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Avsaltning av havsvatten : En fallstudie över alternativ för vattenförsörjning i kustområden / Seawater Desalination : A case study of coastal water supply optionsNorlin, Ylva, Taxén, Linnea January 2023 (has links)
Rapporten ämnar undersöka hur avsaltning av havsvatten används för att trygga dricksvattenförsörjningen i Värmdö respektive Östhammar kommun. Vidare behandlas även de juridiska aspekterna kring ämnet på såväl kommunal som nationell nivå. Arbetet avser även att utreda vilka risker som finns med att använda avsaltningsanläggningar för såväl konsumenterna av det avsaltade vattnet som för närliggande marina miljöer. För att besvara frågeställningarna genomfördes en fallstudie över de två kommunerna. Undersökningen baseras främst på litteraturstudier som kompletterats med intervjuer och studiebesök. Genom studien har det kunnat fastställas att avsaltning sker i de båda kommunerna, men i vilken omfattning detta sker har inte varit möjligt att besvara, vilket främst beror på att mindre avsaltningsanläggningar inte omfattas av tillståndsplikt. Således finns inget register över antalet anläggningar inom kommunerna, vilket ytterligare försvårade kartläggningen. Överlag finns inget sammanhängande regelverk för avsaltning samt att flera aktörer är inblandade i regleringen, vilket ytterligare kan försvåra kartläggning samt inkorporering av metoden för vattenförsörjning. Gällande påverkan på marina miljöer sågs brinet som den primära riskkällan, medan hälsoriskerna med att konsumera avsaltat vatten är omdiskuterat. Det fanns även få studier ämnade åt de svenska förutsättningar, därav rekommenderas ytterligare studier på området. Slutligen rekommenderas ökad samverkan mellan kommuner samt resurseffektivisering av vattenförsörjningen ifall avsaltning bedöms som olämplig inom kommunerna. / The purpose of this report is to investigate if an expansion of desalination plants in Sweden could secure and amplify fresh water resources. The use of desalinated water in Sweden is currently not that widespread and there are few studies on how such expansion could impact the Swedish environment. The report aims to further investigate various health risks of consuming desalinated water and whether algae toxins from the Baltic Sea could be a potential health threat. To answer these questions a case study was conducted on the Värmdö municipality and Östhammar municipality, two archipelago municipalities located on the East coast of Sweden in Stockholm County respectively Uppsala County. Interviews with employees in both municipalities were conducted and supplemented with more interviews of other people active in the field. One of the main reasons for the interviews with employees in both municipalities was to answer the questions of how fresh water supply could be secured in the future if desalination plants were not a suitable option. Although the report was primarily based on a literature study, it was further complemented by two field excursions where two desalination plants were studied. The result of the study was that it was not possible to execute a detailed mapping of the number of desalination plants and how widespread desalination was in the municipalities, due to the fact the smaller facilities were excluded from permit obligation. A thorough mapping was likewise seen as expensive and time consuming which, if conducted by the municipalities, would require a redistribution of financial resources. The municipalities' attitude to desalination was positive, but it was not currently used in their fresh water supply. However there is currently no cohesive regulatory framework for desalination, and there is likewise a lack of a single authority with primary responsibility for desalination, which could aggravate implementation of desalination in Sweden. Consequently expanded cooperation between nearby municipalities as well as more resource efficient methods were proposed as solutions if desalination was unsuitable. The health risks of consuming desaline water was very oxymoronic; some sources said the lack of minerals in the water could result in cardiovascular diseases and other health issues, whereas other sources argued that they were due to different lifestyles. In addition algae toxins are common in the Baltic Sea which likewise could be a health risk. Overallt more research on the health risk of consuming desaline water is recommended since there are few studies on Swedish prerequisites. The main environmental impacts were the residual product from desalination, namely brine. The conclusion was that brine in low amounts probably did not pose a threat to the marine ecosystems and thus the environment, but again further studies are recommended.
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Current Factors and Preferences Influencing Fish and Seafood Consumers in the Baltic Sea RegionCamillo, Cameron January 2023 (has links)
Eating fish and seafood is integral to the Baltic Sea region's food culture. Overfishing, pollution, and seabed destruction have made the Baltic Sea one of the world's most overexploited and polluted seas. The governments of the nine surrounding countries are collaborating to minimize all forms of impact to ensure the equitable management of this nurturing ecosystem, now vulnerable. However, it will take more than restoration and preservation projects to ensure its health. Indeed, institutions need to understand and integrate into their action plans the factors influencing seafood consumers to steer their choices towards more sustainable, environmentally-friendly fishing and recreate a link between the consumer and his or her plate. Based on a holistic approach, the study aimed to determine preferences and factors influencing consumer behavior. The study was carried out via an online survey in the winter of 2023. The following aspects were collected: socio-demographic characteristics, frequency of consumption, species consumed, most important factors at the time of purchase, and the importance of the environment and traditions in their consumption choices. The survey was shared with universities, youth networks, associations, and personal and professional circles in all Baltic Sea countries. Descriptive statistics in tables and graphs were used to analyze the responses. Text analysis was used to summarize participants' comments. The median was calculated to establish the distribution and central value of participants' responses, who ranked 12 factors according to their degree of importance when making a purchase. Taste, product origin, and sustainable labels are the factors most participants consider when making a purchase. Tradition and local production ranked last. In conclusion, this study has covered the factors and preferences influencing consumer choice regarding fish and seafood. The patterns observed in the sample were similar to other larger-scale studies or European reports. Participants' age influenced their consumption frequency. Regarding taste, the product's origin and sustainable labels were the most often considered when purchasing. Traditions, although not considered at the time of purchase, influenced respondents’ fish and seafood consumption. Social factors often explain the sensory-affective motivational dimension or beliefs linked to consumption. A global understanding of consumers could guide institutions to strengthen their communication strategies. With more precise, practical, and consumer-targeted strategies, the Baltic Sea countries will ensure a collective sense of sustainable purchasing and eating and achieve the UN SDGs 12 and 14. / The Blue Food project
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Sweden's Path to NATO: Impacts on Security and Risk Perceptions : A comprehensive analysis based on the tactical, operative and strategic dimensions of Gotland / Sveriges väg till NATO: Effekter på säkerhet och riskOstrander, Hannah, Johansson, Amanda January 2024 (has links)
This Bachelor's thesis examines the consequences of Sweden's NATO membership regarding its security and defence policy, with a particular focus on Gotland. Sweden's transition to NATO membership was motivated by escalating geopolitical tensions in Europe due to the conflict between Russia and Ukraine and especially in the Baltic Sea region. This study employs a qualitative approach, using semi-structured interviews with key stakeholders in Gotland's military and municipal sectors to assess the strategic, operational and tactical effects of NATO membership. The results indicate that although NATO membership strengthens Sweden's national defence and geopolitical position, its immediate tactical and operational effects on Gotland are limited. The ongoing military development in Gotland, which was initiated before NATO membership, continues to develop with additional support and cooperation opportunities provided by the alliance. The research highlights the strategic necessity of NATO membership for Sweden, which provides increased security guarantees and adapts to broader geopolitical goals. However, the full extent of NATO's influence on Gotland's military development and societal impact requires further investigation given the recency of Sweden's membership on March 7, 2024. This thesis contributes to the academic discussion of geopolitical alliances and provides insights for policy makers in strategic planning and implementation.
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Low carbon hydrogen market outlook in the Baltic Sea region : The Baltic Sea Region Hydrogen Council ProjectJacobo Jara, Johans January 2024 (has links)
The European Commission's long-standing strategy to achieve climate neutrality by 2050 has rekindled enthusiasm for hydrogen as a key vector that could reduce emissions. The stakeholders in the European energy system have their full attention focused on this vector. Vätgas Sweden, as a market player together with other organizations, seeks through this research to understand the current outlook for the low-carbon hydrogen market in the countries of the Baltic Sea region and Ukraine, which would help to penetrate and strengthen economic and political ties within the European Union. I present insights based on information from 2022 and estimates of future hydrogen production and demand through 2035 within the geographic scope along with interview results from follow-up sessions with project member organizations. This enabled the identification of barriers and drivers for viable business development. The comprehensive global review of hydrogen projects up to May 2024 considered data on project phasing, hydrogen production technology, demand and installed production capacity through harmonized modelling and statistical inference. The analysis explores the main evidence on production technologies and methods of handling blue and green hydrogen to meet the Baltic Sea region's decarbonization targets, examining the potential for trade. I highlight the overlapping barriers and drivers in the hydrogen market of Denmark, Estonia, Finland, Germany, Lithuania, Latvia, Poland, Sweden and Ukraine. The considered analysis adds a more realistic estimation of hydrogen forecasts by showing a better picture of the context in the Baltic Sea region. Vätgas Sweden plans a series of projects and studies analysing European trends in low-carbon hydrogen production to provide stakeholders, specialists and scientists around the world with the current level of knowledge on the essential barriers and drivers in the period of its industrial emergence. / Europeiska kommissionens mångåriga strategi för att uppnå klimatneutralitet till 2050 har återuppväckt entusiasmen för väte som en nyckelvektor som kan minska utsläppen. Intressenterna i det europeiska energisystemet har sin fulla uppmärksamhet fokuserad på denna vektor. Vätgas Sverige, som marknadsaktör tillsammans med andra organisationer, söker genom denna forskning förstå de nuvarande utsikterna för vätgasmarknaden med låga koldioxidutsläpp i länderna i Östersjöregionen och Ukraina, vilket skulle bidra till att penetrera och stärka ekonomiska och politiska band inom Europeiska unionen. Jag presenterar insikter baserade på information från 2022 och uppskattningar av framtida väteproduktion och efterfrågan fram till 2035 inom det geografiska området tillsammans med intervjuresultat från uppföljningssessioner med projektmedlemsorganisationer. Detta gjorde det möjligt att identifiera hinder och drivkrafter för livskraftig affärsutveckling. Den omfattande globala översynen av väteprojekt fram till maj 2024 tog hänsyn till data om projektfas, väteproduktionsteknik, efterfrågan och installerad produktionskapacitet genom harmoniserad modellering och statistisk slutledning. Analysen undersöker de viktigaste bevisen på produktionsteknologier och metoder för att hantera blått och grönt väte för att uppfylla Östersjöregionens avkolningsmål, och undersöker potentialen för handel. Jag lyfter fram de överlappande barriärerna och drivkrafterna på vätgasmarknaden i Danmark, Estland, Finland, Tyskland, Litauen, Lettland, Polen, Sverige och Ukraina. Den övervägda analysen lägger till en mer realistisk uppskattning av väteprognoser genom att visa en bättre bild av sammanhanget i Östersjöregionen. Vätgas Sverige planerar en serie projekt och studier som analyserar europeiska trender inom vätgasproduktion med låga koldioxidutsläpp för att förse intressenter, specialister och forskare runt om i världen med den nuvarande kunskapsnivån om de väsentliga barriärerna och drivkrafterna under den industriella framväxtperioden. / La estrategia de larga data de la Comisión Europea para lograr la neutralidad climática para 2050 ha reavivado el entusiasmo por el hidrógeno como un vector clave que podría reducir las emisiones. Los actores del sistema energético europeo tienen toda su atención centrada en este vector. Vätgas Suecia, como actor del mercado junto con otras organizaciones, busca a través de esta investigación comprender las perspectivas actuales del mercado del hidrógeno bajo en carbono en los países de la región del Mar Báltico y Ucrania, lo que ayudaría a penetrar y fortalecer los lazos económicos y políticos dentro de la Unión Europea. Presento ideas basadas en información de 2022 y estimaciones de la producción y demanda futura de hidrógeno hasta 2035 dentro del alcance geográfico junto con los resultados de entrevistas de sesiones de seguimiento con organizaciones miembros del proyecto. Esto permitió identificar barreras e impulsores para el desarrollo empresarial viable. La revisión global integral de los proyectos de hidrógeno hasta mayo de 2024 consideró datos sobre las fases de los proyectos, la tecnología de producción de hidrógeno, la demanda y la capacidad de producción instalada a través de modelos armonizados e inferencia estadística. El análisis explora la evidencia principal sobre las tecnologías de producción y los métodos de manejo del hidrógeno azul y verde para cumplir los objetivos de descarbonización de la región del Mar Báltico, examinando el potencial para el comercio. Destaco las barreras y los impulsores superpuestos en el mercado del hidrógeno de Dinamarca, Estonia, Finlandia, Alemania, Lituania, Letonia, Polonia, Suecia y Ucrania. El análisis considerado añade una estimación más realista de las previsiones de hidrógeno al mostrar una mejor imagen del contexto en la región del Mar Báltico. Vätgas Suecia planea una serie de proyectos y estudios que analizan las tendencias europeas en la producción de hidrógeno con bajas emisiones de carbono para proporcionar a las partes interesadas, especialistas y científicos de todo el mundo el nivel actual de conocimiento sobre las barreras e impulsores esenciales en el período de su surgimiento industrial. / BaSeH2, Baltic Sea Region Hydrogen Network
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En merkantilistisk början : Stockholms textila import 1720–1738 / A Mercantilistic Beginning : The Import of Textiles to Stockholm 1720-1738Aldman, Lili-Annè January 2008 (has links)
<p>The purpose of this thesis is to, from an institutional approach, study how the Stockholm importers within the textile sector adapted their foreign trade to the change in economic policy 1720 through 1738. The focus is to investigate to what extent the introduction of new laws, regulations etc. can be an explanation for what happened to Stockholm’s foreign trade, mainly imports, particularly textile imports during the period. It is mainly the economic policies that had been enacted during the Hornian government and their effects that have been studied. This is a period that has seldom been studied in other research.</p><p>This thesis begins when the Russian raids were over. This was a year when the foreign trade still was relatively free and was untouched by the 17th century’s regulations. After 1721 the policies that would be introduced to increase Sweden's level of self-sufficiency and strengthen ties with the North Sea area had several components. Besides the economic policy, the main sources for the thesis are the city toll records.</p><p>The trade policies in the shape of tolls and fees, import and consumption bans etc. and the commercial policies together became different kinds of political tools used for several purposes. The conclusion of this thesis is that the economic policies made the Stockholm importers adapt their trade to the change. The import bans and sumptuary laws had an effect. The economic policies gave rise to an increase in the import of textile raw materials. The rise in toll costs and import fees contributed to displacing the foreign trade towards other areas. The change in the economic policies was successful in the sense that it gave rise to new conditions for domestic production within the textile sector and forced Stockholm's importers to adapt their foreign trade.</p>
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Massbalansmodellering av fosfor i ett åländskt kustområde : en utredning om lokaliseringen av Lotsbroverkets utloppsledningEklund, Jenny January 2004 (has links)
<p>This report is commissioned by the Water and Sewage Agency in The City of Mariehamn, Åland. The basic aim is to investigate positive or negative effects of a relocation of the sewage pipe from a wastewater treatment plant, Lotsbroverket. The environmental licence of Lotsbroverket is to be revised and The Environmental Appeal Board at Åland’s Government and Administrative Board has made demands that several possible locations in an outer water area should be examined. The present location of the sewage pipe is in Svibyviken, which has been classified as an “inner water area”.</p><p>The objective of this work is to study to which extent the nutrient loading from Lotsbroverket influence the environmental conditions in Svibyviken, and to investigate the suitability of different locations of the wastewater pipe from Lotsbroverket.</p><p>The way a coastal area looks, i.e., its morphometry, determines to a large extent its ecological characteristics. The investigated coastal area was digitalized from a nautical chart. The software used for this was Roots 3.3 and the GIS-tool ArcGIS 8.3. The localization of the coastal boundaries for the entire coastal area and for investigated sub-areas was determined according to the topographical bottleneck method, i.e., the boundary lines were drawn where the exposure of the coast to the open sea is minimized.</p><p>A process-based dynamic mass-balance model for total phosphorous has been used in this study. Using this model, one can estimate and quantify the effects of different nutrient sources in coastal areas. All the fluxes of phosphorous to, from and within the defined areas were studied and ranked. Model simulations have shown how changes in any of the phosphorous fluxes influence the mean monthly concentrations of total phosphorous. The situation for total nitrogen was determined with a statistical/empirical regression model between phosphorous and nitrogen concentrations. To estimate the expected ecological effects from a change in the nutrient loading from Lotsbroverket, statistical/empirical correlations between modelled nutrient concentrations and ecological effect variables have been used. Standard effect variables for the study of eutrophication effects in coastal areas are, e.g., the chlorophyll concentration, Secchi depth and oxygen saturation in deep water. These variables have also been used in this study.</p><p>It has been shown that (1) the nutrient concentrations of the Baltic Sea controls the concentration of nutrients in the studied areas to a very large extent, (2) that the nutrient fluxes from Lotsbroverket are small compared to the nutrient fluxes from the Baltic Sea and hence also of minor importance for the nutrient state of the receiving water system, (3) that the influence of the nutrient emissions from Lotsbroverket are most noticeable in the present inner recipient, Svibyviken, and (4) that the impact logically decreases with distance between the location of the sewage pipe and boundary line to the open sea. The overall conclusion is that no major improvement of the conditions in Svibyviken can be expected by a reduction or a relocation of the nutrient emissions from Lotsbroverket.</p> / <p>Detta examensarbete är ett uppdrag av VA-verket vid Mariehamns stad, Åland, med syfte att utreda effekter av en eventuell flyttning av avloppsreningsverket Lotsbroverkets utloppsledning. Inför en revidering av Lotsbroverkets miljötillstånd har Miljöprövningsnämnden vid Ålands landskapsregering ställt villkor på att tillståndshavaren skall utreda möjligheter till att avleda det renade avloppsvattnet till ett yttre vattenområde. Utloppsledningen mynnar i dagsläget i Svibyviken, vilken har klassificerats som ett inre vattenområde.</p><p>Målsättningen med detta arbete är att belysa vilka ekologiska effekter näringsämnesutsläppet från Lotsbroverket har på primärrecipienten Svibyviken samt att undersöka några andra områdens lämplighet som mottagare av avloppsvattnet. Ett kustområdes utseende och form, det vill säga dess morfometri, avgör i stor utsträckning dess ekologiska förhållanden. För att få en god bild av det undersökta områdets morfometri digitaliserades området utifrån ett sjökort i digitaliseringsprogrammet Roots 3.3, varefter data bearbetades med GIS-verktyget ArcGIS 8.3. Avgränsning av kustområdet som helhet och av undersökta delområden gjordes enligt den topografiska flaskhalsmetoden, det vill säga så att kustens öppenhet mot utanförliggande hav eller vattenområde minimeras (Håkanson et al., 1984; Pilesjö et al., 1991).</p><p>För arbetet har en processbaserad, dynamisk massbalansmodell för totalfosfor använts. Modellen har tagits fram för att eutrofieringseffekter i kustområden skall kunna studeras (Håkanson & Karlsson, 2001). Vid användandet av modellen kan effekter av olika näringsämneskällor uppskattas och kvantifieras. Samtliga totalfosforflöden till, från och inom olika avgränsade områden har studerats och rangordnats. Modellsimuleringar har visat hur förändringar i något av fosfortillflödena inverkar på recipientens månadsmedelkoncentration av totalfosfor. Situationen för kväve har undersökts med hjälp av en statistisk/empirisk regressionsmodell mellan fosfor- och kvävehalt. För att belysa de ekologiska effekter som kan förväntas efter en förändring av Lotsbroverkets fosfor- och kväveutsläpp har statistiska/empiriska kopplingar gjorts mellan näringsämneskoncentrationer och ekologiska effektvariabler. Bra effektvariabler vid undersökning av eutrofieringseffekter är exempelvis klorofyllhalt, siktdjup samt syrgashalt i bottenvattnet. Dessa variabler har också använts i detta arbete.</p><p>Resultaten visar att (1) närsaltskoncentrationerna i de studerade områdena i hög grad styrs av den allmänna eutrofieringsnivån i Östersjön, (2) att utsläppet av näringsämnen från Lotsbroverket inte inverkar på recipientens näringsstatus i någon stor utsträckning, (3) att Lotsbroverkets påverkan är störst på nuvarande recipient, Svibyviken, (4) och att påverkan sedan successivt minskar ju längre ut mot öppna havet utloppsledningen lokaliseras. Slutsatsen av utredningen är att en reduktion av Lotsbroverkets utsläpp eller nylokalisering av utloppsledningen inte kan förväntas ge någon omfattande förbättring av tillståndet i Svibyviken.</p>
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Fossiliserade frön för en bra Antropocen : Action-arkeologi för hållbarhet och miljö med förslag för applicering i svenska landskapLind, John January 2017 (has links)
This paper deals with issues on how archaeology might participate in transdisciplinary research andwork towards sustainable development. Three main themes are explored based on sustainabilitywork mainly from Stockholm Resilience Centre and previous archaeological texts about theutilisation of archaeology for environmental benefits. The themes are nature/culture-dichotomies,deep time perspectives and heritage. Each theme is continously adding unto the next one,whereafter applicability scenarios are discussed in three Sweden-specific environmental contexts:The Baltic Sea, agricultural landscapes and the alpine environment. Implications include: thedevelopment of a heritage perspective that bridges the nature-culture divide and focuses oncontinuity rather than preservation and includes human usage of heritage, possibilities forarchaeology to be used to inform environmental management and to counter NIMBY-ism
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Samspelet mellan ekologi, produktionsförhållande, politik och sociokulturella faktorer gällande Östersjöns torskbestånd från 1970-talet till 2003 / The interaction between ecology, state of production, politic and sociocultural factors applicated on the codpopulation in the Baltic Sea from 1970: s to 2003Peterson, Therése January 2004 (has links)
<p>The study begins with a historical background over the fisheries development in North America and in the Baltic Sea area in Finland and Sweden. As we can see the fisheries development depends on the interaction between ecology, state of production, politic and also social factors. In Sweden the fishery politic has changed over the period of the study. In the 1970: s the main politic focus was on the fisheries progress, expansion and rationalization. The State in Sweden took a vast part in this development and gave economic support. In the 1980: s the fishery politic in Sweden started to change and the environmental politics began to enter the fishery politic. The environmental problems in the Baltic Sea were given attention and it was a great anxiety over the eutrophication. In the 1980: s the codpopulation declined and with them the catches declined. The conflict over the White zone 1978-1988 between Former Soviet Union and Sweden resulted in a plunder fishery in the area east of Bornholm. This plunder fishery effected the cod population enormous and the effect has continued to the late 1990: s. </p><p>In 1995 Sweden joined the European Union and the common fishery politic replaced the Swedish fishery politic. </p><p>The system with TAC (Total Allowable Catch) is central in the common politic and it is used to control the cod catches. But the problem is that the TAC -volume has been higher than the codpopulation could stand. Despite the politic goal in Sweden and EU to preserve the codpopulation in the Baltic Sea, the codpopulation has continued to decline. The reason to this politic failure is that the limit of the ecology has been overseen. Instead, the economic and social values have been dominating the politic and together with a to weak control of the catches and environmental problems in the Baltic Sea, the situation for the cod has been devastating.</p>
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Biomethanation of Red Algae from the Eutrophied Baltic SeaBiswas, Rajib January 2009 (has links)
<p>In the semi-enclosed Baltic Sea, excessive filamentous macro-algal biomass growth as a result of eutrophication is an increasing environmental problem. Drifting huge masses of red algae of the genera <em>Polysiphonia</em>, <em>Rhodomela</em>, and <em>Ceramium</em> accumulate on the open shore, up to five tones of algae per meter beach. During the aerobic decomposition of these algal bodies, large quantities of red colored effluents leak into the water what are toxic for the marine environment. In this study, feasibility of anaerobic conversion of red algae <em>Polysiphonia</em>, rich in nitrogen and phosphorous, was investigated. Biogas and methane potential of <em>Polysiphonia</em>, harvested in two different seasons [October and March], was investigated through three different batch digestion experiments and laboratory scale CSTR [continuous stirred tank reactor] at mesophilic (37<sup>o</sup>C) condition. Autoclavation [steam and heat] and ultrasound pretreatments were applied in order to enhance the biodegradation. In STR, anaerobic codigestion of algal biomass with SS [sewage sludge] was applied with a gradual increase in organic loading rate [1.5-4.0 g VS/L/day] and operated for 117 days at 20days HRT [hydraulic retention time]. Reactor digestate was analyzed four times over the period to determine the nutrients and heavy metals content. It is concluded that the methane potential of algae harvested in October is almost two-fold than that of algae harvested in March, probably due to it’s higher [more than double] nitrogen richness. An increase in biogas yield was observed upto 28% and VS reduction was increased from 37% to 45% due to autoclave pretreatment. Ultrasound pretreatment had no effect on digestion. In batch digestion, maximum methane yield 0.25 m<sup>3</sup>/kg VS added at 273<sup>o</sup>K, was obtained from algae [harvested in October] pretreated in autoclave. Codigestion of algae with SS worked well in STR with a comparatively lower OLR. At a higher OLR, methanogens were inhibited due to increased VFAs accumulation and decreased pH. A maximum biogas yield 0.49 m<sup>3</sup>/kg VS added at 310<sup>o</sup>K , was obtained from algae [harvested in October] pretreated with autoclave. The methane content of the produced biogas was 54%. Average [over a short period, day 99-107, reactor showed steady performance] maximum biogas yields from untreated algae obtained 0.44 m3/kg VSadded at 310<sup>o</sup>K and the VS reduction was calculated 32%. Digestate, to be used as a fertilizer, was found NH<sub>4</sub>-N, N, P, K, S and Na rich and only Cadmium level was above the maximal limit among the heavy metals. The sand content in algae during harvesting was considered as a factor to disrupt the operation. Codigestion of <em>Polysiphonia</em> algal biomass with substrate with higher C:N ratio like paper mill waste should be more appropriate to increase the methane and biogas yield. It is inconclusive whether AD process is a good method to dewater redalgae or not but large scale harvesting of algae will definitely contribute to curb eutrophication of the Baltic Sea through decreasing N and P level.</p>
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Predictive Modelling of Aquatic Ecosystems at Different Scales using Mass Balances and GISGyllenhammar, Andreas January 2004 (has links)
<p>This thesis presents models applicable for aquatic ecosystems. Geographical Information Systems (GIS) form an important part of the thesis. The dynamic mass balance models focus on nutrient fluxes, biotic/abiotic interactions and operate on different temporal and spatial scales (site, local, regional and international). The relevance and role of scale in mass balance modelling is a focal point of the thesis.</p><p>A mesocosm experiment was used to construct a model to estimate the nutrient load of phosphorus and nitrogen from net cage fish farming (i.e., the site scale). The model was used to estimate what feeding conditions that are required for a sustainable aquaculture scenario, i.e., a zero nutrient load situation (a linkage between the site scale and the regional scale). </p><p>A dynamic model was constructed for suspended particulate matter (SPM) and sedimentation in coastal areas (i.e., the local scale) with different morphometric characteristics and distances to the Sea. The results demonstrate that the conditions in the Sea (the regional and international scale) are of fundamental importance, also for the most enclosed coastal areas.</p><p>A foodweb model for lakes was transformed and recalibrated for Baltic Sea conditions (i.e., the international scale). The model also includes a mass balance model for phosphorus and accounts for key environmental factors that regulate the presuppositions for production and biomasses of key functional groups of organisms. The potential use of the new model for setting fish quotas of cod was examined.</p><p>For the intermittent (i.e., regional) scale, topographically complex areas can be difficult to define and model. Therefore, an attempt was made to construct a waterscape subbasin identification program (WASUBI). The method was tested for the Finnish Archipelago Sea and the Okavango Delta in Botswana. A comparison to results from a semi-random delineation method showed that more enclosed basins was created with the WASUBI method.</p>
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