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  • 1.
    Aldaron, Mattias
    Karlstad University, Division for Engineering Sciences, Physics and Mathematics.
    Anaerob rening vid StoraEnso Skoghalls Bruk2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    An analysis of a specific application of anaerobic wastewater treatment at a pulp and board mill, Stora Enso Skoghall, was carried out. A literature study was done and effluent wastewater from CTMP pulp production was analyzed. The analysis consisted of a broad constituent analysis and an anaerobic treatment trial. Results from these test where used to calculate the treatment effectiveness and resulting energy potential at the mill.

    The literature study and constituent analysis showed that toxicity of the water to be treated, due to wood extractives and sulphur content, was of concern. Detoxification chemicals targeting these constituents where used in the anaerobic treatment trial. The trial consisted of a two chamber upflow reactor and aerobic post treatment. The result of the trial is that the water of concern has about 50% anaerobically degradable content. A full scale implementation of anaerobic wastewater treatment would result in a methane production of 3,76 to 7,76 GWh/yr. An application of anaerobic wastewater treatment will also result in electricity savings, in aerated pond, and increase the capacity margin on current sludge handling techniques.

  • 2. Andersson, Johan
    Energieffektiv torkning av blåmusslor2013Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
  • 3.
    Brici, Ecaterina
    et al.
    Karlstad University, Faculty of Technology and Science.
    Bergstedt, Ksenia
    Karlstad University, Faculty of Technology and Science.
    Kemisk modifiering av avloppsvatten för effektivare syresättning2006Independent thesis Basic level (professional degree), 15 points / 22,5 hpStudent thesis
    Abstract [en]

    Biological wastewater treatment processes consume large quantities energy in the aeration processes. The biological treatment is responsible for 80 % of the total consumption of electricity and thereby responsible for the biggest part of the energy costs. Today when the energy prices increase the energy efficiency of the wastewater treatment is a question of high priority.

    The aim with this study is to study oxygen transfer in to the wastewater from paper industry with the intention to make the biological wastewater treatment more energy efficient. Studies are limited to wastewater from Gruvöns mill.

    The study has been carried out in lab scale. The oxygenation has been conducted by using a surface aerator of the type airTURBO from Eden Aquatech. The company strives for innovative technology for aeration, oxygen involvement and mixing of waters. This company is interested to further develop technology for these processes and to make products more energy efficient.

    The study was carried out with clean water, industrial wastewater and modified industrial wastewater. The modification of industrial wastewater has been done by adding salts and by changing the pH.

    It is realized that chemical modification of wastewater by adding salts has important impact of the aeration. The addition of salts into wastewater results in a reduction of energy consumption for the aeration.

    Quantification of energy consumption for aeration has been carried out.

    The quantification shows a reduction of 17% for aeration of chemical modified wastewater with salts compared to unmodified wastewater.

    To modifying wastewater by raising pH-value to 11 shows no positive impact on the system, it requires more energy.

  • 4.
    Forsberg, Åsa
    Karlstad University, Faculty of Technology and Science.
    Energieffektivisering i ett verkstadsföretag: En analys av energibesparande åtgärder samt uppvärmnings- och kylsystems driftkostnader och koldioxidutsläpp2010Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    The energy use in a workshop company has been examined in this work in order to find areas for energy efficiency improvement. The combined oil and electricity heating in the company were compared with other alternative heating systems including cooling of the premises in following combinations:

    1. Ground source heat pump for heating and cooling
    2. District heating and absorption cooling
    3. District heating and low temperate surface water cooling

    Energy use, operation costs and carbon dioxide emissions were calculated for the current heating systems and the three alternatives including cooling. The ground source heat pump for heating and cooling decreases bought energy with 34 MWh annually compared to current heating only. The district heating and low temperate surface water cooling has the largest reduction of operation cost and carbon dioxide. The operation cost decreases with 42 kSEK and the carbon dioxide with 43 metric ton CO2 annually. The differences between the alternatives were smaller concerning the operation costs. The ground source heat pump alternative had smaller reductions of carbon dioxide than the other two alternatives with district heating.

    An alternative heating and cooling system can also lead to alternative energy use. The choice is between electrical or heat energy. A weighting can be done to evaluate the energy use for heating on basis of how much energy is needed in order to generate the energy the end user buys. A 2.5 factor for electrical energy entails the alternative with district heating and low temperate surface water cooling gets the lowest heating and cooling energy in comparison.

    An inventory of the lighting was also done. The company has already an energy effective lighting but yet another saving of 2 MWh can be done annually without replacement of armatures.

    Finally, the operation time of the compressor was calculated with a mean value of 11 hours per day. The compressor delivers pressure air to machines and tools. There can be a great demand for pressure air in the workshop but the operation time can also be an indication of leakage in the air net.

  • 5.
    Govindarajan, Venkatesh
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Pinch analysis, as a technique for optimising resource utilisation and promoting environmental sustainability: A review of recent case studies from the developing world and transition economies2019In: Resources Environment and Information Engineering, ISSN 2661-3131, Vol. 1, no 1, p. 1-17Article in journal (Refereed)
    Abstract [en]

    Pinch analysis, as a technique to optimise the utilisation of resources, traces its beginnings to the 1970s in Switzerland and the UK – ETH Zurich and Leeds University to be more precise. Over four decades down the line, this methodology has entrenched itself in research circles around the world. While the technique was developed, to begin with, for energy (heat) recovery, it has since then expanded to embrace several other fields, and enabled optimisation of resource utilisation in general. The motive behind this article is to perform a focused, selective review of recent case studies from the developing world and transition economies, having ‘pinch analysis’ in their titles and thereby as their ‘core, crux and gist’, during the period 2008-2018. The resources focused on, include heat energy, electrical energy, water, solid waste, money, time, land (surface area), storage space (volume), human resources, mass of resources in general and hydrogen, while a handful of publications have their focus on carbon dioxide (greenhouse gases in general) emissions. Multi-dimensional pinch analysis promises to be an effective tool for sustainability analysis in the years to come; most importantly in the developing world where social well-being and economic development are priorities in the years ahead, and they ought to be attained by a simultaneous truncation of the environmental footprint, in other words, an optimisation of resource utilisation as well as adverse environmental impacts. In other words, the focus ought to be on sustainable production (efficiency) and consumption (sufficiency). 

  • 6.
    Govindarajan, Venkatesh
    et al.
    Norwegian University for Science & Technology, Norway.
    Dhakal, Shobhakar
    Natl Inst Environm Studies, Global Carbon Project, Tsukuba, Ibaraki, Japan.
    An international look at the water-energy nexus2012In: Journal of American Water Works Association, ISSN 0003-150X, Vol. 104, no 5, p. 93-96Article in journal (Other (popular science, discussion, etc.))
  • 7.
    Granberg, Johan
    Karlstad University, Faculty of Technology and Science.
    Material- och energiåtervinning av kuvert: Scenarioanalys2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recycling and incineration are two ways to deal with waste. Generally, paper recycling has lower carbon dioxide emissions than incineration of paper. Envelope is a paper product that is not included in any producer responsibility and the pulp and paper industry recommends consumers not to sort envelopes in the paper recycling container, since envelopes contain substances that can be a source for stickies. An argument against recycling is that problems caused by stickies increases costs for the companies that produces paper from waste paper. The Swedish market has envelopes that, when they are processed in the paper mill, do not develop stickies, namely envelopes tagged with Svanen. The purpose of this paper is to find the most suitable way to deal with envelopes. The aim of this study is to find the net energy consumption for recycling and incineration of envelopes. Four scenarios were investigated; all envelopes are incinerated, all envelopes are recycled, only envelopes tagged with Svanen are recycled, all envelopes are replaced with envelopes tagged with Svanen and are recycled. The results are not unanimous. Replacing all envelopes with envelopes tagged with Svanen is the scenario with lowest net energy consumption, presupposed paper recycling is to prefer before paper incineration.

  • 8.
    Granström, Karin
    Karlstad University, Division for Engineering Sciences, Physics and Mathematics.
    Emissions of volatile organic compounds from wood2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The central aim of this thesis is to support the efforts to counteract certain environmental problems caused by emissions of volatile organic compounds.

    The purpose of this work was (1) to develop a method to establish the amount of emitted substances from dryers, (2) to determine the effect of drying medium temperature and end moisture content of the processed material on emissions of monoterpenes and other hydrocarbons, (3) to examine the emissions of monoterpenes during production of pellets, and (4) to examine the natural emissions from forests with an eye to implications for modelling.

    The measurement method (1) resolves the difficulties caused by diffuse emissions, and also solves the problems associated with high moisture content of the drying medium. The basic idea is to use water vapour to determine the exhaust flow, while a dry ice trap is used both to preconcentrate emitted volatile organic compounds and to determine the moisture content of the drying medium. The method as used in this paper has an uncertainty of 13% using a 95% confidence interval.

    Emissions from a spouted bed (2) in continuous operation drying Norway spruce sawdust at temperatures of 140°C, 170°C or 200°C was analysed with FID and GC-MS. When the sawdust end moisture content was reduced below 10%wb, emissions of terpenes and volatile organic compounds per oven dry weight increased rapidly. Increased temperature of the drying medium increased the amounts of emitted monoterpenes when sawdust moisture content was below the fibre saturation point.

    Examination of sawdust and wood pellets from different pellets producers (3) revealed that most of the terpene emissions happened during the drying step, with rotary dryers causing higher emissions than steam dryers. Almost all of the volatile terpenes remaining in wood after drying were released during pelleting. When sawdust with higher moisture content was used in the pellets press, the terpene emissions were increased.

    Terpenes emitted naturally from vegetation can have an adverse environmental impact. Factors affecting terpene emissions from tree species in Sweden were reviewed (4). Models for prediction of terpene fluxes should include not only temperature but also light intensity, seasonal variation, and a base level of herbivory and insect predation. Prediction of high concentrations of ambient terpenes demand sufficient resolution to capture emission peaks e.g. those caused by bud break.

  • 9.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science.
    Utvärdering av miljöanpassat reningsverk i Hammarö kommun ur ett kretsloppsperspektiv: förstudie för etablering av nollpunkt2005Report (Other (popular science, discussion, etc.))
    Abstract [en]

    The Hammarö municipality in the region Värmland is building a wastewater plant for both wastewater and organic household waste.  The aim is to create an ecologically sustainable system for the local recycling of wastewater and organic household waste.  The plant is based on biological purifying processes, and outflows are treated in a constructed wetland.  The sludge is treated in a wet compost and in a bed of reeds.  Phosphorous will be collected and used for fertilizer.  The net result is expected to be a decreased nutrient load to the recipient.  Hammarö have a major town (of 12 000 people) with central water and wastewater facilities.  The new plant is to serve scattered villages and cottage summer houses.  The performance of existing private wastewater treatments is in many cases unsatisfactory, and with the ground at Hammarö characterized by cliffs, thin layers of dirt, and moraine, the prospects for wastewater purification through infiltration is not good.  The aim of this report is to calculate the current situation regarding the flows of nutrients from private wastewater treatments, and the transport work of organic garbage and waste.  This to establish a baseline from which to judge the size of coming improvements.  From households in the eastern part of Hammarö, where households are to be connected to the new wastewater plant, leaks 2100 kg nitrogen and 370 kg phosphorous to the environment, whereas 930 kg nitrogen and 120 kg phosphorous is transported to the municipality's existing wastewater facility.  Transports amounts to 21000 km annually, distributed as 3900 km/year for organic garbage, 480 km/year for latrine, 5700 km/year for sludge and 11000 km/year for closed tanks.

     

  • 10.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science.
    Utvärdering av miljöanpassat reningsverk i Hammarö kommun ur ett kretsloppsperspektiv: minskning av transportarbete och näringsläckage2007Report (Other (popular science, discussion, etc.))
    Abstract [en]

    Hammarö municipality has a new wastewater treatment plant with biological purifying processes. It processes both wastewater and organic household waste. The aim of this report is to calculate the impacts on transports and nutrient leakage of connecting different villages to this plant. The use of garbage mills to transport organic household waste in sewers has not yet caused a noticeable decrease in the amount of household garbage collected, as only 35% of the households have installed a mill. If this percentage persists in existing houses, but mills are made mandatory in planned new villages, the nutrients lost through incarnation of household waste will decrease with 54%. Before the new plant was in operation, sludge was transported by vehicles. The transport load was 12600 km/year. This will decrease to 5500 km/year when the villages Rud and Torp are connected to the plant, to 3000 km/year when the easternmost parts of Hammarö are connected, and cease completely when the village Tynäs is connected. A fully constructed sewerage system on eastern Hammarö will cause a reduction in transports by 60%, which will save almost 7000 liters of fuel a year. When households in Rud and Torp are connected to a wastewater purification plant, their previous leakage of 1080 kg nitrogen and 190 kg phosphorous will cease. Connection of the easternmost parts of Hammarö will remove leakage of 480 kg nitrogen and 85 kg phosphorous, and connection of Tynäs will remove an additional 542 kg nitrogen and 95 kg phosphorous.

  • 11.
    Guerra Garlito, Rebeca
    Karlstad University, Faculty of Technology and Science.
    The water treatment system at Djupdalen2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    This is a project about The Water Treatment System at Djupdalen. The leakage water comes to the Water Treatment System from a deposition plant through the land. The leakage water is characterized by a high concentration of nitrogen and the system is based on biological removing of the nitrogen in the water, by nitrifying and denitrifying bacteria. Four different problems are found in the system: 1. High level of nitrogen concentration in the outgoing water of the system. It should be due to the lack of phosphate in the water, that do not let the bacteria to grow. 2. Low temperature during the most part of the year. Nitrifying and denitrifying bacteria are temperature-dependent, that are very slow at low temperatures. 3. High oxygen concentration in one of the anoxic pond, where the denitrification process take place. This oxygen concentration is too high for denitrifying bacteria to work. 4. The nitrification and denitrification bacteria need to be “old” to work efficiently. They need a surface to attach, because if not they flow with the water and they leave the system. And four possible solutions for the system are presented: 1. Phosphate should be added to the system to let bacteria growth. 2. Store the water at a store pond during the winter months and transport it to the system when the temperature is optimum for the bacteria to work. 3. Add carbon matter to improve the carbon oxidation and to low down the oxygen levels at the anoxic ponds. 4. Two options are presented to improve the system, the first one is based on the construction of a dark wavy bottom in the channel system, which will give a surface for bacteria to attaché, it will produce oxygenation in the water, and it will also improve the water temperature; and the second one is based on the addition of panels made of black material, which will give to bacteria a surface to attach, and improve the water temperature.

  • 12.
    Gustafsson, Fredrik
    Karlstad University, Division for Engineering Sciences, Physics and Mathematics.
    Gasturbinventil2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 13.
    Haas, Jan
    et al.
    KTH, Geodesi och geoinformatik.
    Ban, Yifang
    KTH, Geodesi och geoinformatik.
    Remote sensing of bidecadal urbanization and its impact on ecosystem service in the yangtze river delta2013In: Proceedings of Dragon 2 Final Results & Dragon 3 Kick-Off Symposium: 25-29 June 2012, Beijing, P.R. China, ESA Communications , 2013, p. 1-8Conference paper (Refereed)
    Abstract [en]

    The degree of urbanization and resulting effects on Ecosystem Services is investigated in the Yangtze River Delta in China within a 20 year time frame from 1990 to 2010. A Random forest classifier is used to classify the Landsat mosaic from 1990 and the HJ-1A/B mosaic dating from 2010. Urban Land Index (UI) and Urban Expansion Index (UX) are used to represent the intensity and rapidity of urbanization. Post-Classification Change Detection is then performed and Ecosystem Service value losses for the land-cover classes water, wetland, forest and cropland that transitioned to urban areas are calculated according to a valuation scheme adapted to the Chinese market. The results showed that Yangtze River Delta experienced significant urbanization during 1990 to 2010. Urban areas increased alongside a major decrease in cropland resulting in a substantial loss of 4.2 billion CNY in Ecosystem Services.

  • 14.
    Henriksson, Lisa
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Frodeson, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Berghel, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Andersson, Simon
    Emerging Cooking Solutions Sweden AB.
    Ohlson, Mattias
    Emerging Cooking Solutions Sweden AB.
    Bioresources for Sustainable Pellet Production in Zambia: Twelve Biomasses Pelletized at Different Moisture Content2019In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, no 2, p. 2550-2575Article in journal (Refereed)
    Abstract [en]

    The use of charcoal and firewood for cooking is common in Zambia,and its utilization is suchthat the deforestation rate is high, energy utilization is low, and unfavorable cooking methods lead to high death rates due to indoor air pollution mainly from particulate matter and carbon monoxide.Byusing an alternative cooking method, such as pellet stoves, it is possible to offer a sustainable solution, provided that sustainable pelletproduction can be achieved. In this study, 12different available biomaterials were pelletizedina single pellet unitto investigate their availability as raw materials for pellet production in Zambia. The study showedthat sicklebush and pigeon pea generatedthe same pelleting properties correlated withcompression and frictionand that both materials showedlow moisture uptake. The study also identifiedtwo groups of materials that broadenedthe raw material base and helpedto achieve sustainable pellet production.Group 1consisted of materials with equal pelletingabilities (miombo, peanut shell, pigeon pea,and sicklebush) andGroup 2 consistedof materialsthat showed low impact of varying moisture content(eucalyptus, miombo, peanut shell, pigeon pea, and sicklebush). The hardest pellet was made from Tephrosia, which wasfollowed by Gliricidia.

  • 15.
    Karlsson, Simon
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Christiansson, Jonas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Calles, Olle
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Granö fiskavledare2015Report (Other academic)
    Abstract [sv]

    Utvinning av vattenkraft från Granö kraftstation påbörjades på slutet av 1950-talet. Ålen har sedan dess varit hindrad att passera genom kraftverket av ett finmaskigt och höglutande nät under ålens vandringssäsonger. Den alternativa vägen runt stationen har varit med spillvatten eller ner i den gamla ålkistan placerad i intagskanalen. Det är okänt hur många ålar som faktiskt vandrat ut med spillvattnet, men fångsterna i den gamla ålkistan har varit begränsade och mängder med ålar har dött på nätet. Ålen är nu akut hotad och åtgärder att mildra kraftverkens negativa inverkan på utvandrande blankål har högsta prioritet.

    Till följd av problem med igensättning av den så kallade ålspärren uppstod ett dammbrott 2010. För att öka dammsäkerheten och effektiviteten för åluppsamling designades och uppfördes en ny fiskavledare med åluppsamlingsanläggning 2011. Granö fiskavledare är unik i sitt slag då den har intagsgaller av kompositmaterial, ställbara lutningar (30-40˚), samt flyktöppningar som leder till en uppsamlingsbur. Vattnet från uppsamlingen pumpas tillbaka till intagskanalen, för att undvika onödigt spill.

    En stor del av utvärderingen bestod i märkning och spårning av blankål i anslutning till avledaren. Märkningsförsöken under 2012 och 2013 visade att endast en liten proportion av fisken hittar flyktöppningarna och kommer till uppsamlingsburen, dessutom har skador på fisken kunna relateras till avledaren och uppsamlingsburen. Totalt har 284 ålar märkts och 475 har visuellt bedömts för skador efter passage genom avledaren eller referensfisket Havbältan. Trots två dåliga ålvandringsår har majoriteten av den radiomärkta fisken ankommit till avledaren och totalt har 15 fisk återfångades. Hydrauliska mätningar i flyktöppningarna visar att vattenflödena igenom avledarsystemet är låga och andelen (vatten genom avledaren/totalflöde) är långt under rekommenderat vilket kan vara en anledning till de få återfångsterna av fisk.

  • 16.
    Kaukojärvi, Janne
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    The Role of Collaboration in Sustainable Innovation: A Case Study of a European R&D Consortium within the Area of Smart Paper-based Electronics2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    For the past decades, sustainability enhancement has become a necessity for ensuring a brighter future for the coming generations. Promoting technologybased innovation is seen as the main path for reaching the ambitious sustainable development goals. However, the academic literature about innovation highlights the need for an open innovation approach because sustainable innovations require consideration of complex issues throughout the entire product life cycle. Building on previous research on external collaboration and radical sustainability-oriented innovation, this qualitative single case study aims at extending the knowledge by particularly focusing on collaborative capabilities in the early development stages of publicly funded networks.

    The empirical findings were obtained through nine semi-structured interviews, and they were supported by available documentation, from the selected European research and development consortium within smart paper-based electronics. The outcome of the thesis is a framework summarizing success factors and challenges for the identified themes; capability, expectation, disposition, communication, management, commitment, and experience. Furthermore, the findings suggest that decision-making, preconditions, resourcing, and commitment, are the four main differences when comparing to collaborative capabilities in small and medium-sized enterprises, and large companies. Concerning managerial implications, top-level managers should carefully consider the strategic objectives of participating in networks, to guarantee organizational and personal commitment.

  • 17.
    Keck, Rolf-Erik
    Karlstad University, Division for Engineering Sciences, Physics and Mathematics.
    Strömningsmodell över Laxede kraftsstation2007Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
  • 18.
    Lundin, Lucas
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Karlsson, Simon
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Barriers and opportunities for implementation of a return system for industrial packaging: A case study at Valmet AB2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sustainability has become a more and more important aspect within companies worldwide. Environmental aspects within companies are often connected to higher profits and increased corporate image. One field of importance, to create a more effective supply chain within companies, regards to the logistic process. An area within logistics is reverse logistics, which regards to the activities related to taking back goods, information or material from the consumer or customer to receive value from it or to dispose it. By reusing goods or material, reverse logistics together with handling solutions could form a return system. Implementation of a return system could moreover be related to circular economy, which means effective use of resources within a closed loop supply chain. By combining logistics, handling, return system and circular economy, a more effective supply chain could be achieved.

    The study aims to create a theoretical framework on how barriers can hinder implementation of a return system and to identify potential solutions. This is done by investigating two research questions, namely how industrial packaging is handled today and further to investigate the barriers and opportunities for a return system. The questions and the aim will be answered through a case study of the company Valmet AB where internal documentation has been examined and interviews has been conducted. In addition to this, theory has been reviewed and a life-cycle assessment has been performed to examine possible benefits of a return system.

    The study shows that there exist barriers and opportunities, where some of them are mentioned in the existing theory while others are scarcely investigated. In the relevance to previous research, new barriers that need further investigation have been identified, in relation to the studied industry. These are lack of internal communication, lack of time and location barriers. Moreover, the study shows that there exists environmental incentive for implementation of a return system. However, it is hard to guarantee economic profit, since there are unknown costs due to storage, personnel and refurbishing. Future research should further examine the new barriers in the context of combined theoretical dimensions.

  • 19.
    Naqvi, Muhammad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013). Department of Energy, Building, and Environment, Mälardalen University, Sweden.
    Dahlquist, E.
    Department of Energy, Building, and Environment, Mälardalen University, Sweden.
    Yan, J.
    Department of Energy, Building, and Environment, Mälardalen University, Sweden & Department of Chemical Engineering, Royal Institute of Technology (KTH), Sweden.
    Naqvi, S. R.
    School of Chemical & Materials Engineering, NUST, Pakistan.
    Nizami, A. S.
    Center of Excellence in Environmental Studies, King Abdulaziz University, Saudi Arabia.
    Salman, C. A.
    Department of Energy, Building, and Environment, Mälardalen University, Sweden.
    Danish, M.
    State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, ECUST, China.
    Farooq, U.
    State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, ECUST, China.
    Rehan, M.
    Center of Excellence in Environmental Studies, King Abdulaziz University, Saudi Arabia.
    Khan, Z.
    Systems Power and Energy, School of Engineering, University of Glasgow, UK.
    Qureshi, A. S.
    Institute of Biotechnology and Genetic Engineering, University of Sindh, Pakistan.
    Polygeneration system integrated with small non-wood pulp mills for substitute natural gas production2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 224, p. 636-646Article in journal (Refereed)
    Abstract [en]

    This study aims to examine the potential substitute natural gas (SNG) production by integrating black liquor gasification (BLG) island with a small wheat straw-based non-wood pulp mills (NPM), which do not employ the black liquor recovery cycle. For such integration, it is important to first build knowledge on expected improvements in an overall integrated non-wood pulp mill energy system using the key performance indicators. O2-blown circulating fluidized bed (CFB) gasification with direct causticization is integrated with a reference small NPM to evaluate the overall performance. A detailed economic analysis is performed together with a sensitivity analysis based on variations in the rate of return due to varying biomass price, total capital investment, and natural gas prices. The quantitive results showed considerable SNG production but significantly reduced electricity production. There is a substantial CO2 abatement potential combining CO2 capture and CO2 mitigation from SNG use replacing compressed natural gas (CNG) or gasoline. The economic performance through sensitivity analysis reflects significant dependency on both substitute natural gas production and natural gas market price. Furthermore, the solutions to address the challenges and barriers for the successful commercial implementation of BLG based polygeneration system at small NPMs are discussed. The system performance and discussion on the real application of integrated system presented in this article form a vital literature source for future use by large number of small non-wood pulp industries.

  • 20.
    Nilsson, David
    Karlstad University, Faculty of Technology and Science.
    Energieffektiv utformning av luftaren airTURBO 1012006Independent thesis Basic level (professional degree), 15 points / 22,5 hpStudent thesis
    Abstract [en]

    Eden Aquatech has developed a surface aerator called airTURBO 101. Aerators are used to oxygenate water in basins and ponds within biological wastewater treatment. AirTURBO 101 consists of a submerged impeller that creates a vortex which transports air below the surface. The impeller is surrounded by a plastic cylinder. In the present design of the aerator, incoming water penetrates the cylinder through a circle of holes in the wall of the cylinder. This study has examined the original cylinder and an alternate design, where the cylinders where totally submerged and the water could pour over the brim. Two cylinders with submerged brim were tested. One had the same inlet area as the original cylinder and the other had a larger inlet area. These three cylinders has been tested and compared to find out which one has the highest oxygenation rate proportionately to the energy consumption.

    The following parameters were examined: the water motion inside the cylinders, energy consumption, the interface between air and water inside the cylinders and the oxygenation velocity. All experiments were carried out using scale models of airTURBO 101.

    Initial experiments showed that the vortices for all cylinders were more unstable than expected.

    The examinations of the water motion inside the cylinders showed that none of the designs could guarantee a continuous contact between the incoming water and the air.

    The energy consumption turned out to be similar for the different cylinders. The submerged cylinder with large inlet had slightly lower energy consumption than the other.

    The interface between water and air could not be calculated due to shortages in the specially developed mathematical formula. A visual depiction was not possible since the vortices were too unstable.

    When measuring the velocity of oxygenation the different cylinders had similar results at a constant power. When the power was doubled a considerable increase of velocity occurred. Also during these experiments the submerged cylinder with large inlet turned out to be slightly better than the other.

    One conclusion is that the submerged cylinder with large inlet is somewhat better than the other cylinders.

    Another conclusion is that the main part of the aeration does not occur in the interface between water and air in the vortex, but rather in the interface created by the impeller itself. Further development of this aerator should focus on the design of the impeller. The air bubbles created in the impeller should be as small as possible.

  • 21.
    Nordqvist, Sandra
    et al.
    Karlstad University, Faculty of Technology and Science.
    Öhman, Susanne
    Karlstad University, Faculty of Technology and Science.
    Vindkraft- En klass för sig2009Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
  • 22.
    Sandberg, Maria
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Studies to Avoid Decreased Efficiency in Multiple Stage Biological Wastewater Treatment Plants: Concerning Forests Industry Effluents2008Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The aim of this study is to prevent efficiency reduction in modern wastewater treatment plants for forest industry effluents. Biological processes are usually efficient in reducing biodegradable organic material. Since the technique depends on living microorganisms (MO) it is sensitive. Toxic substances can kill the population. It takes considerable time for the MOs to grow in number and the treatment efficiency will be affected accordingly. In a pulp and paper mill, a number of liquors are handled that can reach the treatment plant by accident. In this study the impact of black liquor spills on treatment efficiency has been studied.

    Biological treatment methods have been used for a long time. They have developed from general treatment plants to multiple stage concepts, where each stage is designed for its own purpose with specific MO cultures. In this thesis, a plant with the MultiBio concept, located at Gruvön Mill in Sweden has been studied. A laboratory scale MultiBio plant has been constructed for the trials in which efficiency during black liquor exposure has been measured. The measured laboratory results were evaluated by comparing them with simulated values and a mill case.

    When a shock of toxic black liquor passing through a MultiBio concept, the black liquor is diluted between the compartments. The first compartments that are exposed to high concentrations of black liquor are affected negatively. The MOs in the first compartment are fast growing and recover in a few days. The more sensitive activated sludge compartments are located further on in the plant. A toxic concentration is found in the activated sludge compartments only when the duration of the spill is 24 hours or more.

    Denying the MOs their needs can disturb biological treatments. Among many things, a biological process needs dissolved oxygen. Since aeration is energy consuming and expensive, there is a conflict between gaining high efficiency and, at the same time, decreasing the energy consumption. In this study, an approach to saving energy for aeration is initiated.

  • 23.
    Selöfalk, Sara
    Karlstad University, Faculty of Technology and Science.
    Avställning av luftad damm: Nedbrytning av organiskt material med hänsyn till årstidsvariation2006Independent thesis Basic level (professional degree), 10 points / 15 hpStudent thesis
    Abstract [en]

    As a result of increased permission to produce paper and paper pulp at the paper mill Gruvön AB in Grums the mill has built a multiple step waste water treatment construction. The previous treat construction was an aerated lagoon located in Vänern which now will be shut down. The aim of this report is to examine whether this aerated lagoon needs to be aereated to keep the decomposition of the organic material and/or to avoid origin of odours.

    The decomposition rate is studied by loss on ignition, COD-tests and alcalinity. The COD-tests was performed in the environmental lab at Gruvön by the ampoule method according to Hach-Lange. The alcalinity was determined by titration with sulfuric acid.

    The experiments were performed during a period of three months. Sludge was collected from three test points from the lagoon. The sludge was then separated into one construction to measure the aerobic decomposition and one to measure the anaerobic decomposition. The results show that the decomposition rate is low. The decomposition rate has been evaluated by linear regression. This method indicates that it would take about three years for the anaerobic process and about 15 years for the aerobic process to degrade all the organic compound. The difference in time between the two processes is probably dependent on for example the test points localization in the lagoon.

    To turn off the aerators of the lagoon could save energy and gain economical profits. The anaerobic decomposition that begins after closing down the aerators could result in creation of chemical odours such as hydrogen sulphide and methane.

  • 24.
    Skantz, Christoffer
    Karlstad University, Faculty of Technology and Science.
    Äldreboendet på Zakrisdal: En studie om solvärme med säsongslagring2008Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A home for elderly is planed to be built at Zakrisdal, Karlstad, Sweden. The heat source for the building was at the time not determined. In order by the local government of Karlstad this report is meant to examine if the need of heat could be provided only by solar heat combined with a seasonal heat storage. The problem to solve is, if the need of heat from the home for elderly is provided from only solar heat, whitch dimensions of the solar collectors and the storage is needed?

  • 25.
    Skogsdal, Rickard
    Karlstad University, Faculty of Technology and Science.
    Evaluation of treatment techniques of the effluent air at biogas upgrading plants2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In nature, organic matter is degraded by microorganisms. During the degradation gases formedincludes methane, carbon dioxide, hydrogen sulfide, and small amounts of other gases such asVOCs. This has been utilized with help of anaerobic digesters, where environments have beencreated, in which these organisms thrive. In these chambers the gases are collected together intosomething called biogas.Biogas is a renewable energy source where the methane gas natural affinity for combustion inoxygen-containing environments is being used. By separating the methane from the other gases, theenergy value becomes closer to that of natural gas. The upgraded biogas can thus act as a substitutefor natural gas and be used as a fuel for vehicles, a need that has increased during the last years.This is preferred since natural gas is a fossil fuel.A technique used for upgrading biogas is water scrubbers. By using the gases different tendency todissolve into the water, carbon dioxide and hydrogen sulfide can be removed. During this process asmall amount methane and VOC becomes absorbed as well. The upgraded biogas obtains a methanecontent of approximately 98 % and can then be used as a fuel for vehicles. The removed gases are atthe same time released from the water to the effluent air leaving the upgrading plant. This has beendeemed inappropriate since the hydrogen sulfide is a corrosive and highly toxic gas. The methaneand VOCs that leaves with the effluent air provides negative effects to the greenhouse effect andglobal environment.This study has examined the issue of how to treat the gases that are emitted by the effluent air.Using measurements to find the percentage amounts of the different gases in the effluent air and inthe raw biogas, annual quantities of emissions could be calculated. From these, various treatmentmethods have been analyzed where the author finally concluded that a reduction of hydrogensulfide should be achieved with help of iron in a filter. Methane has instead been proposed to betreated with a compost filter.

  • 26.
    Sohlberg, Thomas
    Karlstad University, Faculty of Technology and Science.
    Biologisk reducering av nitrat och nitrit i vatten2007Independent thesis Basic level (professional degree), 15 points / 22,5 hpStudent thesis
    Abstract [en]

    During the summer 2007 was a scrubber tested at Gruvön papper mill in Grums. The scrubber reduced NOx with 90 % in flue gas. NOx was transferred from the flue gas to a scrubber liquid as nitrate and nitrite. The scrubber liquid needs to be purified from nitrate and nitrite.

     

    One possible solution is to clean the scrubber liquid in Gruvön biologic cleaning construction.

    Microorganisms in the biologic cleaning construction need to assimilate nitrogen. There are environments free from oxygen in the cleaning construction. Microorganisms can reduce nitrate in environments free from oxygen.   

     

    At the implementation was a labmodel built of the two first steps from Gruvön papper mill. Wastewater was collected from Gruvön papper mill. The wastewater was dosed with salts of nitrate and nitrite and pumped into the labmodel.

    The results showed that nitrate and nitrite can be reduced in content with help of the biological cleaning construction.

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