På grund av det stundande ökade elektricitetsbehovet vill Växjö Energi AB utreda möjligheter för utökad kapacitet för elektricitetsproduktion i samband med att ett av deras befintliga kraftvärmeblock börjar nå sin livslängd. En av de tekniker som Växjö Energi, genom detta examensarbete, granskar är Biomass fired Top Cycle. Denna teknik står företaget Phoenix BioPower AB för, där tekniken är specifikt inriktad på att kunna få ut ett högre elutbyte än vad befintliga kraftvärmeverk kan idag. Genom två olika scenarion, där ett Biomass fired Top Cycle block ingår, jämför arbetet bränsleförbrukning, värme- och elproduktion emot VEAB:s befintliga anläggning under ett år. I Scenario 1 var BTC-blocket i drift självt under sommarperioden, medan det i scenario 2 var avstängt och SV3 istället var i drift. Resultatet för de två scenariona visade på en stor ökning för elektricitetsproduktionen, men också en ökning för bränsleförbrukningen. Utifrån elektricitetsproduktionen och bränsleförbrukningen analyserades intäkter och kostnader för ett exempel år 2022. Arbetet konstaterar att välja mellan hög elektricitetsproduktion alternativt hög bränsleförbrukning är en komplex fråga, där både faktorer så som tillgänglighet på biomassa och världens energiläge läggs till.

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.

Over the past few decades, a growing interest in the thermal conversion of alternative fuels such as biomass and waste-derived fuels has been observed among the energy-producing companies. Apart from meeting the increasing demand for sustainable heat and power production, other advantages such as reducing global warming and ameliorating landfilling issues have been identified. Among the available thermal conversion technologies, combustion in grate-fired furnaces is by far the most common mode of fuel conversion. In recent years, Fluidized-Bed (FB) technologies have grown to become one of the most suitable technologies for combustion and gasification of biomass and waste-derived fuels.In spite of the benefits, however, some difficulties are attributed to the thermal conversion of the alternative fuels. Ash-related issues could be a potential problem, as low-grade fuels may include considerable concentrations of ash-forming elements such as K, Na, S, Ca, Mg, P, Si and Cl. These elements undergo many undesirable chemical and physical transformations during the thermal conversion, and often cause operational problems such as deposition-related issues, slag formation in furnaces, corrosion of the heat transfer surfaces, and bed agglomeration of the fluidized-beds. Ash-related problems in the utility boilers are a major concern that may result in decreased efficiency, unscheduled outages, equipment failures, increased cleaning and high maintenance costs.This thesis investigated the ash behavior and ash-related problems in two different FB conversion systems: a Bubbling Fluidized-Bed (BFB) boiler combusting solid waste, and a Dual Fluidized-Bed (DFB) gasifier using biomass as feedstock. Full-scale measurements, chemical analysis of fuel and ash, as well as thermodynamic equilibrium modeling have been carried out for the BFB boiler (Papers I-IV), to investigate the impact of reduced-bed temperature (RBT) and also co-combustion of animal waste (AW) on the ash transformation behavior and the extent of ash-related issues in the boiler. For the DFB gasifier (Paper V), a thermodynamic equilibrium model was developed to assess the risk of bed agglomeration when forest residues are used as feedstock.The experimental results showed that the RBT and AW co-combustion could decrease or even resolve the ash-related issues in the BFB boiler, resulting in a lower deposit-growth rate in the superheater region, eliminating agglomerates, and a less corrosive deposit (in RBT case). Thermodynamic equilibrium modeling of the BFB boiler gave a better understanding of the ash transformation behavior, and also proved to be a reliable tool for predicting the risk of bed agglomeration and fouling. The modeling of the DFB gasifier indicated a low risk of bed agglomeration using the forest residues as feedstock and olivine as bed material, which was in good agreement following the observations in a full-scale DFB gasifier.

Due to an increasing global population and changes in diets the impact of food consumption on the world’s ecosystems and their services has become more significant. The purpose of this project has been to investigate how the impact on ecosystem services from Swedish food consumption has changed over time and if this development is sustainable or not. A quantitative assessment of six different environmental impact factors has been carried out for each food category. The project clarifies how Swedish food consumption has developed since the 1960s, the origin of the food that has been consumed, which processes that affect the environment as well as the consequences from these impacts. The result showed that Swedish food consumption has increased considering quantity, that the consumption pattern has changed, and that the import of goods has increased since the 1960s. The average Swede eats more animal-based products such as meat, cheese and cream, along with more vegetable-based products such as fruit and berries, and vegetables. Instead, products such as milk and soured based products has decreased, while products made from flour and grains has stayed unchanged. The project shows that animal-based products, especially from ruminant animals, has a significantly higher ecological footprint in comparison with vegetable-based products, concerning most of the categories mentioned above. Considering that the swedes eat more animal-based products today than in the 1960sthefollowing conclusion, that the Swedish impact on ecosystem services has increased since the 1960s even though food production has become more efficient, could be drawn.

Nitrogen is the major component of biosphere. Paradoxically, nitrogen pollution is the concern globally. Ammonia pollution is due to its unceasing rejection into nature such as groundwater, current water and the atmosphere. This phenomenon constitutes a threat for the humanity, land and aquatic flora, and consequently disturbs the balance of natural ecosystem. Recently, that situation has lead to develop various techniques and/or technologies for ammonia removal from municipal and industrial wastewaters. Particularly in the environmental biotechnology area, two main objectives were recently aimed in many research activities: the development of new configurations of competitive bioreactors and the monitoring of partial nitrification process, which are the fundamental basis of this thesis project. In this study, the partial ammonium oxidation process, also called nitrite route, was studied in a 60 litre jet-loop submerged membrane bioreactor pilot plant. The research was organized around six chapters. An exhaustive literature review of the state-of- art of the biological nitrification process and the membrane technologies was performed. The materials and measurement methods were presented. The colorimetric method, the chromatography analysis, the biomass estimation by the suspended solids (SS), the aggregates size measurement, the gas holdup, the gas-liquid mass transfer, the bubbles gas diameter determination, the medium rheology aspects, etc., and the complete equipment of the bioreactor were studied in detail. The plant automation functioning was also studied. Membrane module (Mitsubishi Sterapore-L) characterization was carried out and three characteristic parameters were estimated: the membrane intrinsic resistance Rm, the membrane permeability Lp and the membrane porosity εm. Estimations revealed good agreement between experimental results and theoretical methods based on the Darcys law and the Carman-Kozeny law applicable in microfiltration system. Hydrodynamics and aeration aspects were studied. The mixing in the jet-loop system was characterized by the mixing time (tmix) and the circulation time (tc), respectively. The results showed that the characteristic times (tmix and tc) decrease with an increase in input gas flowrate and the circulated liquid flowrate. A model correlation involving the air and the combined liquid effects was proposed to describe the circulation time evolution. The classical non-steady state clean water test was used to determine the gas-liquid mass transfer coefficient (kLa). It was found to be influenced by the combined action of air and recirculated-liquid flowrates and a correlation has been proposed to describe their influence. The interpretation of kLa results and the system mixing data showed that the developed reactor corresponds to a near perfect mixing tank. This criterion was satisfactorily verified by literature data. The gas holdup (εg) was directly measured by the volume expansion method. In the absence of liquid circulation, εg ranged between 1 and 4% for the investigated range of gas liquid superficial velocities. It was found to increase linearly with the air superficial velocity, which corresponds to the bubbly flow regime. However, in the presence of liquid flowrate, εg slightly increased (from 1 to 6%) with increase in the superficial liquid velocity. A model has been proposed to correlate εg and the air and the recirculated-liquid velocities. The average diameter of the bubbles gas (dB) in the system was also estimated by the Leibson theoretical model based on the Reynolds number at the orifice of the gas distributor. Finally, biological aspects were studied. Respirometry measurements were conducted to characterize the process medium. The mass transfer, the gas holdup and the medium viscosity were determined. The obtained data allowed estimating the α factor and the β factor, respectively. The interaction of the growth of microorganisms into the process and the membrane performance was also investigated and a correlation model was proposed to describe membrane fouling with time. The optimal conditions for ammonium partial oxidation were determined using process monitoring and simulation. Dissolved oxygen (DO), temperature (T) and hydraulic retention time (HRT) were selected to achieve a high nitrite accumulation in the system. The results obtained showed that the selected parameters should be fixed at DO ≈ 2 mgO2.l-1, HRT ≈ 6 7 h and T = 30°C, respectively. The partial nitrification was simulated by the use of the TwoPopNitrification model included into the BioWin 2.2 software. For these simulations, a sequencing ammonia oxidation assumption was adopted: the nitrozation followed by the nitration step, respectively. The corresponding kinetics and stoichiometric constants were estimated by combining literature data and experimental nitrification results. For these estimates, the ammonium oxidation was monitored on several process samples taken at different times. The estimates were also delivered by monitoring the ammonium oxidation on the process operated in the batch mode. The plotting of simulations and experimental results revealed good agreement. In order to investigate the process performance in terms of biological stability, a long time period (≈ 600 days) was simulated. The results showed that a high stable nitrite accumulation (> 95%) could be achieved when the above optimal conditions are imposed to the system. However, after a long time, the accumulated nitrite is converted into nitrate and then the system is disrupted. For the simulated experimental conditions, the process disruption period was located between 180 and 350 days. At this period, a corresponding theoretical purge flowrate was found to range between 0.15 10-3 m3.d-1 and 3.0 10-3 m3.d-1. Simulations also showed that increasing the purge flowrate decreases the sludge retention time and then favours nitrite accumulation into the process. That is an interesting strategy to increase the performance of the biological partial nitrification process.

Studies in Europe, Japan, and North America have reported that wild fish exposed to treated sewage effluents can exhibit significant physiological and reproductive abnormalities consistent with exposure to hormonally active chemicals. The main objective of this research project was to examine the estrogenic and androgenic activity in treated sewage to determine the risk associated with treated sewage discharges in Australia and New Zealand. Several bioassays, including a sheep estrogen receptor and a rainbow trout androgen receptor binding assay, were set up and validated with model compounds. The assays were then used to measure the estrogenic and androgenic activity in sewage samples from 15 municipal sewage treatment plants (STP) utilizing a variety of treatment technologies. Raw sewage samples contained high levels of both estrogenic and androgenic activity, up to 185 ng/L estradiol equivalents (EEq) and up to 9330 ng/L testosterone equivalents (TEq), respectively. Secondary treatment processes such as activated sludge had the greatest impact on removal of biological activity from the wastewater. The estrogenic and androgenic activity in final treated effluents were <1 to 4.2 ng/L EEq and <6.5 to 736 ng/L TEq, respectively. Based on lowest observable effective concentrations reported in the literature, these levels are unlikely to induce biological effects in exposed fish in the short term. To examine potential long-term effects, resident mosquitofish chronically exposed to undiluted treated sewage were sampled. Several morphological biomarkers indicative of endocrine disruption were measured and compared with mosquitofish captured at a reference site. Mosquitofish captured in a constructed wetland for tertiary treatment of secondary treated sewage exhibited morphological differences such as elongated anal fins consistent with exposure to androgenic chemicals, although this effect was not measurable in fish collected at sites further downstream or at any of the other sites. Based on these results, it is unlikely that mosquitofish populations would be significantly affected by exposure to final treated sewage. A reverse transcription real-time polymerase chain reaction (RT-PCR) method to measure the production of a female-specific protein (vitellogenin) mRNA in adult male mosquitofish was developed, and this could be used as a rapid test to detect early changes in individuals exposed to estrogenic activity.

<p>Zein is a major storage protein of corn, with unique amphiphilic film forming properties. It is insoluble in water, but soluble in 70% ethanol and acetic acid, and has been declared ‘generally recognized as safe’ (GRAS) by the FDA. Due to new advances in food nanotechnology, zein is being investigated for various applications such as biodegradable packaging, oral delivery of proteins and peptides, scaffold for tissue engineering, as well as biodegradable sensor platforms. The time consuming and highly complicated methods for toxin and allergen analysis in the food industry necessitates the need for a rapid, selective, compact and easy-to-use method of detection for analytes. In the scope of this dissertation, we investigated the feasibility of functional zein nanocomposite films and formation of a zein nanocomposite sensor assembly for rapid and highly selective electrochemical measurements of food toxins and allergens. Fabrication of a zein based electrochemical amperometric sensor assembly was studied, first through the comparison of various zein film characteristics changes with the application of Laponite®, graphene oxide and carbon nanotube nanoparticles, followed by a proof-of-concept study by detecting the gluten allergen protein gliadin. </p> <p>To mechanistically study the functional zein nanocomposite films, Laponite®, a silica nanoparticle, was added in the presence of 70% ethanol solvent and oleic acid plasticizer. The films were studied using various characterization techniques like transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), water contact angle measurements etc. Through Si-N bond formation between Laponite® and zein, fabricated zein nanocomposite films showed increase in surface hydrophobicity, water vapor barrier properties, tensile strength and Young’s modulus. Graphene oxide (GO), a carbon nanoparticle, was also incorporated into zein through the solvent casting process. Uniform dispersion of GO nanoparticles within zein matrix were confirmed up to 1% GO loading, and covalent and hydrogen bonding mechanisms were proposed. Similar to zein-Laponite® (Z-LAP) nanocomposites, zein-GO (Z-GO) showed increase in hydrophobic tendencies, rougher surface and a 300% improvement in Young’s modulus and 180% improvement in tensile strength at only 3% GO loading. Both nanoparticles increased tensile strength, thermal stability and water vapor barrier property of the films, indicating a potential for food packaging as an alternative application for the nanocomposite films.</p> Finally, the research focused on the fabrication of an electrochemical amperometric sensor, capable of detecting the protein gliadin, which is responsible for the allergic reaction with people having celiac disease. Novel biodegradable coatings made from zein nanocomposites: zein-graphene oxide, zein-Laponite® and zein-multiwalled carbon nanotubes (Z-CNT) using drop casting technique were tested for fabricating the electrochemical sensors using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV) techniques. As Z-CNT produced the strongest signals compared to other nanomaterials, the active tip of the electrochemical sensor was functionalized through a sequence of layer by layer deposition of Z-CNT nanocomposite, antibody and target analyte. Here, Z-CNT acts as a natural linker molecule with large number of functional groups, that causes immobilization of capture antibody and target, to ensure high sensor performance. Both CV curves and SWV curves indicated successful sequential immobilization of gliadin antibody onto the Z-CNT coated electrode. The Z-CNT biosensor was successfully able to give CV signals for gliadin toxins for as low as 0.5 ppm and was highly specific for gliadin in the presence of other interfering molecules, and remained stable over a 30-day period. The low-cost, thin, conductive zein films offered a promising alternative for protein immobilization platforms used in sensors and can be extended to other matrices in biosensors as well as other functional film applications

Humans are increasingly influencing the climate and the temperature of the Earth by burning fossilfuels, destroying forests, and raising livestock. This adds massive amounts of greenhouse gases(GHG) to those already present in the atmosphere, amplifying the greenhouse effect andcontributing to global warming. The building sector accounts for a significant amount ofgreenhouse gas emissions. Decarbonizing the building industry can result in significant emissionreductions in the future years. Sweden's energy and climate goals have been updated, and some ofthem include reducing GHG emissions in the building sector, increasing energy efficiency, andmaking electricity production 100 percent renewable. In Sweden, energy renovations in singlefamily houses (SFHs) have the potential to reduce GHG emissions and improve energy efficiency,but the rate of energy renovations remains low because of financial, social, and behavioral barriers.This thesis aims to use LCA and LCC methodologies to assess energy renovations on SFH inVäxjö by combining various combinations of energy efficiency measures (EEMs) to reduce energyuse. The energy performance and eight different renovation scenarios using different EEMs havebeen evaluated for the selected single-family building. To evaluate building renovation measures,we developed a method based on life cycle assessment (LCA) and life cycle cost (LCC) thatincorporates building information modeling (BIM). Five different renovation measures werecombined in eight scenarios in this research, including different thicknesses of thermal insulationfor walls and roofs, triple-glazed windows, and doors with different U-values, air-source heatpumps, mechanical ventilation with heat recovery, and solar photovoltaic. The present cost valuesof renovation measures over 50 years for LCC calculation were calculated. The global warmingpotential (GWP) of each renovation measure was estimated over 50 years using One-click LCA.According to the findings of this thesis project, scenarios 1 and 8 had the lowest and highestreductions in primary energy number, respectively. Scenarios 5, 6, 7, and 8 are the most costeffective in comparison to other scenarios. All scenarios resulted in a reduction in GWP impactfrom an LCA perspective in which scenario 7 resulted in the highest reduction in GWP impact.

Access to fresh water is a human right, yet more than 780 million people, especially in rural areas, rely on unimproved sources and the need for finding ways of treating water is crucial. Although the use of natural coagulant protein in drinking water treatment has been discussed for a long time, the method is still not in practice, probably due to availability of material and limited knowledge. In this study, about hundred different crude extracts made from plant materials found in Southern India were screened for coagulation activity. Extracts of three Brassica species (Mustard, Cabbage and Cauliflower) were showing activity comparable to that of Moringa oleifera and were further investigated. Their protein content and profile were compared against each other and with coagulant protein from Moringa. Mustard (large) and Moringa seed proteins were also studied for their effect against clinically isolated bacterial strains. The protein profiles of Brassica extract showed predominant bands around 9kDa and 6.5kDa by SDS-PAGE. The peptide sequence analysis of Mustard large identified the 6.5kDa protein as Moringa coagulant protein (MO2.1) and the 9kDa protein band as seed storage protein napin3. Of thirteen clinical strains analysed, Moringa and Mustard large were proven effective in either aggregation activity or growth kinetic method or both in all thirteen and nine strains respectively. To my knowledge this is the first report on the presence of coagulant protein in Brassica seeds. Owing to the promising results Brassica species could possibly be used as a substitute to Moringa coagulating agent and chemicals in drinking water treatment. / <p>QC 20121214</p>

Solar energy industries are one of the fastest-growing industries in the global energy market. Between 2018 and 2019, installed capacity in Sweden increased by 70%. This is due to a combination of declining PV module and inverter costs, as well as  increased conversion to fossil-free energy production to mitigate greenhouse gas emissions. In fact, solar PVs have a 25-year life span, and soon many deployed PVs would soon reach their end of life (EoL), it is, therefore, important to organize for the EoL of PVs in order to recover precious resources and recycle PV modules in a sustainable manner. Currently, less than 10% of global solar cell waste is recycled, due to the lack of incentives for recycling in most countries. In the European Union, used-up modules are governed by the WEEE (Waste Electrical and Electronic Equipment) Directive, which requires the collection of 85% of solar cell waste, with at least 80% of the waste being prepared for reuse or recycling. Solar cell waste has not amounted to significant volumes in Sweden, due to the lack of no known systems for recycling. Used-up modules are currently collected and managed as electronic waste in one of two approved collection systems in Sweden. The aim of this thesis is to analyze and assess methods of recycling waste solar panels in Sweden and is it economically viable to set up a solar waste recycling center before it reaches the right amount of waste. Moreover, the main focus is on the analysis and comparison of the environmental impacts of various recycling methods for crystalline silicon (c-Si) and cadmium telluride (CdTe) panels. To recycle solar panel waste, the elements of these panels must be assessed from both an economic point of view as well as environmental impacts. Today, the most common PV panels in the global market and also Sweden are c-Si and CdTe types. The results showed except for the pyrolysis method, the environmental impacts of both c-Si and CdTe PV panels from the thermal-based recycling methods, are lower than chemical methods. Furthermore, the extraction of Al, Si, and glass from c-Si and the extraction of glass from CdTe has a less environmental impact than the current techniques used in the recycling of PV panels. Finally, in this study, we revealed which materials can be prioritized for maximum economic and environmental advantages from recycling. In c-Si modules, these are Ag, Al, Si, and glass and in CdTe modules, these are Te, Cu, and glass. Currently, investing in a new solar module recycling center in Sweden is not economically viable. Because the possibility of such an investment requires economic and political incentives. Given that by 2042 the volume of Swedish solar waste will not reach the minimum level of profitability to build a new specialized center for the recycling of solar modules, the best decision is to modify the existing plants in Sweden to recover expensive and vital materials.