About 60% of plastic packaging in Sweden ends up in mixed municipal solid waste (MSW), which is incinerated with energy recovery. This status quo presents a missed opportunity to meet ambitious recycling targets. This study aims to provide a detailed characterization of plastic packaging in mixed MSW to assess its potential for recycling and its significance in improving the overall recycling rate. A case study involving a Swedish city was conducted wherein a sample of 5500 kg of mixed MSW from 920 households was characterized. From the 31% recycling rate, improvement of up to 59% can be achieved by diverting this misplaced plastic packaging into the existing recycling system. An additional 9% increase remains challenging to achieve due to the occurrence of non-recyclable attributes like black and multilayer packaging. The highlighted key enabler is the combination of correct household waste separation behavior and the establishment of mechanical sorting facilities to recover plastic waste from mixed MSW. These recycling potentials and associated challenges are discussed in the context of Sweden's ongoing efforts across the plastic packaging value chain. Furthermore, the importance of extended waste characterization is emphasized as a tool for identifying recycling potentials and monitoring the effectiveness of measures in enhancing circularity and resource-efficiency. 

Urban Water Infrastructure systems (UWI) are central to functioning cities. For securing a continuous and efficient supply of the systems services, continuous investment, maintenance, and renewal are needed. Neglecting maintenance and renewal can lead to recurrent breakdown problems as systems age, which makes it more and more difficult to secure efficient long-term supply. Globally, many cities struggle with aging water infrastructure, often due to competing funding priorities. Investment in maintenance and renewal is not prioritized. The problem primarily stems from the challenge of reaping the benefits of investments promptly. The long-term benefits gained from investing in the renewal of water infrastructure may be achievable in the long run, resulting in the oversight of such investments. This leads to a build-up of "renewal debt" for future generations to inherit. Addressing this issue is difficult due to various contributing factors and the complex nature of the systems. The study aims to contribute to an increased understanding of the long-term management challenges UWI, the development of improved maintenance and renewal strategies through the examination of water infrastructure management, and the assessment of the adequacy of the maintenance and renewal in a case study, the city of Linköping, Sweden. Employing a mixed methods approach, this study utilized both qualitative and quantitative methods, including interviews, workshops, and data analysis. The findings of the study provided insights into the current status of the water and sewerage networks in Linköping, highlighting the risks to ensuring reliable and sustainable water supply and discussing strategies for improving maintenance and renewal.

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 eco-efficiency 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.

The city's wire-based infrastructure systems (WBIS) are responsible for the delivery of electricity,telecommunications, sanitation, drainage, and district heating and are a necessity for sustainable modern urban life.Maintaining the functionality of these structures involves high costs and, brings disturbance to the local community and effectson the environment. One key reason for this is that the cables and pipes are placed under streets, making system parts easilyworn and their service lifetime reduced, and all maintenance and renewal rely on recurrent needs for excavation. In Sweden, asignificant part of wire-based infrastructure is already outdated and will need to be replaced in the coming decades. Thereplacement of these systems will entail massive costs as well as important traffic disruption and environmental disturbance.However, this challenge may also open a unique opportunity to introduce new, more sustainable technologies and managementpractices. The transformation of WBIS management for long-term sustainability and meeting maintenance and renewal needsdoes not have a comprehensive approach. However, a systemic approach may inform WBIS management. This approachconsiders both technical and non-technical aspects, as well as time-related factors. Nevertheless, there is limited systemicknowledge of how different factors influence current management practices. The aim of this study is to address this knowledgegap and contribute to the understanding of what factors influence the current practice of WBIS management. A case studyapproach is used to identify current management practices, the underlying factors that influence them, and their implicationsfor sustainability outcomes. The case study is based on both quantitative data on the local system and data from interviews andworkshops with local practitioners and other stakeholders. Linköping was selected as a case since it provided goodaccessibility to the water administration and relevant data for analyzing water infrastructure management strategies. It is asufficiently important city in Sweden to be able to identify challenges, which, to some extent, are common to all Swedish cities.By uncovering current practices and what is influencing Linköping, knowledge gaps and uncertainties related to sustainabilityconsequences were highlighted. The findings show that goals, priorities, and policies controlling management are shorttermed, and decisions on maintenance and renewal are often restricted to finding solutions to the most urgent issues.Sustainability transformation in the infrastructure area will not be possible through individual efforts without coordinatedtechnical, organizational, business, and regulatory changes.

Multi-utility tunnel (MUT) have received increasing attention as an alternative method for installing subsurface infrastructure for the distribution of electricity, telecommunications, water, sewage and district heating. MUTs are described as a potentially more sustainable technology than conventional open-cut excavation (OCE), especially if the entire life cycle of these cable and pipe networks is taken into account. Based on an extensive review of the academic literature, this article aims to identify and critically examine claims made about the pros and cons of using MUT for the placement of subsurface infrastructure. Identified claims are mapped, and their validity and applicability assessed. These claims are then analyzed from a sustainability perspective, based on the three sustainability dimensions and a life cycle perspective. The results show that a variety of advantages and disadvantages of using MUTs for subsurface infrastructure are highlighted by the articles, but several of these are without any empirical support. When some form of empirical support is presented, it usually comes from case-specific analyses of MUTs, and the applicability in other MUT projects is seldom discussed. Economic performance is the sustainability dimension that has received the most attention, while environmental performance has not been analyzed in the reviewed literature, which is a major limitation of the current knowledge. In summary, the knowledge about the sustainability performance of using MUTs for subsurface infrastructure is still limited and incoherent. In order to increase the knowledge, this article points out the importance of new case studies, in which the sustainability consequences of using MUTs for subsurface infrastructure are mapped and evaluated by combining both quantitative and qualitative assessment methods.

The transition towards a circular economy is being increasingly envisaged in Europe. Increased utilisation of secondary construction aggregates poses a great opportunity in this regard given its potential to avoid waste disposal, natural resource extraction, and reduce costs. Nevertheless, the Swedish construction aggregates market is dominantly characterised by primary aggregates utilisation. This study employs a qualitative approach to analyse the Swedish construction aggregates market from the user perspective in order to identify the challenges of increased utilisation of secondary aggregates. The dominant and systematic utilisation of primary aggregates is chiefly driven by market processes allowing economic advantages and convenience for the users in doing so, whereas the situational and non-systematic utilisation of secondary aggregates is opportunistically driven by different actors in order to seize opportunities such as avoided costs and improved environmental performance. The realisation of increased secondary aggregates utilisation needs to be first facilitated via changes to the institutional structure that makes such materials a priority issue for the supply chain actors, which necessitates national-level policy interventions and supply chain actor collaborations. Second, the competitiveness of secondary aggregates needs to be lifted to a comparable state to that of primary aggregates, which necessitates the development of specific sectoral application standards and vertical integration of secondary aggregates supply by construction corporations.

The recycling-industry residue called shredder fines (fines) presents a disposal problem,incurs handling costs, and reduces resource efficiency in general. This study aims to identify thechallenges of facilitating fines valorisation in the Swedish context. Hence, the shredding companyperspective of the underlying factors that sustain the current practice of fines management isestablished by studying the case of a specific shredding company using semi-structured interviews.Utilisation in landfill covering offers the company a secure outlet and a legislatively-compliant lowcostdisposal option for fines. Additionally, lack of specific regulatory standards, unfavourableregulation of waste reutilisation, and lack of market demand for secondary raw materials (SRMs)create disincentives to develop valorisation options. Also, the lack of corporate-level focus on theissue has resulted in a lack of organising for and capacities to improve the handling of the material.Initiating fines valorisation needs to challenge these prevailing circumstances and thus necessitatesgovernmental interventions. Simultaneously, favourable conditions for SRM utilisation are needed;that is, established outlets for fines-derived SRMs and clear regulatory and market playing rulesthat reduce uncertainty and investment risk of developing tailored processes for upgrading andresource recovery need to be available.

Millions of tonnes of shredder fines are generated and disposed of globally, despite compelling reasons for its recovery. The absence of a review of previous literature, however, makes it difficult to understand the underlying reasons for this. Thus, this study attempts to investigate and assess what, to what extent, and in what ways shredder fines have been addressed in previous research. In doing so, guidelines are drawn for future research to facilitate the valorisation (upgrading and recovery) of shredder fines. Previous research concerning shredder fines was identified with respect to three main research topics. The material characterisation studies are predominantly confined to the occurrence of metals due to their recovery and contamination potential. The process development studies have often undertaken narrowly conceived objectives of addressing one resource opportunity or contamination problem at a time. Consequently, the full recovery (the retrieval of valuable resources and the bulk-utilisation as substitute material) potential of shredder fines has been largely overlooked. The main limitation of policy and regulation studies is the absence of in-depth knowledge on the implications of governmental waste- and resource-policies (macro-level) on actors’ incentives and capacities (micro-level) for fines valorisation, which is necessary to understand the marketability of fines-derived resources. Undertaking a systems perspective is the key to recognising not only the different aspects within the individual research topics but also the inter-relations between them. It also facilitates the internalisation of the inter-relations into topical research.

The lack of process development based on a comprehensive understanding of the material characteristics and the marketability of recoverables is the primary reason why the valorisation of shredder fines has not been realised in practice. In response, a systematic approach was undertaken consisting of 1) strategic sampling and material characterisation, 2) establishing gate and regulatory requirements of potential valorisation applications, and 3) initial feasibility assessment of the selected applications, to guide future research.

The material was sampled over ten weeks in order to obtain both average values and variations of the physical and chemical composition. Thus weekly, primary fractions and sieved fractions ZA (7.10–5.00 mm), ZB (5.00–3.35 mm), ZC (3.35–2.00 mm), ZD (2.00–0.25 mm), and ZE (0.25–0.063 mm) were prepared, and analysed, and benchmarked against the requirements pertaining to five potential applications. The mercury and aluminium concentrations are the biggest challenge in copper smelting and only ZA and ZB show significant potential. Energy recovery is limited to ZA, ZB, and ZC, provided the chlorine and metals concentrations are decreased. Regarding the recovery as bulk-material in construction, the reduction of the metal content would likely be a pre-requisite.

The utilisation of fines in the individual applications would either leave a significant amount of fines un-valorised or overlook the recovery of valuable resources. The upgrading of the material to suit the different applications would also require addressing multiple material constraints simultaneously. Therefore, realising the full resource potential of shredder fines would require the integration of different upgrading and recovery processes.