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  • 1.
    Abdulrazaq, Erol
    et al.
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Henrik, Persson
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Syresättning av avloppsvatten: En undersökning av luftningsmetoder på reningsverk2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This essay has been done at the request of Marinfloc AB. It consists of various measurements and experiments investigating the sewage water treatment on a number of different plants. The measurements were executed in the part of the plants called secondary treatment. The objective with secondary treatment is to let micro-organisms remove dissolved and suspended biological and organic matter. The factors which were investigated were which methods are used to oxygenate the sewage water, what level of oxygen saturation is obtained with each method and the power consumption required oxygenating the sewage water. An experiment was carried out on Marinflocs’ own sewage treatment plant with the objective to determine if there is any time difference in oxygenating pure water versus unprocessed sewage water. The conclusion reached was that the four land-based sewage treatment plants that were investigated oxygenate by the same principle. The oxygenation is done by aeration from the bottom in respective aeration tank. The level of oxygen saturation was between 1, 8 – 5, 9 mg oxygen per liter sewage water in all plants. Marinflocs’ current sewage treatment plant uses another principle to oxygenate and its oxygen saturation was measured to a level of 12 mg/l. The experiment on Marinflocs’ own sewage treatment plant concluded that there is a time difference in oxygenating pure water versus unprocessed sewage water. The pure water gets oxygenated faster. 

  • 2.
    Alessandro, Martini
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology.
    Biosensorsystem för övervakning av vattenkvalitet2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sweden's drinking water quality is considered to be high partly due to a high quality of the raw water and a well developed sewage infrastructure. Despite this, there is water contamination that could be prevented by installation of a sophisticated early warning system. Some of the major players in the production of drinking water have already invested in different types of early warning systems to ensure drinking water of high quality. There are various forms of early warning systems where automatic monitoring of E. Coli is an interesting alternative. Today's technology allows for this type of measurement, but it is often expensive and sometimes slow.

    This work aims to investigate whether the phenomenon of Extraordinary Optical Transmission (EOT) can be used as the technology of sensors for real-time measurement of indicators of fecal contaminated water. EOT is a transmissions peak which arises due to plasmon resonance. The study was conducted by performing verification measurements by spectrophotometry to detect the EOT. After this biomeasurements where done to show that the surface of the sample can be functionalized to provide the opportunity to choose which analytes should be detected.

    The verifying measurements showed that EOT was detected for one of the five samples where the hole size was 400 nm and the hole spacing was 600 nm. This is due to the high signal strength and to the fact that the phenomenon occurred within the measurement range of the instruments. Samples where designated with the name sPa where s indicates hole size in nm and a hole spacing in nm. The signal strength of the sample 140P600 and 200P600 was too low to determine whether EOT occurred. For samples 400P1000 and 600P1000 calculations showed that EOT occurred outside the measurement range, which meant that EOT could not be measured. Sample 400P600 was chosen to implement bio-measurements wherein the surface was functionalized with biotin Bovine serum albumin (B-BSA) to later bind with fluidMAG Streptavidin. Both B-BSA and streptavidin was bound as shown by the kinetic measurements. 

  • 3.
    Ambjörnsson, Linn
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Ewald, Katti
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Johansson Kling, Erika
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Larsson, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Marie, Selenius
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Elin, Svedberg
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Purification of arsenic contaminated water using ferrihydrite with consideration to current circumstances in Burkina Faso2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Ferrihydrite in a suspension has been studied as a solution for purification of arsenic contaminated water. Many development countries, amongst them Burkina Faso, have arsenic in their groundwater and the current methods for purification are too expensive. Measurements have shown extremely high levels of arsenic in the groundwater in several places in Burkina Faso. Since the availability of surface water is limited, the groundwater is still used as drinking water.

     

    A suspension of ferrihydrite has capacity to adsorb arsenic in water due to its chemical characteristics. Small-scale laboratory work with ferrihydrite suspensions has been performed in parallel in Uppsala, Sweden, and Ouagadougou, Burkina Faso. To purify the water with regard to the economical and practical circumstances in Burkina Faso, a column with safety filter was made out of simple materials such as plastic bottles, plastic tubes and glass wool. The contaminated water was flowing upwards through the column to prevent the filter from clogging.

     

    In Uppsala it was discovered that a 1 L ferrihydrite suspension containing 10 g ferrihydrite can adsorb 0.7 g arsenic while it was shaken and centrifuged well. In Ouagadougou it was possible, in the setup, to clean 2 L arsenic contaminated water with the concentration of 100 µg/L. The conclusions from the experiments in this project are that ferrihydrite can adsorb arsenic in contaminated water but that the setup used needs to be further evaluated and developed

  • 4.
    Anbalagan, Anbarasan
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Indigenous microalgae-activated sludge cultivation system for wastewater treatment2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The municipal wastewater is mainly composed of water containing anthropogenic wastes that are rich in nutrients such as carbon, nitrogen and phosphorous. The cost for biological treatment of wastewater is increasing globally due to the population growth in urban cities. In general, the activated sludge (AS) process is a biological nutrient removal process used in wastewater treatment plants (WWTPs). The AS is composed of different microorganisms in which bacteria play a crucial role in wastewater treatment (WWT). During the process, air is bubbled to supply oxygen and methanol is added to improve nitrogen removal, which is released as a gas. Phosphorous is removed in the expense of precipitation chemicals. Altogether, the current process requires electrical energy, precipitation chemicals, handling of excess sludge and it emits carbon dioxide (CO2) as a by-product. This process is still in practise in the WWTPs since 1914 although numerous modifications are implemented to meet the stringent regulations in the European Union and globally.

    Microalgae are microorganisms that perform photosynthesis like plants. They are green and reproduce fast using available nutrients (nitrogen and phosphorous) and CO2 from their environment in the presence of light. As a result of photosynthesis, oxygen is released as waste gas. The synthesised oxygen during this process can be implemented to support the AS bacteria that leads to the microalgae activated sludge (MAAS) process. The main advantage is combined removal of nutrients.

    The vision of the research is to implement the indigenous microalgae cultivation in activated sludge process to consume CO2 and recover the nutrients from wastewater. This study is performed to improve the understanding of the process such as: light utilisation, nutrient removal and recovery of the biomass from wastewater in closed photo-bioreactors. Photo-bioreactors are vessels where the cultivation is carried out in the presence of light. At first, the influence of the light spectrum on micro-algal cultivation is investigated for photosynthetic growth. This is followed by operational challenges of the microalgae cultivation during the AS process. The process is experimentally performed in the photo-bioreactors with different treatment time of the raw wastewater. The results showed that 2 - 6 days of treatment time can be used for reducing nutrients in wastewater if the process is optimised further. Also, nutrient ratio is analysed for the availability of the micro-algal growth. Furthermore, the biogas potential of MAAS showed a biogas yield of about 60-80% within 5 to 9 days.

    At last, the experimental verification of chemically precipitated wastewater showed limitation of phosphorous for micro-algal growth. Additionally, the optimal oxygen supply through light response is verified for photo-bioreactors. The outcome of this study shows that knowing the right conditions can lower the treatment time. By doing so, a stable nutrient removal and reduction of precipitation chemicals can be established as well as a better recovery of valuable nutrients as phosphorous and nitrogen.

  • 5.
    Anbalagan, Anbarasan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Lindberg, Carl-Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Influence of light intensity and phosphorous on microalgae activated sludge in phosphate precipitated conditionManuscript (preprint) (Other academic)
  • 6.
    Annaduzzaman, Md.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Deshpande, Paritosh Chakor
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Ersoz, M.
    Lazarova, Z.
    Chitosan biopolymer: a treatment option for uranium(VI) removal from drinking waterManuscript (preprint) (Other academic)
  • 7.
    Annaduzzaman, Md.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Ersoz, M.
    Lazarova, Z.
    Evaluation and optimization of chitosan biopolymer as an adsorbent for arsenic(V) in drinking watert treatmentManuscript (preprint) (Other academic)
  • 8.
    Annaduzzaman, Md.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Ersoz, M.
    Lazarova, Z.
    Characterization of a chitosan biopolymer and arsenate removal for drinking water treatment2014In: One Century of the Discovery of Arsenicosis in Latin America (1914-2014): As 2014 - Proceedings of the 5th International Congress on Arsenic in the Environment, CRC Press, 2014, 745-747 p.Conference paper (Refereed)
    Abstract [en]

    Chitosan biopolymer with a deacetylation degree of 85%, was assessed for its capability to adsorb As(V) from drinking water by batch experiments. To characterize the chitosan biopolymer, chitosan was analyzed by FTIR and SEM. The results showed that chitosan is an effective and promising sorbent for As(V) from drinking water. From the batch tests, results showed a maximum adsorption of 355 μg/L of As(V) with 1.18 μg g-1 adsorption capacity at pH 6. The kinetic data, obtained at pH 6 could be fitted with pseudo-second order equation (adsorption capacity: 0.923 μg g-1) and the process was suitably described by a Freundlich (R2 = 0.9933) model than by a Langmuir model (R2 = 0.9741). The results above indicated that chitosan is a very favorable sorbent for As(V) removal from aqueous solution.

  • 9.
    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.

  • 10. Asim, Muhammad
    et al.
    Kumar, N. T. Uday
    Martin, Andrew R.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Feasibility analysis of solar combi-system for simultaneous production of pure drinking water via membrane distillation and domestic hot water for single-family villa: pilot plant setup in Dubai2016In: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 57, no 46, 21674-21684 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents the feasibility study of installation of a solar-driven integrated MD desalination system for simultaneous production of pure drinking water and solar domestic hot water in United Arab Emirates (UAE) for a single-family villa comprising of 4-5 persons. In order to satisfy the current and future demand of water for domestic purposes, the desalination of seawater is considered to be one of the most effective and strategic technique in UAE. The stress on the underground water aquifers, rapid industrial growth, and increase in urban population in UAE results in the tremendous increase in fresh water demand during the past few decades. Since the local municipalities also provide the desalinated fresh water to the people but they mostly rely on bottled water for drinking purpose. In this paper, the pilot setup plant is designed, commissioned, and installed on site in UAE using air gap membrane distillation desalination process to fulfill the demand of 15-25 L/d of pure drinking water and 250 L/d of domestic hot water for a single-family villa. Experimental analyses have been performed on this setup during summer on flat plate solar collectors having different aperture areas (Experiments have been performed for aperture area of 11.9 m(2) in this research study for feasibility purpose). The average hot-side temperature ranges from 50 to 70 degrees C and average cold-side temperature of 35 degrees C.

  • 11.
    Asplund, Malin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Mark- växtsystem för behandling av lakvatten: utvärdering av reningseffekter vid Häradsuddens deponi2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    En av de viktigaste miljöaspekterna när det gäller deponering av avfall är utsläpp till vatten. Tidigare leddes lakvatten från de flesta deponier till kommunala reningsverk, men på senare tid har trenden gått mot allt mer lokala lösningar i mark- växtbaserade system.

    Vid Häradsuddens deponi i Norrköpings kommun har Econova mellan åren 2007 och 2011, i etapper, anlagt ett kombinerat system med lakvattenrecirkulering, luftad damm, intermittent översilning samt våtmark för rening av lakvattnet. Syftet med denna studie var att klarlägga vattenbalans och reningsfunktion för Häradsuddens reningssystem samt ge förslag på eventuella förbättringar.

    Resultaten i undersökningen tyder på en avsevärt högre belastning på våtmarken än de kända flöden som pumpas till lakvattensystemet, vilket tyder på utläckage av lakvatten från deponin. Reningssystemet klarade dock med god marginal reningskraven avseende halt för NH4-N och Ptot. Begränsande för möjligheten att släppa vattnet till recipient är halten TOC. Med anledning av lakvattnets sammansättning samt de förhållandevis höga halterna i tillrinnande vatten kan det bli svårt att komma ner i TOC-halter som säkrar möjlighet till utsläpp av behandlat lakvatten.

    Den areaspecifika reningen varierade beroende på om hänsyn togs till förmodat inläckage. Den areaspecifika reningen avseende NH4-N och Ntot var i princip obefintlig om ingen hänsyn togs till inläckage av lakvatten medan den var 80 respektive 50 g/m2·år om en beräkning av möjligt inläckage räknades med. När det gäller Ptot ökade avskiljningen från 1 till 2 g/m2·år vid hänsyn tagen till inläckage. Avskiljningen var något låg jämfört med etablerade våtmarker, men borde kunna öka med tiden.

    Analysunderlag för den luftade lakvattendammen och översilningen är otillräckligt och osäkert för att det ska kunna gå att dra några långtgående slutsatser avseende reningseffekt för dessa delar. De bedöms dock kunna ha potential för att öka avskiljningen, varför en noggrann utredning av reningseffekt och olika driftstrategier för lakvattendammen och översilningen rekommenderas.

  • 12.
    Assefa, Edom
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Ngabonziza, Bertrand
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering.
    Dagvattenhantering i urban miljö: Komplettering av befintliga avvattningssystem i Hemlingby2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this study is to propose appropriate solutions that can complete Hemlingbys existing stormwater treatment systems. The solutions presented in this study has been developed with regards to the current situation, which includes water drainage systems and ponds. The study includes a survey of the current stormwater management within the district, as a result, the authors have localized two problem areas that should be investigated, i.e. are Hemlingbybäcken and Kryddstigen. The stormwater recipient i.e. Hemlingbybäcken is affected by human activities. Contaminates that affect the stream consist mainly of copper, lead and zinc. Due to the lack of stormwater storage capacity problems associated with stormwater flooding occurred from nearby buildings and industrial areas. Kryddstigen is an area in the district where business in technology and trade are located, these activities contribute to pollution that degrades groundwater and recipient conditions. The northern part of Hemlingby consist mostly of hard surfaces, which reduces the possibility of a natural infiltration of rain water, this in turn has caused an increased risk of flooding in the area. Gävle municipality have through earlier investigations identified some of the problems and tried to prevent them by implementing ponds that can delay incoming stormwater. Follow-up works proves that the ponds serve a larger catchment area than previously estimated, which adverse the ponds efficiency. Capacity problems have therefore arisen, for instance wetland ponds are sized to handle 10-yearsrain from a catchment area of 19 hectares. However, the existing wetland ponds can only handle a 2-yearsrain from a catchment area of 2400m3. This study presents open stormwater management as alternative solution, this has been proposed based on existing sewerage systems and ponds. Open stormwater solutions are applied mostly in urban environment to delay and locally dispose stormwater. This is done by vegetation which makes it possible to achieve a natural infiltration. The public can also take use of open stormwater solutions by turning an unattractive city to a beautiful one. It can also be beneficial to the community because open stormwater solutions contribute with an aesthetically pleasing environment and increasing biodiversity. The alternatives are described as follows: Green roofs, permeable ground surfaces, ditch with macadam basin and, rain gardens. These solutions are then assessed together with the existing solutions based on internal and external aspects concerning stormwater management. External aspects include legislation and stormwater policy, internal aspects take into account factors such as economy, technology, social and environment conditions. Assessment methodology that are presented in this study aims to evaluate and prepare documentation that is relevant for decision- making and the development of technical solutions based on the current situation. The evaluation method used in this study is inspired by PESTEL- analysis model. This method has been adapted to assess stormwater solutions. An overall description of what a PESTEL- analysis is given in this study as well as the interpretation and application of the assessment method. The result for single alternatives is presented and discussed with respect to existing solutions in the area of this study.

  • 13.
    Benselfelt, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Biotechnology. Linköping University, The Institute of Technology.
    Flow Cytometry Sensor System Targeting Escherichia Coli as an Indicator of Faecal Contamination of Water Sources2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Poor water quality is a global health concern affecting one billion people around the world. It is important to monitor water sources in order to maintain the quality of our drinking water and to avoid disease outbreaks. Targeting Escherichia coli as a faecal indicator is a widely used procedure, but the current methods are time consuming and not adequate to prevent spreading of faecal influence.

     

    This Master thesis demonstrates the development of a near infrared fluorescence flow cytometer sensor system targeting Escherichia coli, using fluorescently labeled chicken IgY antibodies. The near infrared light was chosen to avoid fluorescence from blue-green algae that are present in the water source.

     

    The hardware was developed with a 785  nm laser line to detect Alexa Fluor 790 labeled antibodies, using a photomultiplier tube or two different CMOS cameras. The antibodies were labeled using a commercial labeling kit, and evaluated using antibody binding assays and the developed hardware.

     

    The IgY antibodies were successfully labeled with Alexa Fluor 790 and the function was maintained after the labeling process. The result demonstrates the principles of the sensor system and how it solved to the problem with fluorescence from blue-green algae. An aperture was used to overcome the suboptimal laser and filter setup, and to increase the sensitivity of the system. However, only a small fraction of the cells could be detected, due to challenges with the focal depth and loss of sensitivity in the photomultiplier tube at near infrared wavelengths. Further development is required to create a working product.

  • 14.
    Bercoff, Alexandra
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology.
    Investigation of the treatment process at Kungsberget's wastewater treatment plant under periods of irregular and low loads2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    At Kungsberget ski-resort in Gävleborg county all wastewater produced at the facility is treated on-site. The treatment takes place at their own wastewater treatment plant in a so-called Sequence Batch Reactor (SBR), which has been in operation for about a year before this study. Kungsberget AB is currently in charge of the facility but their goal is to hand responsibility over to Sandviken Energy AB. In order for this handover to occur Kungsberget has to produce three approved treatment results. This means that the concentrations of BOD7 needs to lie under 0.3 mg/l and total phosphorous under 10 mg/l in the effluent water for three consecutive samples. The results show momentaneous values. These limits are stated in the permit Kungsberget received from the Environmental Protection Division. Kungsberget has had problems with high and fluctuating phosphorous concentrations and therefore the transfer has not yet taken place.

    In this project several parameters have been analysed in order to obtain an overview of prevailing influent and effluent concentrations. Some of the parameters that have been analysed are; phosphorous, nitrogen, BOD7, suspended solids and pH. A lot of time and effort has been put into elucidating operational routines at the wastewater treatment plant (WWTP) and gaining knowledge from available literature regarding different parameters’ effect on treatment results.  

    Kungsberget has had problems adapting operating routines and reaching stable treatment results as the load is highly effected of seasonal fluctuation. This has not been taken into account earlier and the WWTP has been operated in the same manner all year around. Suggestions to how operating routines can be modified in to better meeting the needs have been produced and alternative treatment methods have been presented in the report. Two of the suggestions include biological phosphorous removal and adding carrier media to increase bacteria growth.

    An aerobic solids retention time has been calculated in order to evaluate whether nitrifying bacteria have enough time for grow and maintain a stable population. The calculation was carried out by measuring suspended solids and aeration time and the result was a solids retention time of approximately 6 days.

  • 15.
    Bhattacharya, Prosun
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Hossain, Mohammed
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Jacks, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Ahmed, K. M.
    Hasan, M. A.
    Von Brömssen, M.
    Groundwater arsenic pollution: A conceptual framework for sustainable mitigation strategy2014In: One Century of the Discovery of Arsenicosis in Latin America (1914-2014): As 2014 - Proceedings of the 5th International Congress on Arsenic in the Environment, CRC Press, 2014, 881-885 p.Conference paper (Refereed)
    Abstract [en]

    Tubewells installed by local drillers, provide access of drinking water in rural Bangladesh. Significant proportion of these wells contains arsenic (As) above the WHO guideline and the Bangladesh Drinking Water Standard. Various attempts for mitigation at household and community scale have resulted in limited success, but through the local driller's initiatives, the tubewells are the source of priority drinking water supply. We have developed a concept of Sustainable Arsenic Mitigation (SASMIT) to identify and target the safe aquifers through detailed hydrogeological studies for scientific validation of the water quality with respect to the color of the shallow sediments as perceived by local drillers. Together with water quality monitoring, we have also targeted the Intermediate Depth Aquifers (IDA) for providing As-safe and low manganese (Mn) water. SASMIT intervention logic also considered the relevant socio-economic scenario, such as household distribution, poverty issues and available safe water access for prioritizing safe well installation.

  • 16.
    Bhattacharya, Prosun
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Jacks, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. International Groundwater Arsenic Research Group.
    von Brömssen, Mattias
    Department of Soil and Water Environment Ramböll Sweden AB.
    Targeting Arsenic-Safe Aquifers in Regions with High Arsenic Groundwater and its Worldwide Implications (TASA)2015Report (Other academic)
  • 17.
    Biswas, Ashis
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mukherjee, Abhijit
    Nath, Bibhash
    Alexanderson, Helena
    Kundu, Amit K.
    Chatterjee, Debashis
    Jacks, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Shallow hydrostratigraphy in an arsenic affected region of Bengal Basin: Implication for targeting safe aquifers for drinking water supply2014In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 485, 12-22 p.Article in journal (Refereed)
    Abstract [en]

    To delineate arsenic (As) safe aquifer(s) within shallow depth, the present study has investigated the shallow hydrostratigraphic framework over an area of 100 km(2) at Chakdaha Block of Nadia District, West Bengal. Drilling of 29 boreholes and subsequent hydrostratigraphic modeling has identified three types of aquifer within 50 m below ground level (bgl). Aquifer-1 represents a thick paleochannel sequence, deposited parallel to the River Hooghly and Ichamati. Aquifer-2 is formed locally within the overbank deposits in the central floodplain area and its vertical extension is strictly limited to 25 m bgl. Aquifer-3 is distributed underneath the overbank deposits and represents an interfluvial aquifer of the area. Aquifer-3 is of Pleistocene age (similar to 70 ka), while aquifer-1 and 2 represent the Holocene deposits (age <951 ka), indicating that there was a major hiatus in the sediment deposition after depositing the aquifer-3. Over the area, aquifer-3 is markedly separated from the overlying Holocene deposits by successive upward sequences of brown and olive to pale blue impervious clay layers. The groundwater quality is very much similar in aquifer-1 and 2, where the concentration of As and Fe very commonly exceeds 10 mu g/L and 5 mg/L, respectively. Based on similar sediment color, these two aquifers have jointly been designated as the gray sand aquifer (GSA), which constitutes 40% (1.84 x 10(9) m(3)) of the total drilled volume (4.65 x 10(9) m(3)). In aquifer-3, the concentration of As and Fe is very low, mostly <2 mu g/L and 1 mg/L, respectively. This aquifer has been designated as the brown sand aquifer (BSA) according to color of the aquifer materials and represents 10% (4.8 x 10(8) m(3)) of the total drilled volume. This study further documents that though the concentration of As is very low at BSA, the concentration of Mn often exceeds the drinking water guidelines.

  • 18.
    Biswas, Ashis
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Gustafsson, Jon Petter
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Neidhardt, Harald
    Halder, Dipti
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Kundu, Amit K.
    Chatterjee, Debashis
    Berner, Zsolt
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Role of competing ions in the mobilization of arsenic in groundwater of Bengal Basin: Insight from surface complexation modeling2014In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 55, 30-39 p.Article in journal (Refereed)
    Abstract [en]

    This study assesses the role of competing ions in the mobilization of arsenic (As) by surface complexation modeling of the temporal variability of As in groundwater. The potential use of two different surface complexation models (SCMs), developed for ferrihydrite and goethite, has been explored to account for the temporal variation of As(III) and As(V) concentration, monitored in shallow groundwater of Bengal Basin over a period of 20 months. The SCM for ferrihydrite appears as the better predictor of the observed variation in both As(III) and As(V) concentrations in the study sites. It is estimated that among the competing ions, PO43- is the major competitor of As(III) and As(V) adsorption onto Fe oxyhydroxide, and the competition ability decreases in the order PO43- >> Fe(II) > H4SiO4 = HCO- (3.) It is further revealed that a small change in pH can also have a significant effect on the mobility of As(III) and As(V) in the aquifers. A decrease in pH increases the concentration of As(III), whereas it decreases the As(V) concentration and vice versa. The present study suggests that the reductive dissolution of Fe oxyhydroxide alone cannot explain the observed high As concentration in groundwater of the Bengal Basin. This study supports the view that the reductive dissolution of Fe oxyhydroxide followed by competitive sorption reactions with the aquifer sediment is the processes responsible for As enrichment in groundwater.

  • 19.
    Bjarne, Katrin
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control.
    Optimerad förfällning med hydrolys och fermentation av primärslam för utvinning av kolkälla till efterdenitrifikation.2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Water treatment is costly, from both an economic and environmental point of view, since the need for precipitation chemicals, carbon sources and energy is high. It is therefore desirable to look for alternative solutions that enable plants to be more self-sustaining.

    Hammarby Sjöstadsverket is a pilot plant for wastewater treatment located in Henriksdal, a southeastern neighborhood of Stockholm. The plant is owned by IVL, Svenska Miljöinstitutet and Kungliga Tekniska Högskolan (KTH). Since the pilot plant was built in 2002, several different cleaning techniques have been evaluated with focus on striving for eco-friendly and eco-adapted systems. For instance, a pre-precipitation technique, so-called three step precipitation have been evaluated. The three step precipitation implicates that a metal salt followed by two different polymers are added in the flocculation chamber in the particular order to thereby enable to reduce a higher content of the organic material. In previous precipitation tests at Hammarby Sjöstadsverket, one managed to remove up to 90 % of the organic material using the three step precipitation (IVL, Hammarby Sjöstadsverket, 2011). This can be compared to a removal of only 75 % with ordinary pre-precipitation.

    This thesis aims to validate already obtained results within three step precipitation and with biological hydrolysis of primary sludge, extract a carbon source for post-denitrification containing as high concentrations of Volatile Fatty Acids (VFA) as possible and to investigate the cost of a wastewater treatment plant with three step precipitation, biogas generation and collection of internal carbon source from primary sludge at an upscaling corresponding to 100,000 person equivalents.

    Precipitation experiments were carried out in pilot scale with the precipitation chemicals, PAX-XL 36, combined with a low molecular weight organic polymer, Purfix-120, followed by a high molecular weight inorganic polymer, Super Flock C-494. The purpose of the three step precipitation was to validate the already produced results within three step precipitation and thus separate as large amounts of organic material as possible in the precipitation so that a primary sludge containing a high chemical oxygen demand (COD) can be obtained.Two different dosages of Purfix-120 were tested: 45 and 60 g/m3. The best reduction of COD and phosphorus were obtained when 193 g/m3 PAX XL-36 was combined with 60 g/m3 Purfix-120 and 0.025 g/m3 Super Flock C-494. Hereby a COD reduction of 75 % and a total phosphorus removal of 83 % were obtained.

    By hydrolysis of primary sludge in batch experiments Total Solid (TS) concentrations of 1, 2 and 3 % and residence times of up to eight days were examined. The purpose of the hydrolysis in this case was to investigate which TS concentration and residence time that gave the highest production of VFA. The experiments showed that a TS concentration of 3 % produced the highest amount of VFA and that the VFA production of the three different TS concentrations peaked at the second day. The VFA and COD production increased linearly for the three TS concentrations up until day five. After day five the COD and VFA production, for the TS concentrations of 1 and 2 %, started to decrease slightly. However TS 3 % did not show the same declining trend for VFA. Furthermore the daily ammonium and pH were investigated.  As the VFA and COD concentration increased the ammonium concentration increased as well. pH had overall a  decreasing trend.

    Four different denitrification tests were performed in batch experiments with the extracted hydrolyzate. The added COD content from the hydolyzate was either 3.3 or 4 times the initial nitrate concentration. The denitrification tests showed denitrification rates between 4.3 and 7 mg NO3-N / g volatile suspended solids * h with carbon-nitrogen ratios (C/N ratio) between 3.9 and 12.3 mg COD/mg NO3-N. The lowest C/N ratio received the lowest denitrification rate. However, it could not be concluded that the maximum C/N ratio had the highest denitrification rate.

    Futhermore the financial aspects were examined in order to investigate the cost of a wastewater treatment plant with three step precipitation, biogas generation and collection of internal carbon source from primary sludge at an upscaling corresponding to 100,000 person equivalents. The extraction of an internal carbon source would, despite loss of biogas production, be economically beneficial. Gain, in terms of not having to purchase an external carbon source, in this case ethanol, amounts to the amount of the biogas loss. The three step precipitation chemical costs were the largest item, amounting to 8,060,000 SEK. This cost versus less energy utilization in the biological step was also examined. In this case the savings in the biological step amounted to about 1/8 of precipitation chemical cost. Since the three step precipitation only managed to remove 75 % of the COD, a removal which corresponds to an ordinary pre-precipitation, the three step precipitation is considered to be economically unfavorable as it involves additional costs of polymers. Instead the three step precipitation should be replaced with a pre-precipitation.

    In summary it can be stated that an internal carbon source in the form of hydrolyzed primary sludge could replace an external carbon source in a functional way. However, steps must be taken to minimize the production of ammonium during sludge hydrolysis. From an economic perspective, the extraction of an internal carbon source would only be economical favorable if the three step precipitation is replaced with pre-precipitation.

     

  • 20. Björk, Anders
    et al.
    Samuelsson, Oscar
    Carlsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Chistiakova, Tatiana
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Zambrano, Jesús
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Detecting Anomalous Air Flow-ammonia Load Ratios, Using Gaussian Process Regression2015In: Proc. 9th IWA Symposium on Systems Analysis and Integrated Assessment, 2015Conference paper (Other academic)
    Abstract [en]

    In this paper we propose a method to detect abnormal air flow-ammonia load ratios in active sludge basins. The purpose is to detect faulty sensors and process disturbances affecting the air flow-ammonia load ratio. The method is based on Gaussian process regression, and is evaluated on plant data. Results indicate that drift in an ammonia on-line sensor, over flow during storm events and changed sludge properties can be detected by the proposed method.

  • 21.
    Bodlund, Ida
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Coagulant Protein from plant materials: Potential Water Treatment Agent2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    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. 

  • 22.
    Bohlin, Ulrika
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control.
    Comparing Cork Filters to Conventional Sand Filters: A Pilot Study of Process Water Treatment2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Process water is used for cooling and for transporting material in all kinds of industries. To clean the water for reuse, various types of filters can be used. Many conventional process water treatment plants incorporate sand filters, which readily clean the water from suspended matters. However, at some circumstances the sand filters do not remove high enough concentrations of metals.

    This master thesis compares the water treatment abilities of activated cork, produced by Spikes & Cogs AB, to those of the sand filters used at steel making company Ovako Hofors AB in Hofors. As an on-site pilot study, the thesis investigates the cleaning capacity of three types of activated cork filters: Fats, Oils and Solvents (FOSS) filter, Fast Acting Digesting Enzymes (FADE) filter, and Metal Adsorption and Concentration (MAAC) filter.

    The cork filters were compared to the sand filters during normal operation and, because of previous problems with the stability of the sand filter performance, during stress tests. The results show that the cleaning capacity of the sand filters is higher than the cleaning capacity of the cork filters at normal operation. At the conditions of the stress tests, at which the sand filters do not function, the cleaning capacity of the cork filters was somewhat lowered but was still well within acceptable limits.

    An important result from the experiments is that the cork filters neutralize the pH. The sand filters are sensitive to changes in the pH, meaning that the cork filters could function as a buffering unit prior to the sand filters.

  • 23.
    Bohman, Anna
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    I vått och torrt? : En studie av nationell vattenkatastrofgrupp VAKA: Underlag till den statliga dricksvattenutredningen2016Report (Other academic)
    Abstract [sv]

    Den här rapporten har studerat VAKA-gruppens verksamhet med speciellt fokus på hur de som larmat VAKA upplevt hjälpen, vilka konsekvenser som kunnat undvikas genom VAKA:s stöd samt hur insatserna skulle kunna organiseras och finansieras framöver. Studien utgår från 26 intervjuer med aktörer som larmat VAKA någon gång mellan 2010 och 2015.

    Sammanfattningsvis kan det konstateras att de intervjuade kommunerna upplever att VAKA erbjuder en synnerligen effektiv och professionell hjälp som bidragit till att olycksförloppen kunnat både mildras och förkortas avsevärt. Man har bistått med kvalificerad experthjälp vad gäller lägesanalys, provtagningar och analyser, bistått i organisationen av krisledningen och även förmedlat erfarenheter och kunskaper gällande media hantering samt kommunikation gentemot allmänheten. VAKA har dessutom tillgång till ett brett kontaktnät och har i de fall då man själv inte besitter rätt expertis snabbt kunnat förmedla kontakt med rätt person/instans. De intervjuade kommunerna har framhållit att man fått mental stöttning av VAKA i situationer som varit belastande för krisledningen. Att ha tillgång till erfarna människor som bollplank och som en part i diskussionen i ett kritiskt läge framhålls som otroligt viktigt för de inblandade.

    Flertalet av de intervjuade bedömer att det kan finnas en viss betalningsvilja för VAKA:s tjänster på kommunal nivå men ser en överhängande risk med att vissa kommuner eventuellt avvaktar en kontakt om denna är avgiftsbelagd. I sammanhanget bör man också beakta att andra aktörer än kommuner i dagsläget är berättigade att nyttja VAKA:s tjänster varför en exklusiv kommunavgift inte framstår som en optimal lösning framgent.

    Ingen av de intervjuade ser någon fördel med att VAKA verksamhet skulle organiseras på privat konsultbasis alternativt ersättas med regional kompetensutveckling. Det senare alternativet menar man känns inte realistiskt med tanke på att VAKA besitter vad som måste betraktas som nationell spetskompetens och att det skulle vara svårt att sprida denna till alla regioner.

    Förslag på verksamhetens utveckling som framkommit gäller bl.a. tillgången till nödvattenutrustning där tillgängligheten skulle kunna förbättras både via tätare avstånd mellan lagren samt en koordinering av samutnyttjande av resurser mellan kommuner. Man tror även att kännedomen om VAKA skulle kunna förbättras via informationsinsatser.

    Ytterligare ett förslag på verksamhetens utveckling gäller tillgång till laboratorier där man föreslår att VAKA alternativt Livsmedelsverket skulle administrera en central upphandling för att säkerställa att det alltid finns tillgång till laboratorieresurser.

    Baserat på rapportens samlade bedömning rekommenderas det att VAKA gruppens verksamhet även fortsättningsvis bör bedrivas i sin nuvarande form men med en fast finansiering från näringsdepartementet som möjliggör en mer långsiktig planering av verksamheten.

    Avslutningsvis bör det återigen understrykas att effekterna av framtida klimatförändringar medför att riskerna för dricksvattenförsörjningen ökar och att antalet incidenter kopplat till dricksvattenförsörjning med stor sannolikhet kommer att öka. Behovet av VAKA-gruppens tjänster blir därmed större i framtiden.

  • 24. Borghei, Seyed Mahmood
    et al.
    Nekooie, Mohammad Ali
    Sadeghian, Hadi
    Ghazizadeh, Mohammad Reza Jalili
    Parvaneh, Ali
    Yang, James
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Hydraulic Engineering.
    Javaheri, Amir
    Kabiri-Samani, Abdorreza
    Discussion: Triangular labyrinth side weirs with one and two cycles2016In: Proceedings of the Institution of Civil Engineers: Water Management, ISSN 1741-7589, E-ISSN 1751-7729, Vol. 169, no 3, 111-114 p.Article in journal (Other academic)
  • 25. Brenner, A.
    et al.
    Persson, K. M.
    Russell, L.
    Rosborg, Ingegerd
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Kozisek, F.
    Technical and mineral level effects of water treatment2015In: Drinking Water Minerals and Mineral Balance: Importance, Health Significance, Safety Precautions, Springer, 2015, 103-117 p.Chapter in book (Other academic)
    Abstract [en]

    Reverse Osmosis is used for desalination of especially sea water in areas suffering from water shortage, and there are thousands and thousands of desalination plants around the world and more to come. The produced high–purity water tends to be corrosive, and lacks minerals, causing decreased daily intake and loss of minerals from the body. Thus, such water needs re–mineralization. Water with toxic substances is harmful, and is also often treated with RO. There are indexes to be used as guides to choose re–mineralization method after RO. However, mineral balance is not reached by remineralization, as only concentrations of calcium and bicarbonate, and in some cases magnesium is increased. Treatment with dissolution of dolomitic–calcitic limestone or other limestone with low levels of toxic elements is preferable. Hard water, on the other hand, may cause scaling, and is often softened, making the concentrations of calcium and magnesium low or extremely low. General advices on choice of treatment method to preserve or improve the mineral content and mineral balance of a water is presented in the chapter.

  • 26.
    Cameli, Fabio
    KTH, School of Chemical Science and Engineering (CHE).
    Microbial Fuel Cell for Waste Water Treatment2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Microbial Fuel Cell is a novel technology that can be used for a waste water treatment in order to simultaneously remove carbonaceous matter and nitrogen while producing electrical power.

    Even if it is not an established technology so far, MFC could be a cost effective option for waste water treatment and the major challenge of this process will be the device scale-up. Exoelectrogenic bacteria are capable of converting the chemical energy of organic matter into electrical energy by transferring the electrons produced in the oxidation to the anode electrode.

    This project focused on developing a single device for nitrification, denitrification and carbon removal. Two double air-cathode single chamber MFCs are used to test the feasibility of this process that could replace the biological unit in a waste water treatment train.

    The cells tested in this study were manufactured with the purpose of achieving a high surface area on both the anode electrode (vitreous carbon foam) and the air-cathode electrodes (metallic mesh with diffusion layer and active layer) with different catalysts for the reduction reaction (cobalt and platinum). The bacterial biofilm growth is a fundamental step and the cells Open Circuit Potential was monitored during all the start-up period to determine the microorganism acclimation: a three days lag period was observed in both cells before the potential rise. The second cell was forced to reach higher voltage through an anode polarization and that seems to positively affect the biofilm stability at lower voltages transferring a greater amount of electrons and hence obtaining a higher current and power generation. For this reason after three weeks of inoculation the second cell reached an open circuit potential of 0.76 V which is a promising value for such a system.

    Electrochemical and biological tests were conduced in order to test the power production of the cell and the substrate removal from the waste water. Polarization curves were used to evaluate power generation (and the maximum production under a specific external load) and the cell voltage trend which is characterized by activation and ohmic losses: 32 mW/ and 41 mW/  are the power density normalized by cathode surface (72 ) reached by respectively first and second cell. The experimental conditions were varied from low to high temperature and from low to high inlet flow rate but the most affecting phenomenon seems to be the biofilm formation since significant voltage drops were noticed after long closed circuit operation. Higher cell voltage characterized the second cell thanks to more active cathode (platinum catalyst used) and more negative bacterial biofilm but a bigger drop in current generation over time affects the system performance and the most reliable reason is the shorter acclimation time compared to the first cell.

    Cyclic voltammetry tests were carried out on both electrodes to study the potential range of activity and determine an optimal operational voltage despite of mass transport or kinetic limitations.

    Substrate removal tests at different retention times in power generation conditions (external load 100 Ω) showed a relatively high total nitrogen consumption (maximum 72.2 %) for the first cell while lower values were achieved by the second system meaning that a longer acclimation period is beneficial for nitrifying and denitrifying bacteria to thrive on the cathode biofilm.

    Effluent pH level are almost similar to the initial values probably because of nitrification and denitrification protons offset.

  • 27.
    Carlsson, Bengt
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Diehl, Stefan
    Zambrano, Jesús
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Analyses of Activated Sludge Processes Consisting of a Plug-Flow Reactor and a Non-ideal Settler2015In: Proc. 9th IWA Symposium on Systems Analysis and Integrated Assessment, 2015Conference paper (Other academic)
    Abstract [en]

    An activated sludge process (ASP) consisting of a plug-flow reactor (PFR) and a non-ideal settler is modelled and analysed. One soluble substrate component and one particulate biomass are assumed. The biomass growth rate is described by a Monod function. The settler model includes hindered settling and compression. A model describing the steady-state behaviour of the ASP is derived which constrains the settler to work with a fixed sludge blanket height in the thickening zone. The model provides new understanding for these types of ASPs and may be used for novel design schemes. The numerical example suggests that the steady-state solutions of the ASP give a one-parameter family of solutions, where the parameter is the recycle ratio r.

  • 28.
    Carlsson, Bengt
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Zambrano, Jesús
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Analysis of simple bioreactor models: A comparison between Monod and Contois kinetics2014In: Proc. IWA Conference on Activated Sludge – 100 Years and Counting, IWA Publishing, 2014Conference paper (Refereed)
    Abstract [en]

    In this paper, an analysis of simple bioreactors in series is presented. The bioreactors are analysed for growth kinetics of the biomass described by a Monod and a Contois function. In particular, it is studied how the effluent substrate concentration is depending on the influent substrate concentration during steady state. It is shown that by going from one to two bioreactors in series completely changes the process behaviour when the growth kinetics is described by a Monod function. It is also shown that a bioreactor described by Contois kinetics has a completely different behaviour compared with the Monod case.

  • 29.
    Carlsson, Bengt
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Zambrano, Jesús
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Fault detection and isolation of sensors in aeration control systems2016In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 73, no 3, 648-653 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, we consider the problem of fault detection (FD) and isolation in the aeration system of an activated sludge process. For this study, the dissolved oxygen in each aerated zone is assumed to be controlled automatically. As the basis for an FD method we use the ratio of air flow rates into different zones. The method is evaluated in two scenarios: using the Benchmark Simulation Model no. 1 (BSM1) by Monte Carlo simulations and using data from a wastewater treatment plant. The FD method shows good results for a correct and early FD and isolation.

  • 30.
    Carlsson, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Kartläggning av upphandlingsprocessen inom vatten- och avloppsbranschen – användning av livscykelkostnader i processen2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of public procurement is to create competitive markets and generate the bestpossible deal for the contracting authority. Public procurement should aim for long-termperspective, and there are tools to ensure that a long-term view is obtained. One tool is lifecycle costs (LCC), where product acquisition, ownership and settlement are considered. Aproduct that has a high investment cost but low operating costs, may be the most costeffectivepurchase. LCC is used to achieve an economic evaluation of different investmentoptions, discounted over the lifetime of the product. Life-cycle costing is an approach thatexplores the various investment options and is used to as a basis of discussion by theparticipants in the procurement process.

    The use of life-cycle costs, are expected to be useful for decision makers in the water andwastewater industry if they want to take long-term correct decisions. The problem is that noone has studied how a life cycle cost tool affects the decision-making process in publicprocurement within the water and wastewater industry and if it gives the client a gooddecision making basis. This study therefore aimed to find out how life cycle costs are used inpractice and how these can be used in practice, as an aid in the decision making process forwater and wastewater procurements. The study also aimed to find out how a life cycle costtool should be designed, by giving suggestions on conditions that must be taken into account.

    This thesis has been carried out on behalf of The meeting place for the industry in watertreatment (VARIM), with the aim to investigate the procurement process within the water andwastewater trade. It also studies how life cycle costs are used in the process. The study wascarried out in two steps, consisting of qualitative interviews, 27 individual interviews gaverise to a rich material, which was subject to further analysis. The interviewees had fivedifferent roles in the procurement process: client, purchaser, user, consultant and bidder. Thestudy was limited to investigating four types of municipalities: large cities, major cities,manufacturing municipalities and rural municipalities. The results from the interviews wereanalyzed based on theory from the literature study, the results from the data collection wereanalyzed.

    The results show that life-cycle costs in water and wastewater procurement are needed. Thereis also great potential for LCC as the majority of respondents were in favor of the use of LCC,primarily in the procurement of energy-using products or processes. A great difference inaccess to resources was identified between smaller clients and major clients, resulting in thesmaller clients not using life-cycle costs as a criterion. Also the results indicate that the use oflife cycle costs contributes to greater transparency in the procurement process and thereforedecreases risk of appeals. The study shows that follow up of life cycle cost in a contract is oneof the most difficult problems in procurement.

  • 31.
    Carlsson, Ulrika
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Avgång av lustgas från luftningsprocessen på Käppalaverket2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The requirements for wastewater treatment plants (WWTP) are gradually increasing, partly because of higher incoming loads, which in turn require a more efficient treatment process. In parallel with environmental and economic goals there are also desires to lower energy consumption without compromising the wastewater treatment. Furthermore, there is a demand on WWTP´s to alter eutrophication in aquatic systems through better nitrogen and phosphorus removal. An increasing number of WWTP´s have acquired biological nitrogen and phos-phorus removal. A by-product of this type of biological treatment is the formation of nitrous oxide, which is a potent greenhouse gas. But how large is the WWTP´s share of nitrous oxide to the total emissions? To answer this question an increasing number of WWTP´s around the world have begun to study the emission of nitrous oxide. Today it is still not entirely clear where in the process nitrous oxide forms and why. Studies have shown that the emissions are different from different sewage treatment plants, partly because the plants have different loads and treatment processes. It is therefore essential that more studies are made to get a better understanding of the emission mechanism. In the autumn 2011, measurements of nitrous oxide emissions were conducted on Käppala-verket on Lidingö in cooperation with IVL the Swedish Environmental Research Institute. The purpose of the measurements was mainly to get an indication of how much nitrous oxide Käppalaverket emits each year. In addition tests were also conducted on how emissions could be reduced by comparing two different aeration strategies, by keeping different constant levels of oxygen and by using ammonium-feedback. In this latter test correlations between nitrous oxide emissions and various process parameters were studied. The experiments with different control strategies are based on previous American studies that have demonstrated that the oxygen supply of nitrifiers may be crucial for how much nitrous oxide will be emitted. The results of this study show that Käppalaverket´s biological treatment process emits 5.5 tones N2O/year representing 0.3% of the incoming nitrogen. Attempts to compare two different aeration strategies did not fall out as expected due to process disturbances. Collected data have also been analyzed and compared, with focus on causal relationships of nitrous oxide emission. Any clear correlation between nitrous oxide and the studied process changes have not been detected. The study shows that low oxygen levels do not seem to produce more nitrous oxide.

    Keywords: Nitrous oxide, activated sludge process, nitrification, denitrification, greenhouse gas, sewage treatment

  • 32.
    Carlström, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Modellering av organiskt material i avloppsvatten vid mekanisk tillverkning av pappersmassa: Regressionsanalys baserad på COD- och TOC-analyser vid olika grader av blekning och raffinering2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I avloppsreningen på Hallsta pappersbruk i Hallstavik reduceras dagligen tonvis med organiskt material innan avloppsvattnet släpps ut i den intilliggande Edeboviken. Bruket är ett så kallat integrerat pappersbruk vilket innebär att man tillverkar både pappersmassan och pappret på plats. Det är främst vid framställningen av massa som det organiska materialet löses ut ur veden och hamnar i processvattnet som så småningom når brukets avloppsreningsverk. På bruket tillverkas papper i olika ljusheter, vilket kräver olika stora insatser i form av blekkemikalier så som väteperoxid och hydrosulfit (även känt som ditionit). Blekningen varierar över tid i produktionscykler och det är sedan tidigare känt att en ökad blekning av massan löser ut mer organiska föreningar. I framtiden förväntas andelen högblekta produkter öka, vilket sannolikt leder till ökad belastning på reningsverket. Det finns även planer på att öka andelen papper av sådan kvalitet som kräver att massan raffineras hårdare (så att den blir finare mald) och frågan har lyfts huruvida denna behandling leder till mer organiskt material till avloppet.

    Ökad kunskap om hur flödet av organiskt material till avloppet varierar är då detta skrivs (2012) värdefull i minst två tillämpningar på Hallsta pappersbruk. Den ena tillämpningen är vid utredningen av potentialen för en biogasanläggning på bruket, där det organiska materialet utgör en begränsande resurs vid framställningen av biogas, varför det vore värdefullt att veta hur stora mängder organiskt material som kan förväntas vid olika produktionsfall. Den andra tillämpningen är vid doseringen av kväve och fosfor i reningsanläggningen som görs för att mikroorganismerna som används för att rena vattnet ska kunna arbeta optimalt.

    Huvudsyftet med detta arbete var att skapa en modell för hur mängden organiskt material i olika avloppsströmmar beror på graden av blekning, samt i viss mån raffineringen. Det organiska materialet analyserades som TOC (Total Organic Carbon) och COD (Chemical Oxygen Demand). Ett tydligt samband mellan blekning med väteperoxid och mängden organiskt material i avloppet observerades i en av delströmmarna. Hydrosulfitblekning sågs inte öka mängden organiskt material i avloppsvattnet. En modell för den totala belastningen på avloppsreningsanläggning sattes också ihop, som utifrån planerad dosering av väteperoxid ger en uppskattning av halten TOC i inflödet till anläggningen. Modellen fångar upp den cykliska variation i TOC som observerades över tid, men lämnar lite att önska i fråga om absoluta nivåer.

  • 33.
    Chistiakova, Tatiana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Carlsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Zambrano, Jesús
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Samuelsson, Oscar
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Binary classifiers applied to detect DO sensor faults during washing events2015In: Proc. 2nd IWA Conference on New Developments in IT & Water, IWA Publishing, 2015Conference paper (Other academic)
    Abstract [en]

    In this paper, several classication techniques are applied for monitoring the status of DO sensors in wastewater treatment plants. In particular, DO sensors during washing events are studied and indication parameters from these events are used. The methods considered are the following: k-Nearest Neighbours, Radial Basis Function and Random Forest classiers. The result shows the comparison and the eligibility of the methods to detect a clogged DO-sensor.

  • 34.
    Chistiakova, Tatiana
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Zambrano, Jesús
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Carlsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Application of machine learning methods for fault detection in wastewater treatment plants2014In: Reglermöte, 2014Conference paper (Other academic)
  • 35.
    Chusova, Olga
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Nolvak, H.
    Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, Tartu 51014, Estonia.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Truu, J.
    University of Tartu, Estonia.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Oopkaup, K.
    University of Tartu, Estonia.
    Truu, M.
    University of Tartu, Estonia.
    Effect of pine bark on the biotransformation of trinitrotoluene and on the bacterial community structure in a batch experiment2014In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 35, no 19, 2456-2465 p.Article in journal (Refereed)
    Abstract [en]

    Pine bark, a low-cost industrial residue, has been suggested as a promising substitute for granular activated carbon in the on-site treatment of water contaminated with 2,4,6-trinitrotoluene (TNT). However, the complex organic structure and indigenous microbial community of pine bark have thus far not been thoroughly described in the context of TNT-contaminated water treatment. This two-week batch study examined the removal efficiency of TNT from water by (1) adsorption on pine bark and (2) simultaneous adsorption on pine bark and biotransformation by specialized TNT-biotransforming microbial inocula. The bacterial community composition of experimental batches, inocula and pine bark, was profiled by Illumina sequencing of the V6 region ofthe 16S rRNA gene. The results revealed that the inocula and experimental batches were dominated by phylotypes belonging to the Enterobacteriaceae family and that the tested inocula had good potential for TNT biotransformation. The type of applied inocula had the most profound effect on the TNT-transforming bacterial community structure in the experimental batches. The indigenous microbial community of pine bark harboured phylotypes that also have a potential to degrade TNT. Altogether, the combination of a specialized inoculum and pine bark proved to be the most efficient treatment option for TNT-contaminated water.

  • 36.
    Dahlström, Tove
    Sveriges lantbruksuniversitet, Institutionen för mikrobiologi.
    Nedbrytning av organiskt material och förekomst av svamp- och bakteriesamhällen i Uppsalaåsen2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In Sweden, drinking water is easy to access and often taken for granted. The drinking water systems have to be maintained in order to keep the high quality. The Uppsala esker, which is a part of the Uppsala municipality’s water system, provides a large number of the municipality’s population with drinking water. The Uppsala esker has been used to produce drinking water since 1956 by infiltrating water from the Fyris river into the esker. This reduces the amount of organic material in the water. A reduction is desirable since the organic material is causing odorous water and binds to substances that may harm people’s health.

    The reduction of organic material has been assumed to depend on degradation carried out by microorganisms above the esker’s groundwater table, dilution with additional groundwater and attachment of organic material to the esker’s material. However, recent studies have shown that only 10-15 % of the organic material is degraded above the groundwater table.

    The aim with this master thesis was to examine if the mineralization of the organic material in the anaerobic part of the Uppsala esker is greater than previously assumed. The size of the fungal and bacterial communities have also been examined as well as how microorganisms and the degradation of organic material relates to different chemical and physical factors in the soil.

    To get an understanding of the organic material’s degradability, soil was incubated and the aerobic respiration with gas chromatograph was measured. The bacteria and fungi were quantified using quantitative real-rime PCR. Various chemical and physical factors, such as the content of organic carbon and amount of aluminium, were already available. Pearson’s product-moment correlation coefficient (Pearson's r) was used to examine the the linear correlation between two variables. Wilcoxon’s rank score test was used to determine which of the differences between different sampling areas that were significant.

    The results showed that bacteria dominate in the Uppsala esker and the infiltration basins. Complex binding by iron- and aluminium compounds do not affect the degradation of organic matter, nor decrease the presence of fungi and bacteria in the esker and the infiltration basins. It seems as if the degradation rate’s sensitivity decreases with the depth. The amount of bacteria and fungi decreased with the distance to the infiltration basin, but not the quality of the organic material, if measured by the respiration rate divided by the amount of organic carbon. 

  • 37.
    Danielsson, Lina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Söderberg, Lisa
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Removal of chromium in wastewater with natural clays in southern Malawi2013Student paper other, 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To live a healthy life, people all around the world need access to safe water. A lot of industries,together with the fast growing population in Blantyre, a city in southern Malawi, pose a threat to theaccess of safe water for the citizens. Several of the industries in Blantyre release contaminated waterto the nearby streams. One serious pollutant emitted from a match factory is chromium (Cr),especially in the occurrence of Cr(VI) which is carcinogenic for humans. Earlier studies have shownthat the concentration of chromium in the match factory’s wastewater was higher than WHO:sguidelines. It has also been published that natural clay minerals can be used for adsorption of Cr(III).This study investigates the removal of Cr(VI) through the adsorption of Cr(VI) to clay minerals or byreduction of Cr(VI) to Cr(III) which is precipitated from solution.The laboratory work performed in this study includes both experiments for adsorption of Cr(VI) andreduction of Cr(VI) to Cr(III). The reducing agents investigated were two clays and Fe(II) sulfate. Foradsorption of negatively charged Cr(VI) compounds, the two clays where used at lower pH and themineral bauxite was also tried as adsorbent agent. Wastewater from the match factory was dilutedand mixed with the removal agents and the concentration of total chromium was measured beforeand after the mixing process. For the agent with highest potential for Cr(VI) removal, the optimalconditions due to pH, dosage of agents and contact time were inspected.None of the investigated reducing agents served its purpose which means that no Cr(VI) was reducedto Cr(III) in this study. The adsorption of Cr(VI) with clay 1 at lower pH was also not successful, butthe adsorption worked for clay 2 at lower pH and for bauxite. In the experiments bauxite adsorbed ahigher amount of Cr(VI) than clay 2. The adsorption with bauxite turned out to be independent interms of pH. The optimal conditions for bauxite in the experiments were with a dosage of 3.5 gbauxite in 50 mL wastewater and a contact time of 40 minutes. The results showed an adsorption of93 percent of total chromium with bauxite at optimal conditions.

  • 38. Davidsson, A.
    et al.
    Kjerstadius, H.
    Haghighatafshar, S.
    Fick, Jerker
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Olsson, M.
    Wachtmeister, H.
    Eriksson, E.
    Jansen, J. la Cour
    Effect of anaerobic digestion at 35, 55 and 60 degrees C on pharmaceuticals and organic contaminants2014In: Water Science and Technology, ISSN 0273-1223, Vol. 69, no 6, 1282-1288 p.Article in journal (Refereed)
    Abstract [en]

    The application of treated sewage sludge on farmland is a suggested method for recycling nutrients and reducing demand for commercial fertilizer. However, sludge needs to be safe from possible contaminants which can cause acute and long-term health and environmental problems. Residual pharmaceuticals and organic contaminants are mentioned as emerging threats since wastewater treatment plants are not designed to degrade these substances. The aim of this study was to screen and evaluate the presence, and reduction, of pharmaceuticals and polycyclic aromatic hydrocarbons (PAHs) during anaerobic digestion of mixed primary and waste-activated sludge at 35, 55 and 60 degrees C and during pasteurization at 70 degrees C. The study showed the difficulty of analysing pharmaceutical compounds in low concentrations in the sludge matrix. No general reduction of these compounds was seen during treatment, but for individual substances some reduction occured. The PAHs were generally not reduced during digestion or pasteurization, but for three substances (indeno[1,2,3-cd]pyreneand dibenzo[a,h] anthracene (analysed together) and benzo [g,h,i] perylene) reduction (up to 60%) during digestion was seen. Digestion at 35 and 55 degrees C resulted in about the same order of reduction of the three individual PAHs, which was higher than for digestion at 60 degrees C.

  • 39. Diehl, Stefan
    et al.
    Zambrano, Jesús
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Carlsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Steady-state Analysis and Design of Activated Sludge Processes Including Compressive Settling2015In: Proc. 9th IWA Symposium on Systems Analysis and Integrated Assessment, 2015Conference paper (Other academic)
  • 40. Diehl, Stefan
    et al.
    Zambrano, Jesús
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Carlsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Steady-state analysis of activated sludge processes with a settler model including sludge compression2016In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 88, 104-116 p.Article in journal (Refereed)
    Abstract [en]

    A reduced model of a completely stirred-tank bioreactor coupled to a settling tank with recycle is analyzed in its steady states. In the reactor, the concentrations of one dominant particulate biomass and one soluble substrate component are modelled. While the biomass decay rate is assumed to be constant, growth kinetics can depend on both substrate and biomass concentrations, and optionally model substrate inhibition. Compressive and hindered settling phenomena are included using the Bürger-Diehl settler model, which consists of a partial differential equation. Steady-state solutions of this partial differential equation are obtained from an ordinary differential equation, making steady-state analysis of the entire plant difficult. A key result showing that the ordinary differential equation can be replaced with an approximate algebraic equation simplifies model analysis. This algebraic equation takes the location of the sludge-blanket during normal operation into account, allowing for the limiting flux capacity caused by compressive settling to easily be included in the steady-state mass balance equations for the entire plant system. This novel approach grants the possibility of more realistic solutions than other previously published reduced models, comprised of yet simpler settler assumptions. The steady-state concentrations, solids residence time, and the wastage flow ratio are functions of the recycle ratio. Solutions are shown for various growth kinetics; with different values of biomass decay rate, influent volumetric flow, and substrate concentration.

  • 41. Diehl, Stefan
    et al.
    Zambrano, Jesús
    Carlsson, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Steady-state analyses of activated sludge processes with plug-flow reactor2017In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 5, no 1, 795-809 p.Article in journal (Refereed)
  • 42.
    Dremé, Maria
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    EXERGIOPTIMERING PÅ KÄPPALAVERKET2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Käppala wastewater treatment plant (WWTP) is situated on the island of Lidingö east of Stockholm. In 2009 the load to the plant was approximately 540 000 person equivalents (p.e). The Käppala WWTP is owned by the Käppala Association, which is a union of eleven municipalities in the northern and eastern parts of the Stockholm area, treat the waste water from those municipalities.

    Käppalaverket is aiming to continuously optimize its activities, regarding both environmental and economical aspects. An important factor in the optimization of Käppalaverket is to create a sewage treatment process that is as energy and resource efficient as possible. This implies a good utilization of the resources that reach the plant through the waste water in the form of organic material and heat, but also to exploit the products that are formed (e.g. sludge and biogas).

    One way of measuring and evaluating this resource efficiency is to establish an exergy balance over the system by converting all energy flows in and out of the system into their corresponding exergy values. Svenskt Vatten (The Swedish Water & Waste Water Association) is in the process of developing a benchmarking tool where these values are used to calculate indices [1]. These indices can then be used to make comparisons between the exergy efficiency of the Käppala WWTP and other plants.

    Within the scope of a master’s thesis in Chemical Engineering at the Royal Institute of Technology (KTH) in Stockholm, the above mentioned exergy balance and exergy indices have been calculated for both years 2009 and 2010. The results of these calculations for 2009 show that Käppalaverket reached a high degree of treatment, but its exergy efficiency was low compared to other waste water treatment plants. The main reason for this was that the Käppala WWTP until June 2010 used its biogas for production of district heating, which resulted in poor exergy indices. The results for 2010, when the plant started producing vehicle fuel, show that the Käppala WWTP has now improved its exergy efficiency, and consequently its exergy indices are also better.

    As a further part of the project, an exergy analysis of the current sludge dewatering process at the Käppala WWTP was performed. The factors taken into consideration were the demand of electricity and chemicals, decrease of sludge transports from the plant, and the use of sludge as a fertilizer. The exergy efficiency of this process was then compared to the exergy efficiency of two other options for dewatering of sludge. The conclusion that could be drawn from this comparison was that the current dewatering process is very exergy efficient, much thanks to the fact that the sludge is hygienized without the energy-intensive thermophilic digestion.

  • 43.
    Elleby, Rasmus
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Användning av anlagd våtmark för efterpolering av rökgaskondensat: en studie vid Brista kraftvärmeverk i Sigtuna2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    At the Brista combined heat and power plant in Sigtuna, wood chips and municipal and industrial waste are incinerated to generate and export electricity and distric heating. When the flue gas is cooled as a part of recycling its energy for distric heating, condensate is formed. Directly after production, the flue gas condensate has a temperature of approximately 30°C and contains relatively high levels of ammonia and certain heavy metals. After treatment inside the plant, the condensate is post-treated in a newly constructed wetland. The main aim of the study was to investigate the nitrogen removal in the wetland but also if current guideline values for effluents established by the environmental court are fulfilled in regard to levels of total and ammonia nitrogen as well as As and heavy metals Cd, Co, Cr, Cu, Hg , Ni, Pb, Tl  and Zn. The study also aimed to measure the wetland area, volume and retention time, investigate differences in water flow between the inlet and outlet as well as study the effect of water temperature on nitrogen removal.

    Water samples were taken weekly for nine weeks in October and November 2014 in the inlet and outlet of the wetland. The samples were analysed for nitrate, nitrite and ammonium ions using ion chromatography. Data from Fortum, the company that runs the heat and power plant, were also used to study levels of nitrogen and metals in the wetland. An optical leveling instrument was used to calculate the wetland volume and GPS was used to calculate its length and area. Measurements of water temperature in the outlet of the wetland were conducted using a logger during a two-month period. Water flow out of the wetland was calculated using water level data from a pump well connected to the outlet.

    The results showed that the levels of the studied compounds in samples collected in this study and by Fortum were all below guideline values. The levels were also low in the flue gas condensate leaving the combined heat and power plant, indicating that the treatment inside the plant is working well. The area of the wetland was measured to 2300 m2 and the volume 940 m3. The calculated water flow out of the wetland was at an average approximately 100 m3/day higher than the inflow, but an error in the calculation model is a possible cause of the difference.

    At low air temperatures, the wetland showed a capacity of cooling significantly higher temperatures of the flue gas condensate than what is usually released from the plant. Because of this, Fortum is recommended to investigate the possibility of reducing the cooling of the flue gas condensate and thus enabling a higher efficiency of temperature dependent treatment processes in the wetland such as nitrogen removal.

  • 44.
    Englund, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Sveriges lantbruksuniversitet .
    Evaluation of the Removal Efficiency of Perfluoroalkyl Substances in Drinking Water2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Per- and polyfluoroalkyl substances (PFASs) are chemicals that have been used for over 50 years. They are both hydrophobic and hydrophilic, which make them useful in a wide range of products, both in the domestic and industrial market. Recently, the global attention on PFASs has increased due to their possible harmful health effects on humans. Furthermore, PFASs have been detected in drinking water sources all over the world. Conventional treatment processes in drinking water treatment plants (DWTPs) are not able to remove PFASs. Therefore, more research is required to find efficient removal techniques for these compounds.

    The aim of this study was to investigate the removal efficiency of PFASs using two different adsorption techniques, anion exchange (AE) with the resin Purolite A-600, and granular activated carbon (GAC) of type Filtrasorb®400. The experiments were performed in laboratory batch-scale, at Swedish University of Agriculture (SLU), and column tests in pilot-scale, at Bäcklösa DWTP in Uppsala.

    The PFASs showed a high sorption potential to AE and GAC. However, the removal efficiency differed depending on the perfluorocarbon chain length, functional group, and concentration level. For the AE, in average 92 % of the PFASs were removed in the end of the batch experiments while the average removal efficiency in the column experiment was 86 %. In the batch experiments treated with GAC on average 55 % of the PFASs were removed in the end of the experiments while the column experiment had the average removal efficiency of 86 %. There was an increase in the removal efficiency with increasing perfluorocarbon chain length in the column experiments. However, in the batch experiments, the adsorption of PFASs decreased with an increasing chain length, except for the highest PFAS concentration level (5000 ng L-1) treated with AE and the lowest PFAS concentration level (200 ng L-1) treated with GAC. In the column experiments, the perfluoroalkane sulfonates (PFSAs) were slightly better removed than perfluoroalkyl carboxylates (PFCAs) with an average removal efficiency of 97 % for AE and 91 % for GAC compared to 67 % and 82 % for AE and GAC, respectively. In the batch experiments, there was no clear trend between the removal efficiency and functional group. Overall, the pilot-scale experiments removed the PFASs relatively well even after 42 days (on average, 86 % for both AE and GAC). The lowest removal capacity in the column experiments was seen for the shorter chained PFSAs (in average 46 % for ≤C6 PFCAs using AE and 75 % for ≤C7 PFCAs using GAC). More efficient treatment techniques are needed to minimise the PFAS concentrations in drinking water and the potential human.

  • 45. Engqvist, A.
    et al.
    Stenström, Petter
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Pierce, Kena
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Modelling the effects of a pumping program for increasing water circulation in a semi-enclosed bay in the Stockholm archipelago2006In: Proceedings of the International Conference on Estuarine and Coastal Modeling, 2006, 253-269 p.Conference paper (Refereed)
    Abstract [en]

    Brunnsviken in the inner Stockholm archipelago, close to the City of Stockholm and popular for recreational activities, is a semi-enclosed bay with a very narrow passage to the adjacent archipelago and consequently has a limited water exchange. Various attempts have been made over the past three decades to improve the water quality in the bay. Since 1986, the drinking water authorities of Stockholm withdraw bottom water by pumping it from one of the deep basins of the bay through a pipe to be eventually discharged into the nearest embayment of the archipelago. There are, however, some questions regarding the cost-benefit aspect of this strategy. In particular, it is unclear if the location and the rate of pumping are well chosen in order to increase the ventilation of the bay at large. In addition, it should be possible to eventually optimize the pumping schedule, so that these energy-demanding and thus costly efforts are concentrated to times when they act in concert with natural forcing to increase water exchange. To help improve the pumping program, a modelling project was started in spring 2004. First, a one-dimensional (1-D) layer model that resolves the bay into one basin with multiple-layer stratification was attempted. Second, a three-dimensional (3-D) model with the capacity to be run under non-hydrostatic assumptions was set up at high resolution to study a number of scenarios. Both models were forced by wind, river discharge, surface temperature and the exchange driven by density fluctuations across the boundary to the adjacent archipelago. In the 3-D model, the pumping is included as a virtual divergence of the flow at the location of the pipe. The main results are that the 1-D model performs considerably better than the 3-D model in simulating the measured salinity profiles, even though it does not resolve the basin in the horizontal direction. The poor performance of the 3-D model with regard to salinity is however mainly due to boundary problems: too little inflow of saline water through the narrow and shallow entrance channel, and underestimation of the freshwater supply. The dynamics of the thermocline is better captured by the 3-D model but can certainly also be improved.

  • 46.
    Engström, Emma
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Management and Assessment.
    Transport and Fate of Escherichia coli in Unsaturated Porous Media2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The unsaturated zone could provide an effective barrier against pathogenic microbes entering the groundwater. Knowledge relating to microbial fate in this zone is therefore important for increased understanding of groundwater vulnerability. This thesis examines the published literature that is related to the transport, retention and survival processes that apply to the fecal indicator bacterium Escherichia coli in unsaturated porous media. The main focus concerns the research findings under steady-state flow in homogeneous filter media, and under unfavorable attachment conditions, which are the most common in the natural environment. Experimental results in the literature for the pore-, column- and field-scale are examined and compared to commonly applied theories and modeling approaches. An analysis of the main factors that influence attenuation and biofilm formation is provided. Further, the findings are illustrated in a model of an unplanted, vertical flow constructed wetland. The results indicate that retention at the solid-air-water interface is a major attenuation process. In addition, they suggest that the flow velocity (as dependent on the grain size and the saturation) is a key influencing factor. However, it has not yet been established how the research findings relating to the main processes and influencing factors can be incorporated into predictive models; in the literature, a multitude of models have been proposed and alternative theories could describe the same observation. In this study, the transport and fate of Escherichia coli in different sand filters is, therefore, modeled using various literature models - derived under similar experimental conditions - in order to assess the possibility to compare and generalize the equations, evaluate their implications considering the different saturation settings and filter depths, and to define the spectra of the reduction efficiencies. It is discovered that the bacterial attenuation behaviors vary largely. This calls for clarification regarding the underlying processes. Future research is also recommended to include the ef-fects of structured filter media and sudden changes in the flow rate.

  • 47.
    Engström, Emma
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Management and Assessment.
    Balfors, Berit
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Management and Assessment.
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Management and Assessment.
    Modeling bacterial transport and removal in a constructed wetland system2010In: Proceedings of the COMSOL Conference, 2010, Paris, 2010Conference paper (Refereed)
  • 48.
    Engström, Emma
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Management and Assessment.
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Management and Assessment.
    Balfors, Berit
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Management and Assessment.
    Predicting the transport and fate of Escherichia coli in unsaturated sand filters2011In: Journal of Contaminant Hydrology, ISSN 0169-7722, E-ISSN 1873-6009Article in journal (Other academic)
  • 49.
    Engström, Emma
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Management and Assessment.
    Thunvik, Roger
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Management and Assessment.
    Kulabako, Robinah
    Department of Civil Engineering, Makerere University, Kampala, Uganda.
    Balfors, Berit
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Management and Assessment.
    Escherichia coli transport and fate in unsaturated porous media: a literature review of experimental findings and theories relating to processes, models and influencing factors2011In: Critical reviews in environmental science and technology, ISSN 1064-3389, E-ISSN 1547-6537Article in journal (Other academic)
  • 50.
    Erlingsson, Bo-Anders
    Kristianstad University, School of Education and Environment.
    Råstorps avloppsnät: Förslag till ombyggnad av avloppssystemet i Råstorp2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Rapporten handlar om ett vakuumsystem i Råstorp som är i behov av att bytas ut inom de närmaste åren.Med hjälp av personalen på Va-verket i Markaryd har jag fått en bild av hur det fungerar idag. Det finns en del problem med service och reservdelar, men framförallt så går det inte att lita på att systemet fungerar.Jag har mätt ut befintliga höjder, både markhöjd och vattengång vid de brunnar som finns. Av detta har jag sedan, bland annat, gjort beräkningar på självfallssystem. Därefter har jag kommit fram till att ett kombinerat system, självfallsledningar och tryckavloppssystem skulle kunna var en lösning.

1234 1 - 50 of 158
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