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- Bagheri, Marzieh
(author)
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Sewage Sludge Treatment Scenarios: Techno-Economic Analyses of Energy and Phosphorus Recovery Focusing on Implementation Challenges
- 2024
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Doctoral thesis (other academic/artistic)abstract
- Managing sewage sludge, an inevitable by-product of wastewater treatment processes rich in both contaminants and valuable resources, presents a dual challenge: ensuring pollution prevention by immobilizing or destroying contaminants, and facilitating resource recovery. Balancing these objectives is critical given the growing volumes of sewage sludge and the imperative to both protect the environment and recover valuable resources. The unknown risks of land application of sludge, the currently most common disposal method, make thermal conversion a promising alternative, as it enables energy recovery, the breakdown of potentially harmful organic compounds, and the formation of volume-reduced, sanitized products. Despite the technical feasibility, the commercial development of advanced recovery technologies has been slow. This thesis aims to expand knowledge on different sewage sludge treatment and disposal scenarios under varying conditions; thereby shedding light on implementation challenges, local opportunities, and the financial dynamics critical for phosphorus and energy recovery from the perspectives of wastewater treatment plants, investors, and policymakers. The aim is primarily addressed by performing techno-economic analysis of sewage sludge treatment scenarios, covering the entire sludge treatment process from sludge treatment to end products and disposal (Paper II-V). The techno-economic analysis is supplemented by a review of academic research on sewage sludge management from 1971 to 2019 (Paper I). Results from the analysis of sewage sludge management research (Paper I) show a narrow-focused perspective that often misses the broader, interconnected aspects of sewage sludge management, leading to research that, while detailed, fails to capture the complexity of the field. The investment viability of a new mono-/co-combustion plant for sewage sludge (Paper II) is highly conditional on heat, electricity, and fertilizer prices, and external financial support is often a crucial requirement. Cocombustion of sludge (in low ratios) with K-rich agricultural biomass requirement in and energy demand of a thermal dryer, and by yielding ash that contains phosphorus in a plant-available form. Utilizing existing heat facility (Paper III) and co-combustion to mitigate investment costs and energy demand in sludge management showed the potential to offer a cost-effective alternative to land application. However, the viability of co-combustion hinges on both a high heat market price (Paper II) and the proximity of affordable biomass resources (Paper III). Without these conditions, co-combustion may increase the financial burden of sludge management on wastewater treatment plants and policymakers. Retrofitting a wastewater treatment plant by integrating hydrothermal carbonization in sludge treatment (Paper IV), demonstrated good economic feasibility, primarily due to the avoided disposal costs, while also recovering phosphorus. However, integrating hydrothermal carbonization in a system designed for a thermal dryer may cause a significant reduction in electricity production.Given the high moisture content of sludge and the low market prices for fertilizer, the potential revenue from energy and phosphorus recovery is inadequate to solely drive investment in advanced sewage sludge treatment technologies (Papers II-V). This issue is exacerbated by the fact that most wastewater treatment plants are small in scale. Collaborative sludge management across neighboring wastewater treatment plants (Paper V) increases phosphorus recovery capacity and leverages economies of scale, fostering investment in advanced technology. This strategy presents a significant opportunity to lower the treatment costs and offers a competitive alternative to land application, while encompassing energy and phosphorus recovery into the sludge treatment.In conclusion, resource recovery and pollution prevention in sludge management is a complex task that necessitates simultaneous consideration of technical aspects, product quality, site-specific conditions, and profitability to ensure a comprehensive and viable approach. Leveraging local infrastructure and resources in sewage sludge management is crucial, highlighting the ecessity for strategies to be tailored to the local opportunities and limitations. Such an approach outperforms mono-combustion by eliminating the investment ensures that solutions are not only environmentally sustainable but also economically viable and socially acceptable.
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| 2. |
- Bylund, Jonas R
(author)
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Planning, Projects, Practice : A Human Geography of the Stockholm Local Investment Programme in Hammarby Sjöstad
- 2006
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Doctoral thesis (other academic/artistic)abstract
- Programmes and policies to support ecological sustainable development and the practice of implementation is a question of innovation rather than known and taken for granted procedure. This thesis argues a priori models concerning stability in the social sciences, and human geography especially, are less able to help us understand this practice and planning in such unstable situations. Problematic in common understandings of planning and policy implementation concerning sustainability are the dualisms between physical-social spaces and between rationality-contingency. The first dualism makes it hard to grasp the interaction between humans and nonhumans. The second dualism concerns the problem of how to capture change without resorting to reductionism and explanaining the evolving projects as either technically, economically, or culturally rational. The scope of the thesis is to test resources from actor-network theory as a means of resolving these dualisms. The case is the Stockholm Local Investment Programme and the new district of Hammarby Sjöstad. The programme’s objective was to support the implemention of new technologies and systems, energy efficiency and reduced resource-use as well as eco-cycling measures. The case-study follows how the work with the programme unfolded and how administrators’ efforts to reach satisfactory results was approached. In doing this, the actors had to be far more creative than models of implementation and traditional technology diffusion seem to suggest. The recommendation is to take the instrumentalisation framing the plasticity of a project in planning seriously – as innovativeness is not a special but the general case. Hence, to broaden our tools and understanding of planning a human geography of planning projects is pertinent.
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| 3. |
- Gullström, Martin, et al.
(author)
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Blue Carbon Storage in Tropical Seagrass Meadows Relates to Carbonate Stock Dynamics, Plant–Sediment Processes, and Landscape Context : Insights from the Western Indian Ocean
- 2018
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In: Ecosystems (New York. Print). - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 21:3, s. 551-566
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Journal article (peer-reviewed)abstract
- Globally, seagrass ecosystems are considered major blue carbon sinks and thus indirect contributors to climate change mitigation. Quantitative estimates and multi-scale appraisals of sources that underlie long-term storage of sedimentary carbon are vital for understanding coastal carbon dynamics. Across a tropical–subtropical coastal continuum in the Western Indian Ocean, we estimated organic (Corg) and inorganic (Ccarb) carbon stocks in seagrass sediment. Quantified levels and variability of the two carbon stocks were evaluated with regard to the relative importance of environmental attributes in terms of plant–sediment properties and landscape configuration. The explored seagrass habitats encompassed low to moderate levels of sedimentary Corg (ranging from 0.20 to 1.44% on average depending on species- and site-specific variability) but higher than unvegetated areas (ranging from 0.09 to 0.33% depending on site-specific variability), suggesting that some of the seagrass areas (at tropical Zanzibar in particular) are potentially important as carbon sinks. The amount of sedimentary inorganic carbon as carbonate (Ccarb) clearly corresponded to Corg levels, and as carbonates may represent a carbon source, this could diminish the strength of seagrass sediments as carbon sinks in the region. Partial least squares modelling indicated that variations in sedimentary Corg and Ccarb stocks in seagrass habitats were primarily predicted by sediment density (indicating a negative relationship with the content of carbon stocks) and landscape configuration (indicating a positive effect of seagrass meadow area, relative to the area of other major coastal habitats, on carbon stocks), while seagrass structural complexity also contributed, though to a lesser extent, to model performance. The findings suggest that accurate carbon sink assessments require an understanding of plant–sediment processes as well as better knowledge of how sedimentary carbon dynamics are driven by cross-habitat links and sink–source relationships in a scale-dependent landscape context, which should be a priority for carbon sink conservation.
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| 5. |
- Tilders, Ilke, et al.
(author)
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Nätverk av marina skyddade områden i Sverige : Ramverk och metod för utformning och förvaltning
- 2021
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Reports (other academic/artistic)abstract
- Detta dokument innehåller ett ramverk och en stegvis metod för utformning och förvaltning av nätverk av marina skyddade områden.Ramverket syftar till att stötta utvecklingen av ett mer ekologiskt representativt, sammanhängande och funktionellt nätverk av effektivt förvaltade marina skyddade områden i Sverige. Det möjliggör också en utvärdering av detta nätverk. Ramverket inbegriper principer för hur Havs- och vattenmyndigheten, tillsammans med berörda kustlänsstyrelser, kan arbeta strategiskt med marint skydd ur ett helhetsperspektiv. Med hjälp av ramverket kan tydliga målsättningar slås fast för att uppnå ett ekologiskt representativt, funktionellt och effektivt nätverk av marina skyddade områden. Ramverket åtföljs av en stegvis metod för såväl utformning som förvaltning av marina skyddade områden, och lägger tydligt fram de antaganden som ligger bakom metoden. Ramverket kan även vara ett stort stöd i den framtida ambitionshöjning av målet för marint områdesskydd till 30% – varav 10% strikt skydd – som föreslås till år 2030.Ramverket och metoden konkretiseras i två regionala planer, utarbetade av berörda kustlänsstyrelser. Implementeringen av de regionala planerna kommer att stötta Sverige i arbetet med att uppfylla nationella och internationella åtaganden om ett ekologiskt representativt, sammanhängande och funktionellt nätverk av effektivt förvaltade marina skyddade områden.Ramverket fungerar som ett stöd för dem som arbetar med marint områdesskydd i Sverige på nationell och regional nivå samt länsnivå. Det har i första hand utvecklats för att stötta arbetet vid länsstyrelserna och Havs- och vattenmyndigheten, men även för Naturvårdsverket samt andra institutioner och universitet. Det fungerar även som ett exempel på hur metodiken Conservation Standards (CS) kan tillämpas på nätverk av marina skyddade områden på både nationell, regional och lokal nivå. Ramverket kan fritt anpassas för andra sammanhang.Inom utformning och förvaltning av marint områdesskydd kan ramverket samt dess begrepp, vägledande principer och metod tillämpas på olika nivåer: för ett enskilt skyddat område, i ett län, i ett havsområde, nationellt eller till och med i gränsöverskridande samarbete. I detta dokument beskrivs ramverket främst på regional nivå, i syfte att skapa separata regionala nätverk av marina skyddade områden. Vissa komponenter är dock desamma för alla havsområden i Sverige.Vissa delar av ramverket är fortfarande under arbete. Ramverket kommer att förbättras kontinuerligt under dess implementering.
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| 6. |
- Tilders, Ilke, et al.
(author)
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The Swedish approach to MPA Network Design & Management : Framework and step-by-step guidance
- 2021
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Reports (other academic/artistic)abstract
- This document contains a Framework and step-by-step guidance to support the design and management of Marine Protected Area Networks.The Framework is designed to support the development of a more ecologically representative, better-connected, and more functional network of effectively managed marine protected areas (MPAs) in Sweden. As such, the Framework also enables the evaluation of this Network. The Framework incorporates principles for how the Swedish Agency for Marine and Water Management, together with relevant coastal Country Administrative Boards (CABs), can work strategically with marine protection using an integrated approach. The Framework helps define clear objectives aimed to achieve ecological representativity, functionality, and effectiveness of the MPA Network. It is accompanied by step-by-step guidance for both designing and managing marine protected areas, and transparently lays out the main assumptions behind this guidance. It can also be of great help to Sweden in meeting the potential future ambition of protecting at least 30% of marine waters by 2030, of which 10% should be strictly protected.The Framework and the guidance are applied in two Regional Plans, developed by representatives of the relevant CABs. The implementation of the Regional Plans will help Sweden fulfill its national and international commitments to ecologically representative, well-connected, and functional networks of marine protected areas.The Framework acts as a reference for professionals working with marine protected areas in Sweden on the national level, the regional level, and the county level. It has been primarily developed to support the work of the CABs and the Swedish Agency for Marine and Water Management, but also the Swedish Environmental Protection Agency and other institutes and universities. It also serves as an example of how the Conservation Standards (CS) can be applied to the context of MPA Networks on a national, regional, and local level. Practitioners are encouraged to freely adapt this framework to fit other contexts.The Framework and the step-by-step guidance can be used for the design and management of a single MPA or a set of MPAs, of a regional or national MPA Network, and potentially even of an international network. In this document, the Framework is described primarily on a regional level, with the aim of creating distinct regional MPA Networks. Some components, however, are the same for all regions in Sweden.This document only represents a first attempt at a framework with the definitions, guiding principles, and methodology needed to guide MPA Network Design & Management. It will be refined over time, as it is put into practice and as learning is generated about what works and what does not.
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