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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Insamlingssystemets påverkan på utsorteringsgrad och renhet av matavfall till biogasproduktion / The impact of the collection system on the degree of sorting and purity of food waste for biogas production

Johannes, Lundahl January 2018 (has links)
Produktionen av biogas är en viktig komponent för skapandet av ett fossilfritt samhälle. Rötning av det matavfall som uppstår i hushållen är en central källa till att producera biogas och biogödsel. Regeringen har satt upp etappmålet att till 2018 sortera ut minst 40 % av matavfallet från hushåll, storkök, butiker och restauranger så att energi kan utvinnas eller att 50 % av matavfallet samlas in så antingen energi kan utvinnas eller växtnäring tas till vara på.   Det här examensarbetet utfördes på initiativ av Tekniska verken i Linköping AB med syftet att studera och kartlägga hur olika fastighetsnära insamlingssystem för matavfall påverkar biogasproduktion med avseende på mängd och kvalitet på biogas och biogödsel. Det har dessutom studerats om det finns andra faktorer som påverkar insamlad mängd och renhet på matavfallet. Rapporten är tänkt att utgöra beslutsunderlag för Tekniska verken inför en eventuell omställning av rådande insamlingssystem.   Resultaten i studien visade att system där matavfall läggs i ett separat fack eller kärl har något högre utsorteringsgrad av matavfall jämfört med optisk sortering. Detta innebär att en omställning till fyrfackskäl eller separata kärl skulle kunna ge högre utsorteringsgrad än dagens optiska sortering. Därför konstateras det i studien att insamlingssystemet troligtvis har en påverkan på utsorteringsgraden av matavfall. Renhetsgraden är hög för samtliga studerade system, därför är det troligt att en omställning av insamlingssystem för villor i Linköping kommun kan genomföras utan att kompromissa med renheten på matavfallet. Det konstateras även i studien att det finns yttre faktorer som påverkar mängd och renhet på det matavfall som samlas från hushållen. Litteraturstudier och intervjuer med utvalda kommuner med hög utsorteringsgrad visade att faktorer som informationskampanjer och användarvänlighet kring matavfallsinsamling har en påverkan på insamlingsresultatet. Dock kan det inte bestämmas till vilken grad de yttre faktorerna påverkar resultatet.   För framtida studier rekommenderas att inkludera fler plockanalyser för att få en tydligare bild av hur resultatspridningen ser ut för de olika insamlingssystemen. Detta skulle leda till en större säkerhet i slutsatserna om hur de olika insamlingssystemen påverkar insamlingsresultatet för matavfall. Vidare är det möjligt att en strukturerad intervjustudie med fokus på enstaka utvalda faktorer skulle kunna avgöra vilken påverkan en isolerad yttre faktor har på insamlingsresultatet.
2

Lactobacillus spp. in honey bees of southwestern Sweden : A feasible gut-analysis via long-read 16S nanopore sequencing

Xinxo, Erik January 2022 (has links)
Together with other pollinating animals, honeybees maintain an ecological stability and pollinate both wild and cultivated plants, contributing to the preservation of natural ecosystems and overall security of food production. Unfortunately, honeybees across the world are dying at a dramatic rate, which is very dangerous for the biosecurity of this planet. The diversity of Lactobacillus species in the honeybee gut could be a direct indication of honeybee health. Among the objectives of this experiment was to characterize the diversity of Lactobacillus species in the gut of honeybees isolated from four geographically separate hives. This was achieved by extracting the DNA from the honeybee gut, amplifying the entire 16S rRNA marker-gene using the 27F and 1492R universal primers, and performing the full-length 16S nanopore sequencing workflow. Results confirmed the dominance of Lactobacillus in three out of four honeybee gut samples, with more than 70% of all reads mapping to Lactobacillus. The MinION analysis demonstrated, in high reproducibility with previous studies, that the honeybee gut microbiota consists of eight Lactobacillus species: Lactobacillus melliventris, Lactobacillus kimbladii, Lactobacillus mellis, Lactobacillus apis, Lactobacillus helsingborgensis, Lactobacillus kullabergensis, Lactobacillus mellifer, and Lactobacillus bombicola, shown to occur reliably in specific proportions. The findings reported here support the applicability of full-length 16S rRNA nanopore sequencing, and particularly of the portable MinION sequencing device, as an effective and relatively inexpensive method for analyzing Lactobacillus dominant microbiomes, such as the microbiome of the honeybee gut.
3

Algae Based Carbon Capture and Utilization feasibility study : - initial analysis of carbon capture effect based on Zhoushan case pre-study in China

Sen, Cong January 2012 (has links)
This pre-feasibility study was taken out by the co-operation with Zhejiang University, the CEU lab in Zhejiang University is taking researches of the algae based carbon dioxide capture technology, this report mainly aims to evaluate the GHG mitigation effect of this technology and give suggestions.   This study was carried out at Zhejiang University based on the Zhoushan islands waste incineration power plant project, the report presents the initial feasibility study for the algae based carbon capture and utilization technology focus on the carbon footprint and value summary . First the algae based CCU technology was introduced, then by using the life cycle assessment methodology and based on the description of the whole algae based carbon capture utilization process, each process unit was defined, concerning mass balance analysis was made for each unit, according to the mass balance analysis, carbon flow data was obtained for the whole process. In the discussion part, the carbon dioxide capture and avoid amount was analyzed, also the economic value summary for the material input and output was discussed. Concerning general suggestions for the further development and research about the project were given in five sectors: biotechnology, cultivation and harvesting, biomass utilization, substance and energy input, human resource.   The final conclusion is that the algae based carbon capture and utilization technology is not a carbon negative process, but could produce renewable fuels to avoid certain fossil fuels consumption. Lots of technical limitations exist in the study, it needs more work to applied this technology into reality for China. And the profit analysis based on the value summary for the project is optimistic without the consideration of the initial cost. The algae base CCU technology may become a useful alternative for the carbon abatement in China but not the best choice.
4

Energi‐ och miljöoptimering av  Lurbo ridanläggning

Johansson, Martina, Bellander, Ylva, Björklund, Isabelle, Dahlström, Julia, Selin, Lisa, Larsson, Emma January 2018 (has links)
Målsättningen med projektet var att miljö- och energioptimera Lurbo ridanläggning med avseende på deras egna miljömål som innebär att de siktar mot att bli den miljövänligaste ridanläggningen i Sverige. Det som har tagits i beaktande är solenergi, gödsel- och dagvattenhantering. Solenergi är idag den snabbast växande elproduktionskällan och ridanläggningen har enligt beräkningar (med hjälp av kalkylverktyget i Uppsala Kommuns solkarta, MATLAB och litteraturstudier) och observationer stora möjligheter till att implementera en solcellsanläggning för att motsvara deras elproduktionsbehov och mer därtill. Två åtgärdsförslag med två olika juridiska och ekonomiska utgångslägen presenteras i denna rapport, där en rekommendation slutligen ger ridanläggningen det mest gynnsamma beslutet att installera en solcellsanläggning som endast motsvarar deras årliga elbehov. Gödselproduktionen på ridanläggningen är stor och har därför en betydande miljöpåverkan. Näringsämnen läcker ut från både gödselplattan och från hagar. I denna rapport ligger fokuset på läckaget av fosfor, då läckaget från ridanläggningen överskrider tillåtna värden. Detta påverkar omgivningen och särskilt deneutrofierade Hågaån negativt. Aktuella åtgärder för att minska miljöpåverkan från gödselhanteringen presenteras. Enkla lösningar som att bygga ett tak över gödselplattan för att hindra läckage vid regn och att plantera fånggrödor läggs fram, men även mer kostsamma lösningar som att införskaffa en gödselbrännare har undersökts. Den viktigaste åtgärden för att minska fosforläckaget från hagarna anses vara att hålla hagarna fria från gödsel. För detta rekommenderas att investera i en gödseldammsugare. Ridanläggningen använder renat vatten för att bevattna ridhuset under sommarhalvåret. Genom att samla upp dagvatten för bevattning så kan kostnaden kraftigt reduceras samtidigt som bevattningen sker på ett mer miljövänligt sätt. Den mängd nederbörd som faller över anläggningens tak är tillräcklig för att täcka anläggningens bevattningsbehov. Hur uppsamlingen ska ske presenteras i fyra alternativa åtgärdsförslag i den här rapporten, där det förslag som är enklast att genomföra rekommenderas.
5

Gödsel som substrat vid biogasproduktion : Undersökning av biogas- och metanpotential i satsvisa laboratorieförsök

Lingmerth, Johanna, Jadstrand, Josefine January 2017 (has links)
I detta examensarbete har biogasproduktion med olika typer av gödsel som substrat, med fokus på hönsgödsel, undersökts genom satsvisa utrötningsförsök, BMP. I försöken undersöktes hur biogasutvecklingen såg ut över tid, den totala biogas- respektive metanpotentialen samt hur denna påverkas av tillsats av glycerol. Undersökningen visade att substratblandningar har större biogas- och metanpotential än enskilda substrat samt att tillsats av glycerol inte gynnar biogasproduktionen men kan gynna metanproduktionen. Undersökningen visade också att hönsgödsel har större biogaspotential, och högre metanhalt i den bildade biogasen, än nöt- och svinflytgödsel. / Superbiogödsel för ekologisk spannmålsproduktion
6

Energy recovery through anaerobic co-digestion of food waste and wastewater treatment sludge : A proposition of a water treatment and biogas plant for a floating island in Stockholm.

Bahena, Rodrigo January 2022 (has links)
The urge for more sustainable living motivated the Stockholm Tiny House Expo. The project aims to build a floating, sustainable, man-made island for living and working outside of Stockholm. This paper proposes a waste management method with possible energy recovery for the island. It introduces a comprehensive system that integrates decentralized wastewater treatment with energy generation through anaerobic treatment. A by-product of the wastewater treatment process, the sludge, is combined with food waste to generate energy through biogas. The island’s organic waste (wastewater and food waste) is thereby managed sustainably. The results of this report require further research. The energy supply from the biogas reactor was calculated to be 52.19 MWh. The wastewater treatment process was designed with an objective of 90% reduction of BOD5, to comply with the Swedish regulations for wastewater discharge to natural bodies of water, including the ocean. The system's total volume proposed is 11.25 m3, which is the sum of the volumes of all the reactors, or tanks, needed to complete the treatment.
7

Pollen identification using sequencing techniques

Kaur, Bimaljeet January 2022 (has links)
Palynology or the study of pollen, is essential understand the relationship between plants and their pollinators. Traditionally, pollen grains are identified by microscopy. The method has several shortcomings, such as being time-consuming and having low taxonomic resolution. DNA-barcoding-based sequencing can identify pollen at the genus and species levels without specialized paleontological expertise. Aim of this study is to assess which molecular approach can be the most effective tool and is the most cost-effective for the identification of pollen from mixed pollen samples. A DNA metabarcoding study was conducted using the rbcL barcode gene for pollen identification using two sequencing techniques: Sanger and MinION. DNA metabarcoding produced taxonomic data easily. For the analysis of Sanger and MinION sequencing data, BLAST and KRAKEN2 were used respectively. Pavian and KRONA were later used to visualize the MinION sequencing data. Various plant species native to Sweden were identified with this metabarcoding approach. However, the reference database failed to identify a few of them, thus indicating the need to expand the reference database.
8

Water & Cultivate

Alderhell, William, Norstedt, David January 2019 (has links)
No description available.
9

Bio-enhanced silicate weathering : Coupled to sequestration of CO2

Westholm, Marcus January 2022 (has links)
Weathering of silicate minerals has long been a known source of natural CO2 sequestration, that could be increased in the presence of microorganisms. Bio-enhanced weathering of silicate minerals could increase the sequestration of CO2 from the atmosphere.   The aim of this project was to evaluate the potential for a new Neutral emission technology (NET), using four different organisms, Aspergillus Niger, Knufia Petricola, Bacillus Subtilis and Cupriavidus Metallidurans and their potential to increase olivine weathering (dunite). Straw, manure and digestate was used as carbon sources. In total 9 biotic - and 9 abioitc reactors were made, containing a mixture of dunite and one of the three carbon sources. In total 250 mL of water was added to each reactor per week, for 6 weeks, and collected at the end of the week for analysis. Geochemical analyses of the leachate were performed, including pH, conductivity, alkalinity, total organic carbon (TOC), total inorganic carbon (TIC), cations, anions and three organic acids: citrate, acetate, and oxalate. Scanning emission microscope (SEM) was used to monitor potential differences pre- and post-treatment.   Straw reactors produced the most growth, both on the carbon source and the dunite grains. Likely due to the increased labile organic carbon concentrations. The total inorganic carbon and alkalinity demonstrated that inoculation of the reactors promoted weathering for all carbon sources, most significantly for the straw reactors. This observation was evidenced by etch pits in the SEM images and higher TIC, alkalinity, and magnesium values. Microbially enhanced silicate weathering has demonstrated it could be used for the development of NETs for the sequestration of atmospheric carbon. / BAM!
10

Microbial Fuel cells, applications and biofilm characterization

Krige, Adolf January 2019 (has links)
Since the 1900’s it has been known that microorganisms are capable of generating electrical power through extracellular electron transfer by converting the energy found organic compounds (Potter, 1911). Microbial fuel cells (MFCs) has garnered more attention recently, and have shown promise in several applications, including wastewater treatment (Yakar et al., 2018), bioremediation (Rosenbaum & Franks, 2014), biosensors (ElMekawy et al., 2018) desalination (Zhang et al., 2018) and as an alternative renewable energy source in remote areas (Castro et al., 2014). In MFCs catalytic reactions of microorganisms oxidize an electron donor through extracellular electron transfer to the anode, under anaerobic conditions, with the cathode exposed to an electron acceptor, facilitating an electrical current (Zhuwei, Haoran & Tingyue, 2007; Lovley, 2006). For energy production in remote areas a low cost and easily accessible feed stock is required for the MFCs. Sweet sorghum is a drought tolerant feedstock with high biomass and sugar yields, good water-use efficiency, established production systems and the potential for genetic improvements. Because of these advantages sweet sorghum stalks were proposed as an attractive feedstock (Rooney et al., 2010; Matsakas & Christakopoulos, 2013). Dried sweet sorghum stalks were, therefore, tested as a raw material for power generation in a MFC, with anaerobic sludge from a biogas plant as inoculum (Sjöblom et al., 2017a). Using sorghum stalks the maximum voltage obtained was 546±10 mV, the maximum power and current density of 131±8 mW/m2 and 543±29 mA/m2 respectively and the coulombic efficiency was 2.2±0.5%. The Ohmic resistances were dominant, at an internal resistance of 182±17 Ω, calculated from polarization data. Furthermore, hydrolysis of the dried sorghum stalks did not improve the performance of the MFC but slightly increased the total energy per gram of substrate. During the MFC operation, the sugars were quickly fermented to formate, acetate, butyrate, lactate and propionate with acetate and butyrate being the key acids during electricity generation. Efficient electron transfer between the microorganisms and the electrodes is an essential aspect of bio-electrochemical systems such as microbial fuel cells. In order to design more efficient reactors and to modify microorganisms, for enhanced electricity production, understanding the mechanisms and dynamics of the electron transport chain is important. It has been found that outer membrane C-type cytochromes (OMCs) (including omcS and omcZ discussed in this study) play a key role in the electron transport chain of Geobacter sulfurreducens, a well-known, biofilm forming, electro-active microorganism  (Millo et al., 2011; Lovley, 2008). It was found that Raman microscopy is capable of providing biochemical information, i.e., the redox state of c-type cytochromes (cyt-C) without damaging the microbial biofilm, allowing for in-situ observation. Raman microscopy was used to observe the oxidation state of OMCs in a suspended culture, as well as in a biofilm of an MFC. First, the oxidation state of the OMCs of suspended cultures from three G. sulfurreducens strains (PCA, KN400 and ΔpilA) was analyzed. It was found that the oxidation state can also be used as an indicator of the metabolic state of the cells, and it was confirmed that PilA, a structural pilin protein essential for long range electron transfer, is not required for external electron transfer. Furthermore, we designed a continuous, anaerobic MFC enabling in-situ Raman measurements of G. sulfurreducens biofilms during electricity generation, while poised using a potentiostat, in order to monitor and characterize the biofilm. Two strains were used, a wild strain, PCA, and a mutant, ΔOmcS. The cytochrome redox state, observed through the Raman spectra, could be altered by applying different poise voltages to the electrodes. This change was indirectly proportional to the modulation of current transferred from the cytochromes to the electrode. This change in Raman peak area was reproducible and reversible, indicating that the system could be used, in-situ, to analyze the oxidation state of proteins responsible for the electron transfer process and the kinetics thereof.

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