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  • 1.
    Andersson, Linn
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Evaluation of biosand filter as a water treatment method in Ghana: An experimental study under local conditions in Ghana2017Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The availability to clean drinking water is something a lot of people take for granted today. Daily, there are about 1.8 billion people around the world that drinks water from a contaminated water source. Unfortunately, the deficiency is a fact, and about 361 000 children under the age of five die each year because of diarrheal disease (WHO, 2016a). 

    Earlier studies show that a biosand filter is an easy and efficient water purification method that cleans the water both physically, biologically and chemically. A biosand filter is often built using local material and is filled with sand, which makes the construction cheap and easy to repair is needed. Earlier studies have shown that this purification method can reduce waterborne disease by 99,9% with the help of a biofilm layer which develop in the top layer of the sand if the conditions are meet (CAWST, 2009).

    The purpose with this study was to build and evaluate a biosand filter as a water treatment method in Ghana. In total, three biosand filters was built with local material, each with different sand heights. The evaluation was done by studying the waters physical, biological and chemical properties before and after the filtration, which then was compared to the water quality standards from the World Health Organization (WHO) and Sweden. The results show that none of the three filters could produce water which met the standards for drinking water, which might be caused by the high flow of water through the filter which prevented the biofilm to grow. With the help from the results in Ghana, a new design of a water filter has been made to reduce the flow of water through the filter. Which gave a new biosand filter design with a diameter of 42 cm that, sand height of 80 cm and gravel height of 15 cm.  

  • 2.
    Arvidsson, Daniel
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Estimation of the possible waste reduction by the implementation of SODIS: A numerical-, experimental- and social study executed in Ghana2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Lack of safe drinking water is one of the biggest humanitarian problems in the world today. Over one billion people in developing countries have no access to good quality drinking water, and subsequently, diarrhoea caused by unclean water leads to 1.8 million deaths of children under the age of five. That corresponds to 90 per cent of all deaths among children in that age group. However, by improving water and sanitation management, one tenth of all worldwide cases of disease can be prevented. In relation to this, the United Nations has launched the seventh millennium goal, which is to half the proportion of people lacking access to safe drinking water by year 2015 (compared with the proportion of year 2000). Therefore, it is important to both improve and develop water treatment techniques in order to achieve a sustainable development, especially in the third world.

     

    Kofi Ansah and Edumafa are two villages on the Ghanaian countryside. Here, as in the rest of Ghana, it is common to drink water from throwaway plastic containers. This is because the water quality is poor in the stationary water sources such as tanks and wells etc. The plastic containers contribute to a big waste problem and it´s therefore desirable to improve the water quality in stationary water sources in order to reduce the waste problem that now is occurring.

     

    Solar Disinfection, or SODIS, is a water treatment technique that is based on solar radiation. Water containers (usually PET bottles) are filled with water and then exposed to the sun for about six hours. The germicidal effect can be derived to thermal heating in combination with the sun’s ultraviolet radiation. The technique is suitable in the third world since the treatment procedure is both simple and inexpensive. The purpose of this study was to estimate the possible waste reduction regarding the small plastic containers by the implementation of SODIS as a water treatment technique, and evaluate if SODIS is an adequate way to improve the quality of water collected from stationary water distribution systems in Ghana.

     

    The study has shown that SODIS is an adequate method for producing low health risk water at a household level in Ghana. A solar exposure of six hours is enough to reach a safe bacterial content within the treated water. It is also clear that SODIS could reduce the present waste problem regarding the throwaway plastic containers by more than 1600 plastic bags per person and year, and that the Ghanaians attitude to start performing SODIS is positive.

     

    Further work should be aimed at implementing SODIS as a water treatment technique by teaching the Ghanaian people, especially in the rural areas, the importance of water and sanitation issues. The implementation of SODIS is a long term project that cannot be accomplished singlehandedly. It can be achieved by instructing certain people in the villages as to how the procedure is done. For this to be effective, these individuals should preferably be well educated and speak both English and the local language. These people can in turn educate and instruct the other villagers in how SODIS is executed and by doing so complete and secure a sustainable use of the technique.

  • 3.
    Bourne, D.
    et al.
    Univ Glasgow, Sch Math & Stat, Glasgow.
    Fatima, T.
    Eindhoven Univ Technol, Dept Math & Comp Sci, NL.
    van Meurs, P.
    Eindhoven Univ Technol, Dept Math & Comp Sci, NL.
    Muntean, Adrian
    Eindhoven University of Technology,.
    Is adding charcoal to soil a good method for CO2 sequestration? -: Modeling a spatially homogeneous soil2014In: Applied Mathematical Modelling, ISSN 0307-904X, E-ISSN 1872-8480, Vol. 38, no 9-10, p. 2463-2475Article in journal (Refereed)
    Abstract [en]

    Carbon sequestration is the process of capture and long-term storage of atmospheric carbon dioxide (CO2) with the aim to avoid dangerous climate change. In this paper, we propose a simple mathematical model (a coupled system of nonlinear ODEs) to capture some of the dynamical effects produced by adding charcoal to fertile soils. The main goal is to understand to which extent charcoal is able to lock up carbon in soils. Our results are preliminary in the sense that we do not solve the CO2 sequestration problem. Instead, we do set up a flexible modeling framework in which the interaction between charcoal and soil can be tackled by means of mathematical tools.We show that our model is well-posed and has interesting large-time behaviour. Depending on the reference parameter range (e.g., type of soil) and chosen time scale, numerical simulations suggest that adding charcoal typically postpones the release of CO2. © 2013 Elsevier Inc.

  • 4.
    Fokkema, Maaike
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013).
    Spårämnestillsatsers påverkan på biogasproduktionen vid anaerob rötning av avloppsslam: Behovet av spårämnen vid slamrötning på Karlstads reningsverk2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Swedish government has set a national goal to have no vehicles running on fossil fuels in year 2030. One of the fuels that can replace the fossil fuels of today is biogas. The biggest wastewater treatment plant in Karlstad, called Sjöstadsverket, is already producing biogas and is expanding to receive more sludge in the future. Because of this, Sjöstadsverket wants to investigate the possibility of a more effective biogas production. A common way to improve biogas production is trace element additives. Therefor the addition of cobalt, nickel, iron and magnesium has been investigated through small scale thermophilic anaerobic digestion trials in batch reactors. The trace elements have also been added in combination with EDTA to investigate the bioavailability of the trace elements. In addition to these experiments a correlation analysis was performed where different factors that might influence the biogas production were investigated for year 2017.

    The results from the digestion trials prove that no addition of iron, magnesium, cobalt or nickel will increase the biogas production. Instead, the biogas production was inhibited during two out of three experiments. These results indicate that the organisms in the digester at Sjöstadsverket already have a sufficient amount of trace elements. The addition of EDTA did not increase the biogas production either which indicates that the trace elements also are bioavailable to a sufficient extent. The results from the digestion trials are validated by the correlation analysis because no correlation could be found between the biogas production and the investigated trace elements.

    The results from the correlation analysis show that the pH-level affects the biogas production negatively. The results indicate that the pH-level is to high, something that was also observed during the digestion trials. A higher flow rate into the digesters could lower the pH-levels according to further correlation studies. This has also been observed during the digestion trials where a shorter retention time lowered the pH-levels. Because Sjöstadsverket bases their retention time on a stable volume in the digesters, it could be possible for them to increase the biogas production by increasing the flow rates, which will happen when they start receiving more sludge. Because these conclusions are mainly based on correlations, further studies of the influence of pH-levels and retention times on the biogas production at Sjöstadsverket are recommended.

  • 5.
    Granbom, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Nitritomvandling vid Skebäck avloppsreningsverk2016Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    On several occasions fish died in Hjälmaren due to, among other things, elevated nitrite levels in the lake. A contributing factor turned out to be the high nitrite content that leaves the wastewater treatment plant Skebäck, located in Örebro. The wastewater is purified from nitrogen through nitrification and denitrification where nitrite occurs as an intermediate in several reaction steps. The report contains theory round the formation of nitrite and the results from samplings where nitrite concentration was determined. The objective was to increase nitrite conversion and thereby decrease the content of nitrite in the effluent water, by studying the increase of nitrite.   Samplings started in March and no changes in the process where made, the first samples were analyzed to determine where the nitrite accumulation occurred. The samplings were taken in the intermittently aerated basin, wish includes a aerated period and a nonaerated period.   The initial samples showed that nitrite accumulates when there is oxygen in the basin. The content of nitrite decreases when there is no oxygen in the water. The ammonium limits were changed in one basin because it was suspected that the bacteria were becoming stressed by the intermittent aerated start-stop process. This resulted in a longer aerated period for the nitrified bacteria to grow and due to the change it was expected that the bacteria would thrive. This proved insufficient for nitrite oxidation to take place, but the concentration of nitrite at this time was at least lower.  These changes did not show any reduction in the nitrite concentration. Suggestions for future work are addition of an extern carbon source and optimizing the aeration. 

  • 6.
    Granström, Karin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Regler för hantering av rötrest2014Report (Other academic)
    Abstract [sv]

    Innehållsförteckning

    INLEDNING

    PROBLEM MED ATT TA TILLVARA RÖTREST

    Tungmetaller

    Smitta

    REGLERING AV ANVÄNDANDET AV RÖTREST SOM GÖDNING

    Certifiering av biogödsel

    Hygieniseringskrav för biogödsel

    Certifiering av rötslam

    Hygieniseringskrav för rötslam

    ACCEPTANS?

    MÖJLIGHETER OCH RISKER MED SAMRÖTNING

    REFERENSER

  • 7.
    Granström, Karin
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Resource recovery from pulp and paper mills by adaptation of their wastewater treatment to biogas production2014In: 19th European Biosolids & Organic Resources Conference and Exhibition, Manchester, UK, 17-19 November 2014., 2014Conference paper (Other academic)
  • 8.
    Granström, Karin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Larsson, Amanda
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Biogas from algae farmed in pulp and paper mill wastewater2015In: GGROS 2015, Örnsköldsvik, Sweden, 23-25 March 2015., 2015Conference paper (Refereed)
    Abstract [en]

    Pulp and paper mills have waste streams that can be used for the farming of algae. The mills wastewater treatment provides heat to the algae ponds and the flue gas provides carbon dioxide. A current project is aiming at producing oil, for biodiesel or lubricating oil, from mill-farmed algae. Ten pools have been constructed and seeded with different strains of algae. After harvest and separation of oil, there is a leftover algae pulp. The fate of this algae remnant is an important part in achieving economic and energy viability for the whole process.

    The purpose of this work was to study the potential to produce biogas from algae grown in pulp and paper mill wastewaters, for different algae strains and pond conditions, with differing degrees of oil separation before the anaerobic digestion stage. The methane potential of the various algae pulps was tested by anaerobic digestion batch assays under thermophilic conditions for 23 days. 

    Pre-treatment of substrate is sometimes done in order to reduce the necessary retention time of biogas production. One batch of algae was subjected to either thermal pre-treatment or NaOH or comminution, to assess the effect on these methods on methane production.

    Ammonia concentration and pH in the digestate was analyzed to monitor the anaerobic digestion process, and the algae pulp’s content of fat, protein and carbohydrates were analyzed to characterize the substrate. In addition, the dewaterability of algae and of algae digestate was examined, as the dewaterability affects transport costs and possible use of the digestate.

    During the first year of operation, the algae in the range pond produced 186 ml CH4/g VS. The pre-treatments did not significantly affect the methane potential. The second year of operation saw more adapted strains of algae which are expected to produce somewhat different results [data from these experiments can be presented at the conference].  

    The research is of importance for the development of the biogas market as new substrates are needed to reach the volumes that are necessary to achieve economic viability for biogas plants. By characterizing the algae, it should be easier to see which role they are suitable to play in a co-digestion mix. Furthermore, the production of bio-oil and biogas together benefit the bioenergy system as a whole.

  • 9.
    Granström, Karin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Montelius, Josefine
    Pre-Treatment To Enhance Biogas Yield from Pulp and Paper Mill Sludge2014In: Journal of Chemistry and Chemical Engineering, ISSN 1934-7375, E-ISSN 1934-7383, no 8, p. 825-833Article in journal (Refereed)
    Abstract [en]

    The purpose of this work was to study the potential to enhance biogas production from pulp and paper mill sludge by the use of thermal pre-treatment in combination with chemical pre-treatment. Biogas from waste is a renewable fuel with very low emissions during combustion. To further reduce the use of fossil fuels, more biogas substrates are necessary. Pulp and paper mill sludge is a large untapped reservoir of potential biogas. Pulp and paper mill sludge was collected from a mill that produces both pulp and paper and has a modified waste activated sludge system as part of its wastewater treatment. Pre-treatments were chosen heat (70 oC or 140 oC) combined with either acid (pH 2 or pH 4) or base (pH 9 or pH 11, obtained with Ca(OH)2 or NaOH). Biogas potential was tested by anaerobic digestion batch assays under mesophilic conditions. All pre-treatments were tested in six replicates. Biogas volume was measured with a gas-tight syringe and methane concentration was measured with a gas chromatograph. The methane yield from sludge subjected to thermal pre-treatment at 70 oC did not differ from the untreated sludge, but thermal pre-treatment at 140 oC had a positive effect. Within the 70 oC thermal pre-treatment group, the pH 2 acid was the most successful chemical pre-treatment, and Ca(OH)2 pH 9 had the least effect with no measurable improvement in methane yield. For the 140 oC thermal pre-treatment group, acid and NaOH impacted methane production negatively, while the Ca(OH)2-treated sludge did not differ from sludge with no chemical pre-treatment. In conclusion, thermal pre-treatment at 70 oC showed no effect, whereas, pre-treatment at 140 oC improved methane yield with 170%, and for this sludge additional, chemical pre-treatments are unnecessary.

  • 10.
    Granström, Karin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Montelius, Josefine
    Pre-treatment to enhance biogas yield from pulp and paper mill sludge2014In: 2nd International conference on environmental science and technology ICOEST’2014, Side, Turkey, 14–17 May, 2014., 2014Conference paper (Refereed)
  • 11.
    Granström, Karin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Samson-Akpan, Enobong
    Hagelqvist, Alina
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Sustainable energy from pulp and paper mill sludge by co-digestion with municipal sludge under thermophilic conditions2014In: World bioenergy 2014, Jönköping, Sweden, 3-5 June 2014., 2014Conference paper (Other academic)
  • 12.
    Graversgaard, Morten
    et al.
    Aarhus University, Denmark.
    Hedelin, Beatrice
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013). Karlstad University, Faculty of Social and Life Sciences, Centre for Climate and Safety.
    Smith, Laurence
    SOAS University of London, UK.
    Gertz, Flemming
    SEGES, Landbrug & Fødevarer F.M.B.A., Denmark.
    Højberg, Anker Lajer
    Geological Survey of Denmark and Greenland (GEUS), Denmark.
    Langford, John
    University of Melbourne, Australia.
    Martinez, Grit
    Ecologic Institute, Germany.
    Mostert, Erik
    Delft University of Technology, The Netherlands.
    Ptak, Emilia
    Aarhus University, Denmark.
    Peterson, Heidi
    University of Minnesota, MN, USA; International Plant Nutrition Institute, MN, USA.
    Stelljes, Nico
    Ecologic Institute, Germany.
    van den Brink, Cors
    Royal Haskoning DHV, The Netherlands; Groningen University, The Netherlands.
    Refsgaard, Jens Christian
    Geological Survey of Denmark and Greenland (GEUS), Denmark.
    Opportunities and barriers for water co-governance: A critical analysis of seven cases of diffuse water pollution from agriculture in Europe, Australia and North America2018In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 10, no 5, article id 1634Article in journal (Refereed)
    Abstract [en]

    Diffuse Water Pollution from Agriculture (DWPA) and its governance has received increased attention as a policy concern across the globe. Mitigation of DWPA is a complex problem that requires a mix of policy instruments and a multi-agency, broad societal response. In this paper, opportunities and barriers for developing co-governance, defined as collaborative societal involvement in the functions of government, and its suitability for mitigation of DWPA are reviewed using seven case studies in Europe (Poland, Denmark, Sweden, The Netherlands and UK), Australia (Murray-Darling Basin) and North America (State of Minnesota). An analytical framework for assessing opportunities and barriers of co-governance was developed and applied in this review. Results indicated that five key issues constitute both opportunities and barriers, and include: (i) pressure for change; (ii) connected governance structures and allocation of resources and funding; (iii) leadership and establishment of partnerships through capacity building; (iv) use and co-production of knowledge; and (v) time commitment to develop water co-governance

  • 13.
    Sandberg, Maria
    Karlstad University, Faculty of Technology and Science.
    Efficient treatment of forest industrial wastewaters: Energy efficiency and resilience during disturbances2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This work concerns the efficient treatment of wastewaters from pulp and paper mills by means of aerobic biological processes. For treatment processes there are many aspects of efficiency and the present study investigates both energy efficiency and purification efficiency during disturbances.

    Special focus is put on wood extractives, such as resin acids and fatty acids, since they can cause negative effects in fish and other organisms in the receiving waters. They can furthermore be toxic to microorganisms in a biological treatment plant. They also affect oxygen transfer, which is important for energy efficient aeration of aerobic biological treatment processes.

    This thesis includes five papers/studies and presents a strategy for efficient treatment of forest industrial wastewaters. The results should help creating resilient wastewater treatment strategies with efficient use of energy. One new strategy proposed here includes separation of extractives before the wastewater is treated biologically, and the use of the extra amount of sludge as an energy source, shifting the energy balance from negative to positive.

  • 14.
    Sandberg, Maria
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Rixen, Alexandra
    Chemical flocculation as pretreatment for energy efficient biological treatment2012In: 10th IWA Symposium on Forest Industry Wastewater and 8th International Conference on the fate and effect of Pulp and Paper Mill Effluents, 2012, p. 42-Conference paper (Refereed)
    Abstract [en]

    Biological treatment of forest industry wastewaters uses large amounts of electrical energy. For many mills aeration is the single most energy intensive process in the wastewater treatment plant. The oxygen transfer from bubbles into the water volume is quite slow with low aeration efficiency as result. If the oxygen transfer can be improved, the efficiency can be improved and less compressed air will be needed for aeration with decreased energy costs as the result. It has been shown that surface-active extractives, such as fatty acids and resin acids, have a large impact on oxygen transfer in diffuser aeration systems. With chemical flocculation, extractives can be removed from the process streams. Trials have been made where pulp-mill process streams were pretreated with chemical flocculation before the oxygen transfer tests. When the chemical flocculation conditions were optimized to increase surface tension in the process stream, extractives were removed and the oxygen transfer rate increased in the following oxygen transfer tests. With the pretreatment also COD concentration decreased. The effect will be less need for oxygen for degradation in the following biological process. With decreased COD concentration and increased oxygen-transfer rate, energy can be saved in the biological treatment. Energy savings resulted in greater economic return than the cost for flocculating chemicals. If waste sludge can be used as energy source, one can even achieve a better result.

    Acknowledgements. This work was supported by ÅF-forskningsstiftelse and Stora Enso Skoghall mill.

  • 15.
    Ståhl, Magnus
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Minska energianvändningen i pelletspressen och öka pelletskvaliteten2013Conference paper (Other academic)
    Abstract [en]

    The wood fuel pellet industry demands energy efficient solutions for their production since these not only save energy but also money. One way of achieving this is to use additives. Choosing the right additive can save money but also increase the quality of the pellets, a win win situation. In this work, it is investigated how different kind of additives affect the energy use of the pelletizing equipment and also how it affects the durability of pellets. The best results were achieved using oxidized cornstarch as an additive during pellet production, it not only decreases the energy used the most but also produce the pellets with highest durability.

  • 16.
    Svanberg, Erik
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Lakvattenhantering och kväverening vid Östby deponi2013Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
  • 17.
    Svensson, Fredrik
    Karlstad University, Faculty of Technology and Science.
    Energianalys av vattenburna och luftburna klimatsystem i ett kontor: Utnyttjande av frikyla oc nattkyla2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 18.
    Trosgård, Emma
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Small-scale biogas production in the province of Pampanga, Philippines2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study was to contribute to sustainable development in the Pampanga province, Philippines. The Philippines are facing several major environmental problems; pig production represents a major contributing factor to pollution and eutrophication of water bodies in the country. At present there is no requirement for purification of wastewater from backyard (small-scale) farms. With the help of anaerobic digestion the manure could be used to produce biogas.

    The study’s objective was to determine an anaerobic digester design and substrate composition for small-scale biogas production in backyard farms (20 pigs). To achieve this objective, several goals were defined; (1) determine the best substrate composition for biogas production, through the use of lab experiments, (2) determine a design best suited for small-scale use, (3) test the substrate and design in-field, (4) determine the impact of different inoculum, (5) determine a small-scale design based on local conditions such as finance, building materials, climate etc., (6) evaluate the digestates’ properties as a bio-fertilizer and (7) compare the biogas production with an existing biogas plant in Pampanga. Four combinations of food waste and pig manure were tested at Karlstad University’s biogas lab. The best composition had VS-ratio 1:2 for pig manure to food waste, and produced 111.1 NmL CH4/g VSadded. The chosen design was a floating drum digester. It was tested together with the substrate and two inoculums (cow manure and digestate from an existing biogas plant) in four pilot plants during 32 days. The plants showed symptoms of inhibition in biogas production and the pH dropped to toxic levels (below pH 6).

    At the end of the study, the plants had similar cumulative biogas production. The mean production was 1764 NmL and the average methane content was 33.6%. The plants with inoculum from an existing biogas plant showed signs of recovering from the low pH. The plants with cow manure as inoculum showed increasing signs of inhibition. The mean phosphorus content of the digestate was 1.3% TS and nitrogen content was 6% TS. The carbon to nitrogen ratio was on average 8:1, which had a positive impact on nitrogen mineralization in the soil (if used as bio-fertilizer). The digestate had high levels of VFA, which reflected improper substrate composition. The large fraction of food waste was the likely cause of inhibition; easily digestible carbohydrates lead to the pH drop and high levels of VFA.

    Based on the field study and literature, another substrate composition was recommended for the final design. The suggested substrate had VS-ratio 2:1 for pig manure to food waste. A variant of the floating drum digester was recommended, where several digesters could be connected in series and the number of digesters could be adapted to the number of pigs. The digester volume was 6.2 m3; the expected biogas production was 2.6 m3 with 70% methane content. This facility would result in a digestate containing 0.2 kg phosphorus and 0.7 kg nitrogen per day. Comparisons between the existing plants’ biogas production and the pilot plants could not be done due to the fact that the plant lacked methods for measuring their biogas production and methane content. However, the study’s overall findings make a strong argument for the use of biogas in backyard farms, for mitigating many of the Philippines’ water quality issues arising from pig production. 

  • 19.
    Wieslander Jansson, Axel
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    En studie i vattenrening med elektrokoagulation: Koaguleringsförmågan hos utvalda föreningar2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Water- and energy consumption is one of humanities biggest current and future problems because of ever increasing global water consumption and because of better living conditions, increasing population and industrialization. Polluted water results in diseases, reduced life expectancy, sanitation and reduced overall health of those affected. Purifying water in an energy and environmentally effective way is therefore a must for a sustainable future.

    A study of the coagulation capabilities for a select number of organic compounds by electrocoagulation has been performed at Axolot Solutions AB. Axolot Solutions AB is a company developing electrochemical water treatment solutions, with a focus on the electrocoagulation process. The compounds that have been studied are sugars (raffinose, maltose, glucose, lactose), organic acids (formic acid, citric acid, hexanoic acid, butyric acid, octanoic acid), alcohols (1-propanol, 2-propanol), fatty acids (lecithin), others (formaldehyde, vanillin, nonylphenol, α-pinene). Industrial water coming from a debarking process was also investigated as well as two compounds that are often present in this type of water, xylan and lignin.

    The treatment efficiency was determined by measuring the COD values of the investigated water before and after the electrocoagulationprocess. Each compound was studied by using an iron anode and an aluminum anode at four different initial pH values: 4, 6, 7.5, 9. Different current densities were also studied for some of the investigated compounds.

    The results show no COD reduction for sugars, alcohols, organic acids and xylan. The process resulted in large reductions of the compounds lecithin (85.5%) and lignin (98.1%). A lesser reduction was found for the waters containing: nonylphenol (33.6%), α-pinene (42.1%) and barkwater (21.5%). A reduction of COD was also found in the water containing vanillin with an initial pH of 4 that was treated with an aluminum anode was affected. The most efficient setup for the investigated compounds varies. For that reason, no conclusion as to which initial pH and anode that should be for electrocoagulation processes in general can be drawn.

  • 20.
    Wikström, Fredrik
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Williams, Helén
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Packaging and Food Waste Behavior2017In: Reference Module in Food Sciences, Elsevier, 2017, p. 1-4Chapter in book (Refereed)
    Abstract [en]

    Packaging saves food by protecting the content from physical and chemical degradation during the distribution and storage processes. However, packaging can do much more than that. This article explores how the design of a package may help, or indeed hinder, the consumer to avoid wasting food. A number of packaging attributes influence consumer behavior. The influence is different depending on the product‘s characteristics and the needs of the consumer. For many products, it might be better to add packaging material, for example, by creating smaller sizes of the product to reduce food waste and the overall environmental impact.

  • 21.
    Öberg, Emilia
    Karlstad University.
    Ammoniumkvävereduktion vid lakvattenrening med mobil bioreaktor: vid olika temperaturer och fosfortillskott2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The need for energy efficient and well-functioning water treatment systems is high, and grows as the growing population increases. Leachate is formed as water flows through landfilled waste. The problem of leachate treatment is that the reactors are located outdoors, which causes low temperatures during the winter months. As the leachate treatment is mainly carried out with biological purification techniques, the low temperatures cause a decrease in bacterial activity, which reduces the purification efficiency. Another problem that often arises in this type of water treatment is that the contaminated water consists of high nitrogen levels, while phosphorus levels are low. This gives an imbalance in the metabolism of the bacteria and can lead to limitations in purification efficiency. In this work, a newly developed bioreactor, which is tested at Djupdalen's waste facility, has been investigated. The bioreactor was put into operation in autumn 2015 and from April to December 2016. Measurement data from Djupdalen based on monthly water samples and chemical analyzes for 2014-2016 have been studied to find out the bioreactor's contribution to the purification efficiency of ammonium nitrogen. Water sampling was carried out in May 2017, where purification efficiency and active biofilm surface were calculated during the operation start of the bioreactor. Finally, experiments were performed where biofilms from Djupdalen were tested at 17-18 as well as 12-15 ° C with different levels of phosphorus supplementation, to investigate whether purification efficiency could be improved if phosphorus levels were increased. The results indicate that the bioreactor contributes to a significant improvement in the purification efficiency of the aeration reactor, but there is still an improvement potential. Several of the environmental factors in the aeration reactor cause less favorable conditions for bacterial growth, such as temperatures below 15 ˚C, severe phosphorus deficiency in the incoming leachate and slightly for basic pH values. Through water sampling and the accompanying chemical analysis it was found that temperatures above 15 ˚C in the leachate favor a faster development of the biofilm. Finally, laboratory experiments showed that phosphorus additions at temperatures of 12-15 ° C resulted in increased purification efficiency, while the result was unchanged for temperatures of 17-18 ° C at a water residence time at 24 hours. However, at a lower water residence time of 16 hours, the phosphorous supplement gave an effect for both temperatures. This indicates that a phosphorus supplement during the autumn of the aeration reactor, when the temperatures in the leachate go below 15 ˚C, should allow the bioreactor to improve its purification efficiency despite the sinking water temperature.

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