPW (including deposit-refund systems, separately collected lightweight packaging waste, and treatment of non-source-separated residual waste) was performed. The analysis related to the year 2017 and also considered prospective changes in the background system until 2050 by adapting inventories to shared socioeconomic pathways in line with the Paris Agreement. Key factors for the environmental performance were determined by perturbation analysis. Source separation, quality and quantity of recycled plastics, and emissions from the thermal utilization of residues were identified as key factors for the environmental performance of PPW management. While benefits of PPW management are expected to decrease due to prospective system changes, source separation and the separation of plastics from residual waste gain in importance. Potential measures for improving the environmental performance should focus on long-term key factors, especially separating PPW from the residual waste (in households or in waste treatment facilities) as well as increasing the quantities and qualities of recycled plastics. The present study showed that the evaluation of system performance in view of changing boundary conditions is key to identify optimal configurations of future PPW management.

Waste management aims to protect human health and the environment by reducing adverse impacts associated with waste generation and treatment. Nevertheless, waste management system performance is typically not monitored based on environmental impacts but based on indicators such as recycling rates. As part of this study, Environmental Waste Utilization (EWU) is introduced as an indicator to monitor the capability of waste management systems to reduce the adverse impacts of waste generation and management. EWU quantifies the share of the environmental value of waste which is preserved through waste management. It is operationalized via a spreadsheet-based calculation tool, the EWU Dashboard. Case studies on plastic packaging waste, PAHcontaminated road debris, and food waste are presented to demonstrate the application range of EWU and its advantages against material efficiency indicators. It is shown that EWU-based monitoring allows for identifying environmentally preferable waste management strategies and enables sound decision support.

Economic and environmental impact assessments are increasingly being adopted in the design and implementation of emerging systems. However, their emerging nature leads to several assessment challenges that need to be addressed to ensure the validity and usefulness of results in understanding their potential performance and supporting their development. There is the need to (i) account for spatial and temporal variability to allow a broader perspective at an early stage of development; (ii) handle uncertainties to systematically identify the critical factors and their interrelations that drive the results; (iii) integrate environmental and economic results to support sound decision-making based on two sustainability aspects. To address these assessment challenges, this study presents an alternative approach with the following corresponding features: (i) multiple scenario development to conduct an exploratory assessment of the systems under varying conditions and settings, (ii) global sensitivity analysis to identify the main critical factors and their interrelations, and (iii) trade-off and ecoefficiency analysis to integrate the economic and environmental results. The integrated approach is applied to a case study on plasma gasification for solid waste management. The results of the study highlight how the approach allows the identification of the dynamic relations between project settings and surrounding conditions. For example, the choice of gasifying agent largely depends on the background energy system, which dictates the impacts of the process energy requirement and the savings from the substituted energy of the syngas output. Based on these findings, the usefulness and validity of the proposed integrated approach are discussed in terms of how the key assessment challenges are addressed and how it can provide guidance for the development of emerging systems.

Solid waste disposal has led to increasing concerns over resource, health, and environmental problems. These issues have been investigated using the Life Cycle Assessment (LCA) technique which helps identify the roots of varying hazards and allows decision-makers to improve the environmental performance of waste management practices. However, there is a lack of review studies that conducted meta-analysis related to developments in critical methodological steps of LCA on solid waste management. To fill this gap, this review paper examines 15 elements comprising the preference of journals, 13 LCA method-related characteristics, and economic assessment. Insights on the limitations and current practices of LCA applications, along with trends for future research, are provided. 240 studies on the LCA of SWM from 2009 until 2020 were systematically reviewed and classified into two major year-groups (i.e., 2009-2014 and 2015-2020) to investigate the trend changes. Among the studied elements, it is found that energy-related applications are on the increase in LCA studies on solid waste management. Anaerobic digestion facilities nearly double in appearance in the second year-group (2015-2020). There is also a more frequent occurrence of certain characterization methods like ReCiPe and CML. Functional units become more diverse, but are overall mostly defined on a mass basis. A frequently identified issue of many LCAs on solid waste management is the ambiguity of data sources such as out-of-date literature or inconsistent geographical references. By addressing issues of methodological standardization, this review study provides a basis to further increase the reliability of results of future LCA studies on solid waste management.

Single-use and packaging plastic (SUPP) strategies are intended to transform the linear make-use-dispose economy of SUPPs into a more circular, resource-efficient one. The aim of this study was to identify optimal SUPP management concepts from a circular-economy-perspective by assessing the effects of different SUPP strategies on household waste management. Data on the generation and management of SUPP-containing household waste in Germany in 2017 were compiled and a material flow model was established. Regulatory SUPP strategies were translated into scenarios (with effects on waste generation and waste composition) and implemented in the material flow model. The effects on material efficiency, waste generation and lower heating values were evaluated and trade-offs between these target dimensions were identified. In Germany in 2017, 32 kg per person and year of SUPP household waste were generated, of which 28 kg per person and year was packaging waste. From a material efficiency perspective, the combination of banning specific non-packaging SUPPs and optimizing source-separation leads to the maximum increase in final recycling rates of SUPPs in household waste, from 38% to 50%. However, in this scenario the amount of SUPP-containing household waste is hardly reduced as compared to the status quo. The trade-offs observed in different waste management target dimensions highlight the importance of understanding the systemic effects of SUPP strategies on waste management in order to identify optimal solutions from a circular-economy-perspective.

Previous studies showed that resources recovery through landfill mining (LFM) is generally challenging from an economic perspective and that a large share of project costs is related to the external treatment and disposal of bulk process wastes such as combustibles and fines residue. Building on these analyses, this study aims to explore the potential for improving the economy of LFM in Europe by creating value from these bulk process wastes. Specifically, the combustibles are treated through internal incineration with subsequent energy recovery, while fines residue is utilized as construction aggregates. These explored possibilities are investigated considering other varying factors at the site, project, and system levels that cover possible LFM project settings in Europe. A set-based modelling approach is adapted to generate multiple LFM scenarios (531,441) and investigate the underlying critical factors that drive the economy of LFM through global sensitivity analysis. Results show that an additional 16% of LFM scenarios become net profitable, mainly driven by fines residue utilization. Avoided costs for re-landfilling are higher than the revenues from construction aggregates. By contrast, internal incineration is driven by the revenues from recovered energy rather than the avoided gate fee, which is substituted by the costs for building and operating own plants. Overall, the policy conditions remain critical to further improve the economy of LFM in Europe. Recommendations include an inclusive quality standard that relies on pollutant leachability rather than total concentration for higher-value application of fines residue and incentive rather than taxation for producing renewable energy from the combustibles.