Greywater (GW) originates from the kitchen sinks, dishwashers, handbasins, showers, and laundry. GW can account for 70–90% of domestic wastewater volume and contains organics, nutrients, microorganisms, micropollutants, and microplastics. Effective treatment can unlock the potential of GW for non-potable reuse purposes like urban landscaping or irrigation. The overall aim of this thesis was to investigate on-site GW treatment systems which included package-plants, two green walls and a constructed wetland and assess the treatment performance in terms of organic matter, nitrogen (N), phosphorus (P), microorganisms and microplastics (MPs), including the potential resource recovery and safe reuse of GW.

Among the eight package-plants investigated, commercial systems included three type A, two type B and C systems. Type D was a conventional sand filter. After the pre-treatment septic tanks, the treatment unit of type A consisted of a geotextile-fitted trickling filter over a sand bed, type B consisted of a mineral wool filter, and type C had fine plastic mesh filters. The two green wall studies were conducted at a testbed facility, RecoLab, which received GW from a newly developed urban city district (800 P.E.). The treatment efficiency of a pilot-scale indoor green wall with five filter media (pumice, biochar, hemp fiber, spent coffee grounds (SCG), and composted fiber soil (CFS, a paper industry byproduct)) was investigated with vertical flow rates (FRs) of 4.5, 9, and 18 L/d. The real-scale outdoor green wall with four levels filled with biochar and LECA as filter media was investigated for one year, using a subsurface horizontal FR of 430 L/d. A long-term performance evaluation of a constructed wetland for treating GW from a residential building (100 P.E.) in Norway was conducted using GW quality data from 2001–2024. The constructed wetland consisted of a biofilter with Filtralite® media and a horizontal subsurface filter with FiltraliteP® media for enhanced phosphorus removal.

The treatment efficiency of the systems was highly influenced by the filter media and FRs while seasonal temperature changes had a low effect. All the systems demonstrated effective treatment of GW and met the local discharge guideline of 80% BOD reduction and <3mg/L of P in the effluent. However, only the pilot-scale green wall and constructed wetland could produce an effluent with <1 mg P/L, a limit for sensitive regions. Among the filter media, sand, biochar and Filtralite® were the most efficient, up to 4 log10, in removing the microorganisms Escherichia coli, enterococci, Clostridium perfringens, Legionella spp, Pseudomonas aeruginosa and met the European Commission’s guideline for reuse of reclaimed water in agriculture. The quantitative microbial risk assessment (QMRA) on effluent GW from the constructed wetland, for multiple exposure scenario (16 exposures/year) of accidental ingestion of 1 mL, indicated safe reuse in a water cascade during summer season with regards to E. coli and C. perfringens. In addition, using TED-/Pyro-GC/MS, high variability of MPs was observed in GW from different sources of generation while all the filter media of the respective systems effectively retained the MPs, except for mineral wool and hemp fiber. 

The findings of this thesis could contribute to the resource-efficient wastewater management and Water-Food-Energy nexus by demonstrating the potential of decentralized GW treatment systems.

This thesis explores the long-term consequences of hydropower projects by investigating two cases of hydropower, representative for different time periods, and regions throughout the history of hydropower projects within the Swedish context. This investigation informs about the aftermath of different hydropower projects in the face of present-day concerns and the prospects of a green transition and green industrialisation. The Laholm hydropower project is an example of an interwar project in the Swedish South within the county of Halland finished in 1932. The Akkats hydropower project is an example of a post-World War II project within the Swedish Arctic in the county of Norrbotten finished in 1973. By focusing on the storytelling of change that transpired since the conception of the respective hydropower station until the early 2020s, this thesis captures how people recall their relationships to and interaction within the respective context. 

This thesis shows that the Laholm case has become a part of an environment where different actors and local cultural features have become increasingly viewed as a joint landscape. With time, the hydropower station has become relatively well-accepted at the local level, but also criticised at the regional and national levels for its role in the decline of the river ecosystem. The Laholm municipality, tourist industry, and local fisheries have grown dependent on the hydropower company arrangements. By contrast, Akkats was built in a more ethnopolitical context where hydropower is connected to the history of the exploitation of northward regions and the destruction of Sámi culture and land use. The Swedish Arctic is also a region where the state power board Vattenfall became one of the region’s biggest employers. As such, there is often a complex and multifaceted relationship towards hydropower in general. The Akkats hydropower project remains highly contested, but there are also ongoing efforts to emphasise the role that hydropower has had for past employment and present-day character of the region.

Part of the results have also pointed to the unknown variables at the time when the Laholm and Akkats hydropower stations were built that are of great consequence today. Climate change was not a topic of significance when the hydropower stations were built, attitudes have shifted, and the knowledge base about how different species are connected within ecosystems has also grown with time.

This thesis deals with the transition to fossil-free (fuel) passenger transport in rural areas, highlighting the rural inhabitants’ perspective. More specifically, it focuses on how preconditions for rural inhabitants can be met, and what support is needed for rural inhabitants to make the transition from a bottom-up perspective. The environment for transition in rural areas is challenging, with significant accessibility issues. There is a lack of public alternatives, and car dependency is high. There are also challenges in terms of ensuring a transition that is socially sustainable and ensures sustainable accessibility. Alternatives to the fossil-fuel car are essential but, in the context of low populations, it has proven hard to make these alternatives viable. The electric car also stand out as a socio-economic privilege, as only some perceive they can afford it.

The thesis focuses on the two northernmost regions in Sweden, Norrbotten and Västerbotten, where both limiting factors and enablers are identified. Västerbotten and Norrbotten do not represent the ‘ordinary countryside’ but rather an extreme environment, at least from a European perspective. Belonging to Europe’s northernmost region, with the lowest population density, the area presents a very challenging context. Extreme conditions need to be addressed to respond to challenges in these areas, and it is not enough that a transition occurs in more ‘ordinary’ rural areas: change is needed even within the toughest locations.

In general, the transition from using fossil-based fuels to fossil-free fuels is not the only issue involved in the process. For inhabitants in rural areas, the transition involves change in several ways. It encompasses adjusting from mainly personal responsibility and private transport to more sharing and dependency on others. The transition also involves a change in planning strategies, sometimes requiring more planning for travel. This means a change in terms of technology but also behaviour, from one to several modes of transport. It also requires changes in risk planning and how safety measures should be handled. All of these issues need to be addressed to bring about a transition that ensures accessibility for rural inhabitants.

In order to bring about such change successfully, the transition has to be seen from the perspective of already existing accessibility challenges. Key to addressing overall accessibility is making sure there is sufficient accessibility alongside the transition, and search for functional and attractive alternatives. Making the transition possible necessitates a diverse series of solutions, both transport-related but also beyond the mode of transportation, including reduced travel, digital services and enhanced local services. This project has also identified several other key factors that are important considerations in the development and implementation of a diverse set of transport solutions and other accessibility-related measures: enhancing the motivation for fossil-free travel, strengthening collaboration within local and personal communities, working to improve perceived opportunities and adaptability to fossil-free alternatives, supporting and nurturing positive expectations and anticipations regarding the transition, and improving physical proximity to essential services.

Hydraulic turbines are increasingly used for power grid regulation as intermittent energy resources, such as wind and solar power, gain prominence. The power output from these renewable sources fluctuates over short and long periods depending on weather conditions. Therefore, hydraulic turbines often operate away from their design point to mitigate grid imbalances, such as low-load operation, which presents challenges. The guide vanes control the flow, and their opening angle is limited during low-load conditions to restrict the flow rate and reduce power output, creating a high swirl flow condition. During part load (PL) operation, the residual swirl entering the draft tube can initiate a rotating-vortex-rope (RVR) that wraps around a stagnant region, introducing severe pressure pulsations. Some turbines are expected to provide a spinning reserve, enabling rapid responses to grid power shortages. One method to achieve a spinning reserve is to allow the turbine to operate under speed-no-load (SNL) conditions, where the turbine rotates at synchronous speed without generating electrical power. Since the turbine does not extract any power, the energy must be dissipated through the flow field. The resulting chaotic flow field features sometimes rotating vortices attached to the head cover in the vaneless space, extending into the draft tube. The axial flow primarily occurs in a thin region near the outer wall, while a recirculating region exists at the center of the draft tube, potentially extending upstream of the runner. Similar to the RVR, the rotating vortices induce harmful pressure pulsations throughout the turbine, jeopardizing safe operation and shortening the turbine's lifespan due to an increased risk of material fatigue.

This thesis aims to study the flow under low-load operating conditions for a Kaplan model turbine, specifically the Porjus U9 model, using computational fluid dynamics (CFD), and to explore a mitigation strategy that reduces pressure pulsations during these low-load operating conditions. The idea is to limit swirl and, consequently, the pressure pulsations caused by the flow structures by employing asynchronous guide vanes. This involves adjusting some guide vanes to a larger opening angle, while keeping the others closed and maintaining the same power output. Unlike other mitigation techniques, no additional installations are needed aside from an option to control some of the guide vanes asynchronously. CFD is combined with machine learning to explore various guide vane configurations efficiently.

Results indicate that vortices in the vaneless space during SNL operation can be mitigated, significantly reducing the associated pressure pulsations by opening one consecutive section of guide vanes. However, the jet like flow from the opened guide vane section generates a significant radial force on the runner due to the asymmetric flow field and pressure pulsations on the runner blades, oscillating at the runner's rotational frequency. Both issues can be addressed by opening two sections of guide vanes on opposite sides of the runner axis while maintaining most of the mitigation effect. Furthermore, the flow field is predictable, and most stochastic pressure pulsations are reduced, positively impacting the turbine's lifespan. One section with open guide vanes during PL operation can decrease the amplitude of the pressure pulsations related to the RVR rotating mode (RM) and plunging mode (PM) in the draft tube. Conversely, the stochastic pressure variations increase, and the runner is subjected to an asymmetric radial force and pressure pulsations on the blades that oscillate at the runner's rotational frequency, much like for SNL operation. Additionally, efficiency decreases, and the torque on the runnervaries more. The mitigation effect diminishes when opening two guide vane sections, as the RVR reduces in size, but is not completely mitigated.

The asynchronous guide vanes primarily affect the flow upstream of the runner, making the technique suitable for SNL operation, as the vortices originate upstream of the runner. The mitigation strategy is less effective during PL because the RVR originates in the draft tube. While the pressure pulsations related to the RVR can be reduced, significant stochastic variations persist. Furthermore, since the flow rate is higher during PL than SNL, the runner is subjected to higher-amplitude pressure pulsations and a more excessive radial force. Ultimately, implementing asynchronous guide vanes balances increased life expectancy and the cost of turbine operation. Experimental investigations are necessary to validate the above findings and clarify the actual effect on material fatigue and other parts of the turbine not included in the simulations.

Hosting capacity calculations are used to quantify the limitations of electrical networks regarding the installation of new production or consumption. The concept is based on evaluating the performance of the network with increasing amounts of distributed energy resources. Since it involves planning for future conditions of a highly complex system, the calculations are subject to multiple uncertainties, which also extend to the results. Having a clear understanding of how these uncertainties are modelled is critical to a correct interpretation of the results from hosting capacity studies. 

This thesis aims to improve the understanding of different aspects within hosting capacity calculation methods and propose different modelling approaches including low and medium voltage levels, and their interdependence. 

The wide range of options within the hosting capacity calculation methods and the lack of standardisation and defined terminology make it easy to overlook some of the basic principles. This work offers an overview of different hosting capacity calculation methods, accounting for different modelling approaches, the associated uncertainties, and how they affect the interpretation of the results. These insights encourage a reconnection with the fundamental principles that guide the concept of hosting capacity, facilitating a more informed analysis of the results. 

The first part of the work applies a hosting capacity calculation method that considers all possible combinations of locations for PV installations, and based on that, calculates the probability of a limit violation happening. The probability of overvoltage or overloading is used as the performance index and a planning risk is needed to define the limit of acceptable performance. 

The background voltage refers to the voltage magnitude before the installation of any new production or consumption. It accounts for the impact on the voltage of production and consumption in other parts of the distribution network. This thesis introduces a time-dependent model for the background voltage in order to assess the hosting capacity of a LV network, including the impact of already existing PV installations in other LV networks fed by the same MV feeder. 

The background voltage model was extended to analyse the impact of MV reserve operating paths on the hosting capacity of the LV networks. It represents a temporary MV configuration, and the analysis includes the impact of consumption and production throughout the year and along the MV feeder. The analyses results in the impact on the hosting capacity, as well as how long and how many customers it would impact with different reserve operating paths. 

The second part of the work investigates the impact of bigger installations at the MV level. A visualisation method is proposed to assess the trade-off between new installations at MV and LV. This approach enables the evaluation of how installations at one voltage level can constrain the available capacity on the other. The method supports the estimation of a global hosting capacity to be shared among customers across voltage levels. 

In the third part of the work, a model for grid strength for active and reactive power is presented. This model is used to assess the hosting capacity for multiple customers and evaluate the impact of reactive power compensation. 

The findings from this thesis cover multiple aspects of hosting capacity calculations, reveal the interdependency between voltage levels and provide methods to address and visualise the mutual dependency between new installations at LV and MV networks. A critical analysis and comprehensive discussion of different ways the hosting capacity can be modelled and shared between customers is presented, as well as recommendations for future work.

The global construction sector has witnessed exponential growth in concrete utilization over the past seven decades, with annual consumption over 9.42 billion m³ in 2021. This surge, driven by rapid urbanization, has positioned concrete as the dominant construction material while creating critical environmental burden. In response to these challenges, the Swedish concrete industry has committed to making all concrete climate-neutral by 2045, with market-ready climate-neutral concrete available by 2030. To reduce the negative environmental impact of the concrete, transitioning from linear to circular economic models presents a viable approach, particularly through integrating wastes and industrial by-products (e.g., fly ash, slag) as supplementary cementitious materials (SCM) into concrete formulations. However, this eco-friendly construction practice faces severe challenges at establishing and executing SCM concrete configurations (including concrete mixes and site construction methods). During plan establishment, the systemic environmental and economic impacts of SCM concrete—spanning cradle-to-practical-completion phases—remain insufficiently examined. 

The complex interactions between SCM concrete’s mechanical properties (e.g., prolonged hydration and decreased early strength) and site construction methods (e.g., formwork duration, occupancy of labour and equipment) increase the difficulty in quantification. For example, while SCM concrete reduces embodied carbon in production, its delayed strength gain may necessitate prolonged formwork use or require energy-intensive methods (e.g., thermal treatment) to meet project timelines. To mitigate this, engineers might opt for a higher concrete grade to accelerate early strength development—though this risks offsetting sustainability gains of SCM concrete. Such adaptations often erode projected emission reductions and inflate costs, shifting burdens across stages. These cross-stage trade-offs underscore the need for integrated, cradle-to-practical-completion evaluations of the environmental and economic impacts of SCM concrete to avoid suboptimal overall performance.

Furthermore, optimising SCM concrete configurations based on quantified performance metrics presents a significant computational challenge. This is due to the exponentially growing solution space resulting from the numerous combinations of SCM concrete mix designs and site-specific construction methods. As a result, exhaustive exploration of the solution space becomes computationally intensive, often leading to incomplete identification of optimal trade-offs between environmental benefits (e.g., reduced GHG emissions) and economic constraints (e.g., labour costs, construction time). Even after obtaining optimal SCM concrete configurations, real-world variability—such as fluctuating temperatures affecting curing rates —introduces uncertainty into project outcomes during site execution. For example, warmer weather than predicted will make former planed thermal curing measures become over-protection, leading to unnecessary expenses and energy consumption. To address this, robust optimisation frameworks are needed to simultaneously account for cross-stage interdependencies and operational uncertainties. 

Despite the critical need for integrated solutions, existing research on SCM concrete construction has largely remained discipline-specific—a divide rooted in the fragmented nature of the construction industry and its supply chain. Studies on SCM material properties are primarily limited to construction materials research, while on-site optimisation is explored within construction management. This fragmentation has prevented the integration of these two critical dimensions into a unified framework, limiting a comprehensive understanding of their collective impacts on a project’s economic and environmental performance. Based on gaps in previous studies, three research questions are formulated: 

RQ1: What systemic interdependencies exist between SCM concrete’s mechanical properties and site construction methods, and how do these interactions influence the cradle-to-practical-completion performance of SCM concrete?

RQ2: What critical trade-offs arise when optimizing SCM concrete configurations across environmental benefits and economic constraints, and how can these trade-offs be systematically prioritized to avoid sub-optimisation?

RQ3: What influence do weather-induced uncertainties have on the trade-offs between environmental benefits and economic constraints of SCM concrete construction practice across cradle to practical completion, and how should site construction methods be dynamically adapted to optimize these objectives under variable conditions?

To address the formulated research questions, the research underlying this thesis was conducted in three following procedures: (1) Problem identification, which investigated both the operational demands of SCM concrete construction practice and existing theoretical limitations hindering the realization of full eco-friendly potentials of SCM concrete; (2) Method development, which constructed a holistic approach to overcome the identified theoretical gaps; (3) Method validation, which built three according prototypes as practical solutions to the identified problems and applied them to actual construction case projects to examine the effectiveness of the proposed methods. Each research question is addressed by a purpose-built model tailored to the specific technical and decision-making challenges associated with the use of SCM concrete. These models offer targeted solutions across life cycle analysis, optimisation, and uncertainty management:

CSCD (Collection–Simulation–Calculation–Decision) for RQ1: This model integrates Discrete Event Simulation (DES), environmental impact assessment, and concrete maturity analysis to evaluate the environmental and economic performance of SCM concrete across the cradle-to-practical-completion span. It explicitly captures the interdependencies between SCM concrete’s mechanical properties (e.g., strength development) and construction practices (e.g., formwork duration), supporting holistic performance quantification.

ESO (Ensemble learning–Simulation–Optimisation) for RQ2: This model combines ensemble machine learning techniques with simulation-based optimisation to efficiently navigate the expanded solution space of SCM concrete mixes and site construction methods. It enables comprehensive multi-objective trade-off analysis between environmental benefits (e.g., GHG emissions reduction) and economic constraints (e.g., cost, time), while minimising computational demand and the risk of sub-optimal outcomes.

MADS (Modelling–Automation–Decision Support) for RQ3: This model integrates dynamic weather data, concrete maturity modelling, and automated decision rules to support the dynamic adaptation of construction practices—such as curing duration and protection measures—in response to temperature fluctuations. It enhances the reliability and responsiveness of SCM concrete implementation under weather-related uncertainties.

This research directly supports the strategic goals of the Swedish roadmap for climate-neutral concrete through a systematic and holistic approach to the use of SCMs. The roadmap emphasizes several key strategies, including: optimising the composition of concrete, replacing parts of the cement with alternative binders; contributing towards ensuring that the right concrete is used in the right place, i.e. avoiding higher concrete quality than necessary for the bearing capacity and durability of the building. The proposed research approach contributes to each of these areas in the following ways:

(1) Optimizing Concrete Composition. In alignment with the roadmap’s focus on reducing cement content, this research provides a structured method for evaluating and selecting SCMs as partial cement replacements. The CSCD model, developed in response to RQ1, enables a comprehensive environmental and economic assessment of different SCM concrete mixes, considering their mechanical behavior and performance during construction.

(2) Ensuring the Right Concrete is Used in the Right Place. Overdesign of concrete—using unnecessarily high-grade concrete mixes—leads to avoidable emissions and costs. The research supports decision-makers in selecting concrete grades that match structural needs without overdesign. The CSCD model quantifies performance relative to functional demand, minimizing unnecessary environmental burdens and ensuring practical suitability on-site.

(3) Lifecycle-Based Environmental and Economic Assessment. Avoiding impact shifting across project stages requires integrated evaluation from material selection to project delivery. This research embeds a cradle-to-practical-completion perspective throughout all phases of assessment. While the CSCD model forms the backbone of this life cycle analysis (per RQ1), the ESO and MADS models (developed under RQ2 and RQ3) extend this thinking into planning and execution, capturing downstream impacts and variability.

(4) Multi-Objective Optimization for SCM Usage Planning. Identifying optimal SCM configurations under multiple, often conflicting objectives—such as reducing emissions while controlling costs and timelines—is critical. This research introduces the ESO model, developed for RQ2, which combines simulation with ensemble learning to explore a vast solution space efficiently. It reveals optimal trade-offs while managing computational complexity.

(5) Managing Construction Uncertainties and Climate Variability. Real-world variability, especially weather-induced fluctuations, can disrupt curing rates and lead to mismatches between planned and actual outcomes. To address this, the MADS model, developed for RQ3, enables dynamic adaptation of construction measures such as curing protocols. It enhances the reliability and environmental performance of SCM concrete application under uncertain site conditions.

Following the expansion of hydropower in the Swedish north during the 20^th century, wild salmon populations became extinct in most rivers, along with the disappearance of salmon fisheries that had sustained communities for millennia. The most rapid phase of this decline occurred between the 1940s and 1970s. Against this backdrop, this dissertation seeks to examine and explain how societal forces and power relations – both between humans and between humans and salmon – shaped the extinction processes of this period. To historicise these events, the analysis also considers long-term shifts in human-salmon relationships. A central finding of this dissertation is that the extinction of genetically distinct salmon populations can be understood as the culmination of a prolonged historical process within the industrial age, marked by cyclical patterns of capitalist-driven metabolic rifts in salmon reproduction cycles, social marginalisation of locals fishing salmon, and gradual decline of salmon populations. By the 1940s, plans were underway for an accelerating phase of hydropower expansion that would push most wild salmon populations to the brink of extinction. In response, intense debates arose concerning how salmon could be protected. Within this context, fisheries biologists successfully pushed the hydropower industry to finance investments in smolt breeding, aiming to sustain offshore fishery yields despite the obstruction of salmon migration to home rivers. Securing these investments did, at the same time, strengthen the financial resources and professional status of the field of fisheries biology. Ultimately, the expansion of hydropower was propelled by economic and political imperatives rooted in the belief that production and consumption must continuously grow. By theorising that capitalistic extraction has been legitimised by ideas of human superiority over nonhuman beings, this dissertation argues that such ideological frameworks led decision-makers to rationalise population-level extinctions as an unavoidable trade-off for increased industrial extraction and production. This perspective is evident in debates over salmon conservation, where salmon were framed primarily as economic assets and sources of profit, rather than as living beings with intrinsic value. The extinction processes meant that salmon, inherently bound to their home rivers yet prevented from returning, became lost to the world by being lost within it. This loss had, in turn, profound consequences for local environments, as salmon played a crucial role in ecosystem stability. For local communities, the population-level extinctions represented not only the disappearance of a vital sustenance and trade resource but also a deeper cultural loss – an erosion of traditions, identities, and knowledges tied to these fish and their lifecycles. The broader objective of this dissertation is to illuminate the global issue of accelerating biospheric impoverishment caused by human activity and its far-reaching consequences for humans, other life forms, and ecosystems. In this context, contributing with knowledge on fish is particularly relevant, as they are among the most threatened groups of living beings on the planet. The relevance of this project is further underscored by the severe decline of fish populations in Swedish waters and the fact that, despite this crisis, fish have remained a marginal topic in environmental history research on Sweden.

As manufacturing companies confront mounting environmental, social, and economic challenges, digital transformation emerges as a vital enabler of sustainability. However, achieving meaningful impact requires more than adopting advanced technologies—it demands collaborative approaches that embed sustainability into the core of industrial value chain. This thesis explores the twin transition—the integration of digital transformation and sustainability—by investigating how value co-creation and collaboration between manufacturing companies and technology solution providers (TSPs), as well as among TSPs themselves, contribute to sustainable production.

To address this, the thesis develops a conceptual value co-creation framework that highlights how digital technologies can drive sustainability through collaborative efforts among manufacturers, technology solution providers, and other key stakeholders. Based on empirical insights from Papers 1 to 5, the framework is presented as a value constellation, in which manufacturers and TSPs collaborate to adopt tailored digital solutions that derive sustainability. This approach shifts the focus from fragmented or isolated initiatives toward a collaborative value constellation, where digital technologies are applied to improve operational performance and contribute to environmental and social outcomes.

The empirical studies presented in Papers 1 to 5 demonstrate that both manufacturers and TSPs encounter a range of challenges in pursuing sustainability. Papers 1 and 3 identify internal constraints within TSPs, including limited financial and human resources, a predominant emphasis on short-term customer demands, and difficulties in allocating resources toward sustainability-focused research and development. In addition, Papers 3 and 5 highlight several external challenges, such as low market demand for sustainable solutions, fragmented or inconsistent regulatory requirements, and the absence of effective policy incentives. Paper 5 further reveals that cultural resistance and organisational inertia—particularly within manufacturing companies—pose significant obstacles to the adoption of long-term sustainability practices. The findings in Papers 2 and 3 suggest that collaborative networks can play a critical role in addressing these challenges. By facilitating knowledge exchange, distributing investment risks, and promoting alignment of innovation strategies, such networks offer a means to support more coordinated and effective approaches to sustainability across the manufacturing and TSP value chain.

Paper 5 further reveals that while digital technologies are often used in operational improvements, they are much less commonly applied in strategic planning or in tracking and improving sustainability performance over time. This gap points to a need for a more comprehensive approach that applies digital tools across all phases of sustainability implementation—from planning and execution to monitoring and continuous improvement.

This thesis contributes a model that brings together theoretical insights and empirical findings to support the twin transition, with a particular focus on how manufacturers and TSPs can collaborate to drive meaningful, sustainability. 

The thesis framework is built upon three foundational pillars: (1) leveraging strategic use of digital transformation to foster sustainability into both technological and non-technological innovation processes, (2) advocating inter-organizational collaboration through stakeholder engagement fosters aligned digital and sustainability efforts, and (3) embedding value co-creation as a systemic approach across interconnected actors to drive sustainability. By synthesizing theoretical and empirical insights, this research contributes to the fields of innovation management, digital transformation, and sustainability studies. It offers both conceptual clarity and practical guidance for companies seeking to navigate the twin transition.

Zeolites are crystalline aluminosilicates with well-defined 3D porous structures consisting of tetrahedral units of aluminate (AlO45-) and silicate (SiO44-) ions. Zeolites can be classified by pore size, with small-pore zeolites featuring 8-membered rings and pore openings around 3-4.5 Å, medium-pore with 10-membered rings and pore sizes of 4.5-6 Å and large-pore with 12-membered rings and pore sizes between 6-8 Å. Zeolites are widely used in catalysis, adsorption, and separation processes in the form of pellets and membranes.

Small-pore zeolite membranes, such as CHA (0.37 nm pore size) and DDR (0.36 nm pore size), have been extensively evaluated for a variety of separations, due to their suitable pore sizes, which enable size-based separation, along with their excellent thermal stability and chemical resistance. Particularly in gas separation, these membranes have demonstrated exceptional performance for a range of industrially relevant gas pairs, such as CO2/CH4, CO2/N2, N2/CH4, and H2/CH4, highlighting their strong potential for biogas and natural gas upgrading. Nevertheless, further fundamental studies are needed in order to improve the membrane materials, deepen our understanding of the mass transfer mechanisms in zeolites, and optimize their performance in practical applications.

In this thesis, the adsorption isotherms of the common components of natural gas and biogas, CO2, CH4, N2, and He were experimentally measured over wide temperature ranges on all-silica CHA, DDR, and MFI zeolite large crystals. The Toth equation was fitted to the measured adsorption data, and adsorption parameters, such as adsorption capacity at saturation (Csat), affinity constant (b), Toth heterogeneity parameter (t), enthalpy of adsorption (ΔHads) and adsorption entropy (ΔSads) were estimated. The estimated adsorption parameters presented in this work are accurate, primarily due to the large crystals used for the adsorption measurements and the recording of low-temperature adsorption isotherms over broad temperature ranges. These data are invaluable for understanding adsorption and mass transfer in zeolite materials, as well as for advancing the development of zeolite materials for gas separation.

The second part of this thesis evaluates highly permeable DDR disc membranes under various conditions for the separation of CO2/CH4 and H2/CH4, gas pairs that are particularly relevant for natural gas and biogas upgrading. For CO2/CH4 separation, the exceptionally high selectivity of 2325 paired with a high CO2 permeance of 34 × 10-7 mol/(m2·s·Pa) was observed for an equimolar mixture at a feed pressure of 3 bar and a temperature of -30 ℃. The highest CO2 permeance was recorded at the same feed pressure and a temperature of +10 ℃ with a value of 44 × 10-7 mol/(m2·s·Pa), while the selectivity remained remarkably high at 1118. For H2/CH4 separation, a H2 permeance of 7.2×10-7 mol/(m2·s·Pa) was recorded for a feed of a 1/1 H2/CH4 mixture at room temperature and pressure of 3 bar. The high permeance was paired with a H2/CH4 selectivity of 207, markedly higher than previously reported for DDR membranes. Furthermore, a mass transfer model accounting for adsorption, surface barrier and surface diffusion was fitted to the experimental data and showed that the model could accurately describe the mass transfer in the zeolite pores, and that the surface barrier was the limiting mass transfer step. Based on the separation results, one-stage membrane processes for upgrading biogas to biomethane using DDR membranes, at three different operating pressures were designed and showed that in all cases a significantly low membrane area, methane slip, and electricity power was sufficient compared to the polymeric membranes processes.

The final part of this work focuses on upgrading synthetic natural gas mixtures with a composition that is typical after a Joule Thompsson process in the industry using CHA membranes. The membranes exhibited high flux at a feed pressure of 30 bar while the selectivities for the gas pairs of CO2/N2, CO2/CxHy, and N2/CxHy were also excellent. The optimal temperature for CO2 removal was found to be around 25 °C, where a great CO2 flux of 1.2 mol/(m²·s) was observed coupled with a CO2 permeance of 13×10-7 mol/(m²·s·Pa). Under these conditions, high selectivities for CO2/CH4, CO2/C2H6, and CO2/C3H8 of 68, 101, and 190, respectively, were observed. The optimal temperature for N2 removal was around 35 °C; at this temperature high N2 flux of 2.5×10-3 mol/(m²·s) was observed, with the N2 permeance reaching 1×10-7 mol/(m²·s·Pa). Finally, a membrane process, designed based on the separation data, showed that only 10.4 m2 membrane area is sufficient for the upgrading of 1000 Nm3/h natural gas to pipeline gas at a feed pressure of 30 bar, which is approximately 102 times smaller than the membrane area needed in polymeric membrane processes. 

Overall, the findings in the thesis suggest that small-pore zeolite membranes hold great potential for upgrading biogas and natural gas.

Contaminated soil is a global problem due to its association with environmental and health risks. The wood impregnation industry is one example that has left many sites co-contaminated with polycyclic aromatic hydrocarbons (PAH) and metal(loid)s, such as arsenic. 

Despite the negative environmental and economic aspects of landfilling, this is the most common soil remediation technology in Sweden and Europe.

This study sought to investigate the effects of electricity driven remediation on soil contaminated with arsenic and PAH, to contribute to the knowledge about using it as an alternative to landfilling.

The technology can be practiced in situ, since it uses electricity applied over electrodes inserted into the soil. The intentionally corroding iron rod electrodes sought to amend the soil with iron. This was done to allow for formation of iron oxides in the soil, that could immobilise arsenic by chemical adsorption, thereby reducing the risk of spreading of arsenic and lowering of its toxicity.  Simultaneously, the intention was to degrade PAH with hydroxyl radicals, forming from hydrolysis of water molecules in the soil. To test the effects of the technology on arsenic immobilisation and PAH degradation in sand and peat, experiments were set up on laboratory and intermediate scales. An additional experiment was performed in microcosms to test how varying redox conditions affect arsenic immobilisation in treated soil. 

Results showed that the concentrations of arsenic and PAH decreased in both soil and soil solution. However, low redox conditions and high organic matter content were two factors reducing the remediation efficiency. During anoxic conditions, an increase was shown in the exchangeable arsenic fraction. Moreover, the treatment was more efficient in sand than in peat, most likely due to its lower organic matter content. 

This study showed that electricity driven remediation can be suitable for arsenic immobilisation and simultaneous PAH degradation. It could be a potential alternative to landfilling, especially when taking site-specific conditions into account, and when combining it with other remediation techniques. However, more studies are needed to confirm that, and the exchangeable arsenic fraction needs to be reduced prior industrial implementation.