Change search
Refine search result
456789 301 - 350 of 421
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 301.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Integrated sustainability assessment of forest bioenergy options in multiple-use landscapes2013Conference paper (Other academic)
  • 302.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Non-linear spatial optimization for incorporating spatial dimensions of ecosystem services in assessment of forest bioenergy options2016Conference paper (Other academic)
  • 303.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Sustainability assessment of forest bioenergy options in multiple-use landscapes2013Conference paper (Other academic)
  • 304.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Balfors, Berit
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    A GIS-based approach to assessment of impacts on biodiversity and ecosystem services2013Conference paper (Refereed)
  • 305.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Brown, Nils
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Environmental Strategies Research (fms).
    Energy models from a strategic environmental assessment perspective in an EU context: What is missing concerning renewables?2014In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 33, p. 353-362Article in journal (Refereed)
    Abstract [en]

    Climate change and security of energy supply are main sustainability issues today and an energy systems shift towards renewable energy sources is therefore urgent. However, unless environmental impacts of such a shift are carefully taken into account, imposed resource and land use changes may counteract other sustainability goals, such as preserving biodiversity and ecosystem services. Strategic Environmental Assessment (SEA) provides a comprehensive framework for assessment of policies and plans where a full range of environmental issues are addressed. The aim of this article was to find possibilities for comprehensive sustainability assessment among published energy-environment models and the linking of renewable energy analysis to landscape and biodiversity issues through land use concerns. Based on the review of relevant energy, environmental and linking models, a survey on publications and a case study on the EU Energy Roadmap 2050, the results show that existing energy models and research have low concerns on land use, landscapes and biodiversity. Consequently, it would be difficult to provide comprehensive decision support by using only these tools. However, suitable energy models, ecological assessment models and multi-criteria approaches exist with great potential for inter-linking. The development of energy models could thus have new orientations, connecting them to involve renewable energy options with land use, landscape and biodiversity concerns, which could be advanced into powerful SEA tools for integrated policy assessment. This will enable the development of more comprehensive decision support tools for assessing future energy scenarios, integrating main policy concerns when assessing renewable energy options.

  • 306.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Nordström, Eva-Maria
    Böttcher, Hannes
    Sallnäs, Ola
    Sustainability assessment of forest bioenergy options in multiple-use landscapes2015Conference paper (Other academic)
  • 307.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Sallnäs, Ola
    Nordström, Eva-Maria
    Böttcher, Hannes
    Trade-offs and synergies among ecosystem services and biodiversity under different forest management scenarios: Case study of a forest landscape in southern Sweden2015In: 9th International Association for Landscape Ecology (IALE) World Congress, 2015Conference paper (Refereed)
  • 308.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    Sallnäs, Ola
    Trubins, Renats
    Nordström, Eva-Maria
    Böttcher, Hannes
    Ecological network assessment of forest bioenergy options using the landscape simulator LandSim: a case study of Kronoberg, southern SwedenManuscript (preprint) (Other academic)
    Abstract [en]

    The need to adapt to climate change as well as to secure the supply of energy has led to a shift in energy consumption from fossil fuel to renewables. In this context, forest biomass is a resource that is increasingly utilised for bioenergy purposes in Sweden, which along with the extraction of industrial wood may conflict with other sustainability goals such as those related to biodiversity conservation. In order to balance between main sustainability objectives, land zoning policies and related management regimes has been proposed, differentiating between the main management categories protected areas, multi-purpose forestry and intensive forestry. The aim of this project was to develop methods and tools for integrated sustainability assessment of forest biomass extraction, in particular from bioenergy and biodiversity perspectives.

    For this purpose, the landscape simulator LandSim was developed and applied in a case study in Kronoberg County in southern Sweden. Forest growth and management was simulated in 5-year time steps for the period 2010-2110. The management followed two land zoning scenarios, one applying even-aged forestry on all forest land except for protected areas (EAF-tot), and one was applying continuous cover forestry on parts of the forest land, combined with protected areas and a shorter rotation time on the other parts (CCF-int). The outcome of the simulations was raster data on tree species, volume and age for each time step and scenario. From the outcome, harvested volumes and bioenergy feedstock yields were derived. The same outcome was used for an ecological network assessment, using the indicator Equivalent Connected Area (ECA) for two model species tied to mature and old coniferous and southern broadleaved forest, respectively.

    The results showed that the EAF-tot scenario implied higher yields of biomass feedstock for bioenergy than the CCF-int scenario, while the CCF-int scenario displayed more even yields over the years. By contrast, the CCF-int scenario performed substantially better than the EAF-tot scenario when it came to the ECA indicators. However, the CCF-int scenario involved a range of assumptions mirroring major uncertainties on habitat suitability, which yielded separate results and thus will need further exploration. Moreover, in order to support the model species and related biodiversity components, the forest management would need to allow larger areas to become suitable habitat, as well as to plan for habitat amount and connectivity on landscape scale in order to not only increase habitat size but also ECAs. Conclusively, the modelling framework linking the landscape simulator with the ecological network model could be used for integrated sustainability assessment of bioenergy options, integrating main policy concerns when assessing renewable energy options.

  • 309.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Sallnäs, Ola
    Trubins, Renats
    Nordström, Eva-Maria
    Böttcher, Hannes
    Habitat network assessment of forest bioenergy options using the landscape simulator LandSim: A case study of Kronoberg, southern Sweden2017In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 345, p. 99-112Article in journal (Refereed)
    Abstract [en]

    Forest biomass is a renewable resource that is increasingly utilised for bioenergy purposes in Sweden, which along with the extraction of industrial wood may conflict with biodiversity conservation. The aim of this paper is to present a method for integrated sustainability assessment of forest biomass extraction, particularly from bioenergy and biodiversity perspectives. The landscape simulator LandSim was developed and linked with models for the assessment of biomass yields and habitat networks representing prioritised biodiversity components. It was applied in a case study in Kronoberg County in southern Sweden. Forest growth and management were simulated for the period 2010-2110, following two land zoning scenarios, one applying even-aged forest management on all forest land except for protected areas (EAF-tot), and one applying continuous cover forest management on parts of the forest land, combined with protected areas and an intensified even-aged management on the other parts (CCF-int). The EAF-tot scenario implied higher yields of biomass feedstock for bioenergy, the CCF-int scenario only giving 66% of that yield, while the CCF-int scenario performed substantially better when it came to the habitat network indicators, if habitat suitability was ensured. Conclusively, the case study confirmed that the modelling framework of the LEcA tool, linking the landscape simulator LandSim with the biomass yield assessment and the habitat network model can be used for integrating main policy concerns when assessing renewable energy options.

  • 310.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Trubins, Renats
    SLU.
    Sallnäs, Ola
    SLU.
    The LEcA Tool for energy-environment systems analysis2016Conference paper (Other academic)
  • 311.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Trubins, Renats
    Swedish University of Agricultural Sciences.
    Sallnäs, Ola
    Swedish University of Agricultural Sciences.
    Mizgeris, Gintautas
    Kulbokas, Gintaras
    Galinis, Arvydas
    Lekavicius, Vidas
    The Landscape simulation and Ecological Assessment (LEcA) tool: Linking with the energy model MESSAGE2017Conference paper (Refereed)
  • 312.
    Pang, Xi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Nordström, Eva-Maria
    SLU Umeå.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Böttcher, Hannes
    International Institute for Applied Systems Analysis (IIASA), Laxenburg.
    Sallnäs, Ola
    SLU Alnarp.
    Trade-offs and synergies among ecosystem services and biodiversity under different forest management scenarios: A case study of a forest landscape in southern Sweden2013Report (Refereed)
  • 313. Patel, Khageshwar Singh
    et al.
    Sahu, Bharat Lal
    Dahariya, Nohar Singh
    Bhatia, Amarpreet
    Patel, Raj Kishore
    Matini, Laurent
    Sracek, Ondra
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Groundwater arsenic and fluoride in Rajnandgaon District, Chhattisgarh, northeastern India2017In: Applied water science, ISSN 2190-5487, E-ISSN 2190-5495, Vol. 7, no 4, p. 1817-1826Article in journal (Refereed)
    Abstract [en]

    The groundwater of Ambagarh Chouki, Rajnandgaon, India, shows elevated levels of As and F-, frequently above the WHO guidelines. In this work, the concentrations of As, F-, Na+, Mg2+, Ca2+, Cl-, SO42-, HCO3-, Fe, dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in the groundwater of Ambagarh Chouki are described. The sources of dissolved components in the groundwater are investigated using the cluster and factor analysis. Five factors have been identified and linked to processes responsible for the formation of groundwater chemistry. High concentrations of dissolved As seems to be linked to high concentrations of DOC, suggesting reductive dissolution of ferric oxyhydroxides as arsenic mobilization process. Fluoride is found in shallow depth water, presumably as a consequence of evaporation of water and removal of Ca2+ by precipitation of carbonates.

  • 314. Persson, F.
    et al.
    Sultana, Razia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Suarez, M.
    Hermansson, M.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Wilén, B. -M
    Structure and composition of biofilm communities in a moving bed biofilm reactor for nitritation-anammox at low temperatures2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 154, p. 267-273Article in journal (Refereed)
    Abstract [en]

    It is a challenge to apply anaerobic ammonium oxidation (anammox) for nitrogen removal from wastewater at low temperatures. Maintenance of anammox- and aerobic ammonia oxidizing bacteria (AOB) and suppression of nitrite oxidizing bacteria (NOB) are key issues. In this work, a nitritation-anammox moving bed biofilm pilot reactor was operated at 19-10°C for 300d. Nitrogen removal was decreasing, but stable, at 19-13°C. At 10°C removal became unstable. Quantitative PCR, fluorescence in situ hybridization and gene sequencing showed that no major microbial community changes were observed with decreased temperature. Anammox bacteria dominated the biofilm (0.9-1.2×1014 16S rRNA copies m-2). Most anammox bacteria were similar to Brocadia sp. 40, but another smaller Brocadia population was present near the biofilm-water interface, where also the AOB community (Nitrosomonas) was concentrated in thin layers (1.8-5.3×1012 amoA copies m-2). NOB (Nitrobacter, Nitrospira) were always present at low concentrations (<1.3×1011 16S rRNA copies m-2).

  • 315.
    Persson, Joakim
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Andersson, Niklas
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Modeling groundwater flow and PFOS transport.: A case study at the old fire drill site of Bromma Stockholm Airport.2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    At Bromma Stockholm Airport, fire drills have previously been performed at a location outside the current airport confinements. Fire drills were performed with extinguisher foams containing toxic perfluorooctanesulfonic acid (PFOS), which have polluted the site. Harmful effects of PFOS include but are not limited to damages to the endocrine system. The contaminant is relatively soluble and can be transported by water. The aim of this thesis was to model groundwater flows and PFOS transport in the area. In order to build the model, data was gathered from databases, literature studies and field investigations. The field investigations included geophysical measurements. The model was built in the software Visual MODFLOW Classic. It was used to increase knowledge of hydrogeological conditions in the area, predict the fate of PFOS leaching from the site and suggest preventative measures for preventing the spread. The model results showed that the contaminant is transported towards the current airport area by means of groundwater at a slow rate and with low concentrations. Additionally, high concentrations of PFOS will remain in soil and groundwater at the study area for several hundreds of years, according to model results. Preventative measures should therefore be focused on minimizing risks to frequent visitors to the site, which is currently used as a golf course.

  • 316.
    Petersson, Mona
    et al.
    Södertörn University College.
    Hammer, Monica
    Södertörn University College.
    Mörtberg, Ulla
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Trade-offs and ecosystem services in landscape planning and governance: A case study of the implementation of the EU Water Framework Directive2013Conference paper (Refereed)
  • 317.
    Pham Van, Quang
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. An Giang University.
    Soil Degradation of Raised-beds on Orchards in the Mekong Delta Field and Laboratory Methods2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Soil degradation is a complex process which may occur anywhere and at any time. It directly affects the physical, chemical and biological processes within the soil profile. Soil degradation can either be as a result of natural hazards or due to manmade actions, such as mismanagement on cropping patterns, soil preparation and cultivation practices. Regardless of how it is caused, soil degradation has strong negative effects on plant and soil productivity. Soil degradation can accelerate a series of processes such as erosion, compaction, loss of organic matter, loss of whole soil biota, surface sealing and contamination. This thesis presents the assessment of soil properties to improve our understanding of soil degradation on raised-bed orchards in the Vietnamese Mekong delta (MD). Measurements were made on 10 citrus plantations which had been established during a range of years from 1970 to 1998 at Hau Giang province. Soil sampling was made in the dry season of 2010 at two soil depths for each raised-bed to determine soil chemical and physical properties. The soil penetration resistance (PR) was periodically measured once a week together with soil sampling for moisture measurements during a period of 5 months. Analysis indicated the pH value of the soil was tending to decrease, nutrient imbalance and deficiency was developing, and the soil structure was deteriorating during the age since the raised-beds were originally constructed. Preventive and restorative measures need to be considered for restoring and retaining the quality of the soil and the ground water. These measures should consist of (1) neutralizing of excess acidity, (2) balancing of nutrients, (3) maintaining of soil organic matter, and (4) application of appropriate irrigation schedules.

  • 318. Pramanik, B. K.
    et al.
    Kajol, Annaduzzaman
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Suja, F.
    Md Zain, S.
    Effect of biological and coagulation pre-treatments to control organic and biofouling potential components of ultrafiltration membrane in the treatment of lake water2016In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Biological aerated filter (BAF), sand filtration (SF), alum and Moringa oleifera coagulation were investigated as a pre-treatment for reducing the organic and biofouling potential component of an ultrafiltration (UF) membrane in the treatment of lake water. The carbohydrate content was mainly responsible for reversible fouling of the UF membrane compared to protein or dissolved organic carbon (DOC) content. All pre-treatment could effectively reduce these contents and led to improve the UF filterability. Both BAF and SF markedly led to improvement in flux than coagulation processes, and alum gave greater flux than M. oleifera. This was attributed to the effective removal and/or breakdown of high molecular weight (MW) organics by biofilters. BAF led to greater improvement in flux than SF, due to greater breakdown of high MW organics, and this was also confirmed by the attenuated total reflection-Fourier transform infrared spectroscopy analysis. Coagulation processes were ineffective in removing biofouling potential components, whereas both biofilters were very effective as shown by the reduction of low MW organics, biodegradable dissolved organic carbon and assimilable organic carbon contents. This study demonstrated the potential of biological pre-treatments for reducing organic and biofouling potential component and thus improving flux for the UF of lake water treatment.

  • 319.
    Ramos Ramos, Oswaldo Eduardo
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Universidad Mayor de San Andrés, Instituto de Investigaciones Químicas.
    Geochemistry of Trace Elements in the Bolivian Altiplano: Effects of natural processes and anthropogenic activities2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The occurrence of As in groundwater in Argentina was known since 1917; however, the occurrence, distribution and mobilization of As and other trace elements (TEs) in groundwater in the Bolivian Altiplano are still quite unknown. An investigation applying a geochemical approach was conducted in the Poopó Basin and Lake Titicaca to understand processes of TEs in different systems such as water, soils, crops and sediments in mining areas.

    In Poopó Basin,As, Cd and Mn concentrations exceed World Health Organization (WHO) guidelines and Bolivian regulations for drinking water in different places around the basin, but Cu, Ni, Pb and Zn do not.

    In soils, the sequential extraction methods extracted up to 12% (fractions 1 and 2), which represent < 3.1 mg/kg of the total As content, as potentially mobilized fractions, that could be transferred to crops and/or dissolved in hydrologic system. The large pool of As can be attached due to amorphous and crystalline Fe oxide surfaces (fractions 3, 4, and 5) present in the soils.

    Furthermore, the concentrations of As, Cd and Pb in the edible part of the crops revealed that the concentrations of As and Cd do not exceed the international regulation (FAO, WHO, EC, Chilean) (0.50 mg/kgfw for As and 0.10 mg/kgfw for Cd), while Pb exceeds the international regulations for beans and potatoes (for beans 0.20 mg/kgfw and for potato 0.10 mg/kgfw).

    In the Lake Titicaca, principal component analysis (PCA) of TEs in sediments suggests that the Co-Ni-Cd association can be attributed to natural sources such as rock mineralization, while Cu-Fe-Mn come from effluents and mining activities, whereas Pb-Zn are mainly related to mining activities. The Risk Assessment Code (RAC) indicate “moderately to high risk” for mobilization of Cd, Co, Mn, Ni, Pb and Zn, while Cu and Fe indicate “low to moderate risk” for remobilization in the water column.

  • 320.
    Ramos Ramos, Oswaldo Eduardo
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Rötting, Tobias S.
    French, Megan
    Stacek, Ondra
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Quintanilla, Jorge
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Geochemical processes controlling mobilization of arsenic and trace elements in shallow aquifers and surface waters in the Antequera and Poopó mining regions, Bolivian Altiplano2014In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 518, no C, p. 421-433Article in journal (Refereed)
    Abstract [en]

    A geochemical approach was applied to understand the factors controlling the mobilization of As and trace elements (TEs) in mining areas of the Poopó and Antequera River sub-basins on the Bolivian Altiplano. A total of 52 samples (surface, groundwater and geothermal water) were collected during the rainy season (2009). Arsenic, Cd and Mn concentrations exceed World Health Organization (WHO) drinking water guidelines and Bolivian regulations for drinking water in 28 groundwater samples, but Cu, Ni, Pb and Zn do not. Arsenic, Cd, Mn, Pb and Zn concentrations exceed World Health Organization guidelines for drinking water and Bolivian regulations Class A standard for discharge to water bodies in 20 surface water samples, whereas levels of Cu do not, and Ni and Fe rarely exceed regulation and guideline values. Factor analysis was applied to 18 hydrochemical parameters of 52 samples. Five factors for groundwater (plagioclase weathering, dissolution of gypsum and halite, TEs mobilization at acidic pH, sulfide oxidation, and release of As) account for 86.5% of the total variance for Antequera and 83.9% for Poopó sub-basins. Four factors for surface water data (weathering and mobilization of TEs influenced by pH, dissolution of evaporate salts, neutralization of acid mine drainage, and As release due to dissolution of Mn and Fe oxides) account for 91% of the total variance in Antequera and 96% in Poopó sub-basins. The As and TEs mobilized in these regions could affect the local water sources, which is a prevalent concern with respect to water resource management in this semi-arid Altiplano region. Presence of both natural and anthropogenic sources of contamination requires careful monitoring of water quality.

  • 321.
    Ramos Ramos, Oswaldo Eduardo
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Rötting, Tobias S.
    French, Megan
    Stacek, Ondra
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Quintanilla, Jorge
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Hydrochemical characteristics of groundwater and surface water in the mining region of Antequera and Poopó, Eastern Cordillera, Bolivian AltiplanoManuscript (preprint) (Other academic)
  • 322.
    Ramos Ramos, Oswaldo Eduardo
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Rötting, Tobias S.
    Orsag, Vladimir
    Chambi, Lourdes
    Stacek, Ondra
    Quintanilla, Jorge
    Bundschuh, Jochen
    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.
    Total and available trace elements concentrations in soils and evaluation of uptake by crops in the mining area of the Bolivian AltiplanoManuscript (preprint) (Other academic)
  • 323. Rappe George, M. O.
    et al.
    Hansson, L. J.
    Ring, E.
    Jansson, Per Erik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Gärdenäs, A. I.
    Nitrogen leaching following clear-cutting and soil scarification at a Scots pine site – A modelling study of a fertilization experiment2017In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 385, p. 281-294Article in journal (Refereed)
    Abstract [en]

    Boreal forest stands fertilized with nitrogen (N) might be susceptible to elevated N leaching following clear-cutting, with consequences for water quality and soil acidification. Here, we studied a forest fertilization experiment with N, 165 Hagfors, in Sweden during the first six years (2006–2011) following clear-cutting. The N fertilization treatments were 0 kg ha−1 (0 N) and 450 kg ha−1 of N (450 N), supplied during 1981–1992 to a Scots pine (Pinus sylvestris L.) stand: the stand was harvested in March 2006. Following clear-cutting, disc trenching was performed and furrows (F), ridges (R) and areas in-between two furrows (IB) were created. We calculated the N leaching fluxes and ecosystem N budget during 2006–2011 as affected by previous N fertilization, disc trenching and interactions thereof, at Hagfors by the use of a process-based biogeophysical ecosystem model (CoupModel). The model was calibrated against measurements of soil water and temperature dynamics and previously reported measurements of N in soil solution, soil organic matter and vegetation biomass. Criteria for acceptance of model estimates were based on the range enclosed by the 95% confidence intervals of the mean of the field data used in calibration sampled at low frequency (1–2 occasions) and a combination of the mean error and the coefficient of the determination for variables sampled at a higher frequency (28–1921 occasions). The accepted model estimates of the mean annual leaching rates of N were 3.1 (range 1.4–22.7) and 2.4 (range 0.8–7.0) kg ha−1 of N year−1 in the treatments 0 N and 450 N, respectively, without disc trenching. Disc trenching increased N leaching during the regeneration phase, more so in the 450 N treatment (mean 6.1, range 1.9–16.7 kg ha−1 of N year−1) than in the 0 N treatment (mean 4.6, range 1.9–12.9 kg ha−1 of N year−1). Overall, differences in the posterior model parameter estimates between N treatments and disc trenched treatments F, R and IB were related to the soil physical component: the differences resulted in enhanced drainage in the disc trenched treatments. We conclude that vegetation biomass N accumulation controlled soil water N leaching, and disc trenching increased N leaching from the previously N fertilized plots at Hagfors by its effects on water drainage flow and vegetation N uptake. This finding warrants more research since N fertilization followed by soil scarification in boreal forests is a practice which may increase in the future.

  • 324. Rasmus, S.
    et al.
    Gustafsson, David
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Koivusalo, H.
    Laurén, A.
    Grelle, A.
    Kauppinen, O. -K
    Lagnvall, O.
    Lindroth, A.
    Rasmus, K.
    Svensson, M.
    Weslien, P.
    Estimation of winter leaf area index and sky view fraction for snow modelling in boreal coniferous forests: Consequences on snow mass and energy balance2013In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 27, no 20, p. 2876-2891Article in journal (Refereed)
    Abstract [en]

    Leaf area index (LAI) and canopy coverage are important parameters when modelling snow process in coniferous forests, controlling interception and transmitting radiation. Estimates of LAI and sky view factor show large variability depending on the estimation method used, and it is not clear how this is reflected in the calculated snow processes beneath the canopy. In this study, the winter LAI and sky view fraction were estimated using different optical and biomass-based approximations in several boreal coniferous forest stands in Fennoscandia with different stand density, age and site latitude. The biomass-based estimate of LAI derived from forest inventory data was close to the values derived from the optical measurements at most sites, suggesting that forest inventory data can be used as input to snow hydrological modelling. Heterogeneity of tree species and site fertility, as well as edge effects between different forest compartments, caused differences in the LAI estimates at some sites. A snow energy and mass balance model (SNOWPACK) was applied to detect how the differences in the estimated values of the winter LAI and sky view fraction were reflected in simulated snow processes. In the simulations, an increase in LAI and a decrease in sky view fraction changed the snow surface energy balance by decreasing shortwave radiation input and increasing longwave radiation input. Changes in LAI and sky view fraction affected directly snow accumulation through altered throughfall fraction and indirectly snowmelt through the changed surface energy balance. Changes in LAI and sky view fraction had a greater impact on mean incoming radiation beneath the canopy than on other energy fluxes. Snowmelt was affected more than snow accumulation. The effect of canopy parameters on evaporation loss from intercepted snow was comparable with the effect of variation in governing meteorological variables such as precipitation intensity and air temperature.

  • 325. Rasmus, Sirpa
    et al.
    Gustafsson, David
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Lundell, Robin
    Saarinen, Timo
    Observations and snow model simulations of winter energy balance terms within and between different coniferous forests in southern boreal Finland2016In: Hydrology Research, ISSN 1998-9563, Vol. 47, no 1, p. 201-216Article in journal (Refereed)
    Abstract [en]

    Variation of canopy properties between different forest types is seldom taken into account in hydrological and climate models, and consideration of variation inside a forest is normally omitted. In this work, three data sets on near surface energy balance terms (incoming shortwave and longwave radiation; air and snow-soil interface temperatures) were collected in the southern boreal coniferous zone in Finland during three winters below different types of forest canopies. The aim was to evaluate the ability of a snow mass and energy balance model with a canopy module to reproduce the observed differences in below-canopy incoming radiations and snow-soil interface temperature. Clear differences were seen between pine and spruce forest sites (higher snow-soil interface temperatures and incoming shortwave fluxes, and lower incoming longwave fluxes at the pine site). Differences were also observed between the sparse and dense pine canopy locations. Canopy parameter values had a great effect on the quality of the model simulations. The combination of optically obtained leaf area index (LAI) values with a needle clumping correction and either optical or empirical sky view fraction (SVF) values as a canopy parameterization gave better correspondence to observations than the use of uncorrected effective LAI and any SVF.

  • 326.
    Rehbinder, Göran
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Can the water in two communicating wells in an unconfined aquifer oscillate?2015In: Zeitschrift für Angewandte Mathematik und Physik, ISSN 0044-2275, E-ISSN 1420-9039Article in journal (Refereed)
    Abstract [en]

    The water levels in two wells in a confined rigid aquifer with impervious bottom can exhibit damped oscillations according to a linear 1D oscillator. The oscillations can be under-damped, critical or over-damped. The present analysis shows that the water levels in two wells in an unconfined rigid aquifer with infinite lateral extent is not characterized by the classical equation of a 1D linear oscillator. Instead the motion of the water levels in the wells is characterized by a nonlinear Duffing hardening spring equation. According to Bendixson’s theorem its solution cannot oscillate.

  • 327.
    Rehbinder, Göran
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Motion of a torsion pendulum immersed in a linear viscous liquid. Influence of wave phenomena2015In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 361, p. 272-289Article in journal (Refereed)
    Abstract [en]

    A cylindrical pendulum, which is suspended by an elastic rod or wire and immersed in a viscid liquid in a cylindrical container, can undergo rotating oscillations. The propagation velocity of vorticity perturbations in the gap between the cylinder and the container is assumed to be finite. This means that the acceleration of the liquid is characterized by not only the viscosity but also by a relaxation time constant. The propagation velocity of elastic torsional waves in the rod is assumed to be finite. The equations that describe the motion of such a complicated compound system are linear and have been solved in closed form. The solution shows that there is a considerable deviation between the exact solution and the simple quasi-steady solution. The most remarkable conclusion is that the classical quasi-steady solution for very weak damping is incompatible with the general solution. Propagation of elastic waves in the suspension rod and propagation of vorticity waves in the liquid have a great influence on the rotational motion of the pendulum. The purpose of this study is to formulate the criteria that make the classical quasi-steady analysis valid. The derived solution permits also measurement of viscosity and a conceivable relaxation coefficient of the liquid as well.

  • 328.
    Rimfors, Otto
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Velichkin, Vadim
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Hydrological Modelling of Al Auja Earth Dam in the Lower Jordan Valley.2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In a populated region with very high potential evapotranspiration, where the rainwater falls only during the winter and mostly in the mountains, the need for sustainable water management and fair distribution is crucial. In the West Bank, Palestine, the main potable water source is a karst mountain aquifer system. Precipitation occurs usually in the form of rainfall in the mountainous regions during winter period and recharges the groundwater systems. The water either reaches the surface as spring water, or is extracted through pumped wells. But the scarcity of drinking water in Palestine is not due to lack of water resources or technical knowledge of water extraction but a direct consequence of Israeli policies, water management, breached water rights and the occupation of Palestinian territories. Because of such restrictions, ground water is not an option to provide more freshwater, instead it is suggested to collect rainwater runoff in reservoirs. In 2011, the first surface water dam was built in Palestine in Al Auja, just north of Ariha. It was built as an experimental project for future dams and is therefore a small earth fill dam which will be expanded to collect water also from an adjacent watershed, much larger than the current one. The purpose of this study is to determine how much bigger the reservoir needs to be to safely store the inflowing rainwater runoff in the future. This was achieved through hydrological modelling using the HEC-HMS software which is a physical based model. The data used in this study were: 25 m DEM, land use data, soil data (both from remote sense and field visit), river network map, precipitation data, location of the gauges and geological formations. Field visits and soil tests were also great contributions of insights and knowledge crucial for the project. Hourly time-series data for precipitation for the winters 2011-2012 and 2012-2013 and monthly evapotranspiration for 2010-2011 were used as input to the model. Water level data in Al Uja reservoir with 20 minutes intervals were used to evaluate the simulations. Simulations were first optimized for the current scenario to find sets of parameters that match the changes in water level in the dam reservoir. This was done both for single rainfall events as well as for the whole seasons. The parameters creating the most matching results were used in additional simulations with the adjacent watershed included. The difference in results between the simulations with the current watershed and the expanded one was used to answer how much more water the reservoir would have received during 2011-2012 and 2012-2013 if the larger watershed were included. The model results reveal that the reservoir should have been able to hold about three times as much water as today. Installation of an inflow meter is suggested for the future along with an evaluation of local climate change in precipitation and evapotranspiration.

  • 329.
    Ristinmaa, Kristoffer
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Supplemental irrigation of cereals in semi-arid areas in Ethiopia - is it worth the effort?2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With a growing world population, estimated to 9.6 billion in 2050, the world food demand is estimated to increase with 45-50 %. One way to meet the demand is to increase the areal yield from the agricultural sector, where rain-fed agriculture has the highest potential. 95 % of the agriculture in Sub-Saharan Africa is rain-fed and the same region is predicted to holds the largest share of poor people in 2015. Since 40-70 % of the rural households highly depend of on-farm sources, investments to increase the agriculture productivity target both the poverty alleviation in the region as well as the world’s food security. By a tripartite methodology, this study analyzed the use of small-scale rain water harvesting (RWH) ponds for supplemental irrigation (SI) of cereals to reduce the inter-annual variability and to increase the areal yield in semi-arid areas in Ethiopia. A physically based simulation model (CoupModel) considering the plant-soil-atmosphere system was used to study how a C4-plant responded to different irrigation scenarios with 30 years climate data (1980-2009) from six regions in Ethiopia. Moreover, two years field data with maize yield from Triple Green project’s experimental fields in Ethiopia was used to analyze the correlation between SI and yield. Finally, ten farmers that used RWH ponds for SI of cereals within Triple Green project were interviewed to find out their perception of the RWH and SI. The model results showed that irrigation almost eliminated the inter-annual variability and increased the areal yield for all the climates. SI was most efficiently used in areas with more than 900 mm precipitation/year were the two annual rain periods could be bridged to create a prolonged growth season (>180 days). The mean annual irrigation water demand was estimated to 224 mm distributed over 7 irrigation events. The field results showed a moderate but significant 10 % increase of the areal yield with SI. None of the farmers wanted to use the RWH for SI of cereals, instead they wanted to use it to water their livestock, grow cash crop seedlings and fruit trees. If the future world food demand is to be targeted, the study suggests societal investments to build infrastructure to collect, store and distribute water for irrigation.

  • 330.
    Rodriguez-Gomez, Raúl
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology. KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Moreno, Luis
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Liu, Longcheng
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    A model to describe the performance of the UASB reactor2014In: Biodegradation, ISSN 0923-9820, E-ISSN 1572-9729, Vol. 25, no 2, p. 239-251Article in journal (Refereed)
    Abstract [en]

    A dynamic model to describe the performance of the Upflow Anaerobic Sludge Blanket (UASB) reactor was developed. It includes dispersion, advection, and reaction terms, as well as the resistances through which the substrate passes before its biotransformation. The UASB reactor is viewed as several continuous stirred tank reactors connected in series. The good agreement between experimental and simulated results shows that the model is able to predict the performance of the UASB reactor (i.e. substrate concentration, biomass concentration, granule size, and height of the sludge bed).

  • 331.
    Rodríguez-Gómez, Raúl
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Closing the Loop by Combining UASB Reactor and Reactive Bed Filetr Technology for wastewater Treatment: Modelling and Practical Approaches2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A laboratory-scale upflow anaerobic sludge blanket (UASB) reactor followed by a packed bed reactor (PBR) filled with Sorbulite® in the lower part and Polonite® in the upper part was used to treat household wastewater in a 50-week experiment. A model was developed to describe the performance of the UASB reactor, including mass transfer through the film around anaerobic granules, intra-particle diffusion and bioconversion of the substrate. In a second model, a numerical expression describing the kinetics occurring in the granules was developed. It includes the resistances through which the substrate passes before biotransformation. These expressions were then linked to governing equations for the UASB reactor in order to describe degradation of the substrate, biomass growth (active and inactive), and variation in granule size over time. A third model was developed to describe the profile of the phosphorus (P) concentration throughout the PBR. In a first attempt, the analytical and numerical model was applied to data taken from previous studies in which UASB reactors were used to treat sugarcane mill wastewater and slaughterhouse wastewater. The results showed good agreement between observed and simulated results. Sensitivity analysis showed that diffusion coefficient and yield were important parameters in the UASB reactor model.The laboratory bench-scale experiment revealed that the combined UASB-PBR system efficiently treated the residential wastewater. Phosphorus, BOD7 and pathogenic bacteria all showed average removal of 99%, while total nitrogen showed a moderate reduction in the system (40%). Application of the numerical solution model to the experimental UASB reactor used resulted in good agreement between simulated and experimental values. Regarding the PBR, the model developed successfully predicted P removal. For both models, the capability and sensitivity analyses identified important parameters. A treatment system aiming to close the loop is suggested based on sequential UASB and PBR with biogas collection, nutrient recycling via sludge and filter media and elimination of pathogenic organisms.

  • 332.
    Rodríguez-Gómez, Raúl
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Phosphorus removal from UASB reactor effluent by reactive media filtrationManuscript (preprint) (Other academic)
    Abstract [en]

    The phosphorus (P) and BOD7 removal performance of an upflow packed bed reactor (PBR) filled with two reactive filter media was studied over 50 weeks. The lower one-fifth of the reactor was filled with calcium-silicate-hydrate (Sorbulite®) and the upper four-fifths with calcium-silicate (Polonite®). A laboratory-scale upflow anaerobic sludge bed reactor (UASB) delivered wastewater to the PBR. A model was developed to describe the gradient in P concentration change in the reactor, based on reaction kinetics. The reaction terms were assumed to follow the Langmuir isotherm, based on results obtained in a batch test. First, a comparison was made between experimental and simulated results. The capability of the model to forecast P removal capacity was then tested for three hypothetical cases: (i) reactor filled with Sorbulite and Polonite, (ii) reactor filled with only Sorbulite and (iii) reactor filled with only Polonite. Finally, a sensitivity analysis was performed for the main parameters in the model. The results showed that average removal of P and BOD7 from the UASB effluent was 98% and 90%, respectively. The starting pH of the dual-medium effluent was 12.2 and decreased gradually over time to 11.1. The simulation both overestimated and underestimated mean measured P removal, but was within the range of maximum and minimum measured values. The hypothetical cases revealed that most P was removed by Polonite due to calcium phosphate precipitation. The removal capacity of the two filter materials and their layer height in the reactor were the most sensitive parameters in the simulation.

  • 333.
    Rodríguez-Gómez, Raúl
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Sequential UASB and dual media packed-bed reactors for domestic wastewater treatment - Experiment and simulation2016In: Water Science and Technology, ISSN 0273-1223, Vol. 73, no 12, p. 2959-2970Article in journal (Refereed)
  • 334.
    Rundqvist, maria
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Utvärdering av avskiljning av naturligt organiskt material vid Lovö vattenverk – en pilotstudie.2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Högre halter av färg och naturligt organiskt material (NOM) i ytvattnet har på senare år blivit ett ökande problem på norra halvklotet och så även vid Lovö vattenverk. För att utvärdera nya reningsmetoder som har kapacitet att avskilja dessa föroreningar vill man använda sig av undersökningar i pilotskala. För att resultaten ska gå att överföra till vattenverket behöver man först undersöka hur den befintliga pilotanläggningens referenslinje, som ska användas som just referens vid framtida försök, förhåller sig till fullskalan. Studien kom fram till att flödet kan ställas in så att ett reningssteg i taget går med samma ytbelastning och uppehållstid i referenslinjen och i vattenverket, men ald-rig alla samtidigt på grund av skillnader i skalförhållanden mellan de olika reningsste-gen. Den mest kritiska parametern för avskiljningen av föroreningar som skapar turbi-ditet och NOM är dosen aluminiumsulfat (ALG).

    För att avskiljning av NOM mätt som bland annat UV254, TOC, DOC och SUVA krävs det i referenslinjen en överdosering av ALG på minst 15 procent för att denna ska vara lika effektiv som den i vattenverket. I den kemiska fällningen i vattenverket och i referenslinjen är det framförallt humusämnen med aromatisk struktur som tas bort. Dessa är ämnen som är mer nedbrutna och äldre i sin karaktär. Det är alltså samma fraktioner av NOM som avskiljs i de bägge processerna. Skillnaden i avskilj-ning mellan dem ligger i att det under studien avskildes kvantitativt mer NOM av äldre mer nedbrutet, humöst material i referenslinjen än i vattenverket. Detta beror på att det i referenslinjen doserades mer fällningskemikalie än i vattenverket.

  • 335.
    Rutanen, Linda
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Yt- och grundvattenpåverkan från enskilda avloppsanläggningar - En studie av Gisekvarn, Trosa kommun.2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The lake Gisesjön is situated in the municipality Trosa, approximately 9 km southwest of Vagnhärad. It is an oligotrophic clearwater lake with a visibility depth of 5-6 meters, which is very rare in the region. Along the northeastern shore of lake Gisesjön, the area Gisekvarn is situated where about 120 summer cottages have been built up in three stages since the 1950’s. The area’s drinking-water is supplied from a number of common and private wells, whilst there are several different solutions for treatment of the sewage. Constructions for infiltration are dominating the area, although some have been in use since the area was founded, whereas others are recently-built.

    To protect the lake Gisesjön, Trosa municipality wanted to find out whether the lake is influenced by the houses in Gisekvarn, as well as if the groundwater in the area is influenced by the sewage constructions. The project comprised interviews of landowners of approximately 60 of the houses in the area regarding their use of the properties, water supply and sanitary standard, supplemented by investigations of the wells, the sewage constructions and the surrounding area. Water samples were taken from 28 of the private wells and at 26 spots along the shore which bordered the area. The water samples were analysed with respect to pH, hardness, conductivity, chloride, ammonium, nitrate, nitrite, phosphate, microorganisms, coliform bacteria and E. coli.

    The results showed that the water from the wells had a high pH-value and hardness, although the values were lower than the health limits of potable water. The conductivity as well as the amount of chloride and ammonium varied a lot in the area. In some of the wells the amount of chloride was so high that it could indicate an external source of pollution. Ammonia, phosphate and nitrate occurred in various amounts in the area, but even the highest amounts were far below the limits for potable water set up by the Swedish authorities. Likewise were the amounts of nitrite, which only occurred in two of the tested wells. The amounts of microorganisms as well as coliform bacteria were very varying in the area. One water sample did not have any microorganisms at all, whereas another had 5000 cfu/ml which made the water classified as drinking water with a remark. About a third of the tested wells contained so high amount of coliform bacteria that the water got a quality remark. Three of them were classified unsuitable water for drinking. Three wells had water containing E. coli bacteria which gave a quality remark and indicate influence from sewage.

    The lake’s pH was influenced along the shore, where it was lower compared to other parts of the lake. The water was soft at all test points and the values fall within a narrow range. Both the conductivity and the amounts of chloride were very low at all test points in the lake. The contents of phosphorus, nitrate and nitrite were so low that they couldn’t be measured. Ammonia however existed in various amounts along the shore, at some places the amounts were so high that the water could be classified as eutrophic, whereas at other sites no ammonia could be measured. Microorganisms occurred in various amounts along the whole tested part of the shore. Coliform bacteria and E. coli occurred in very various amounts, at some sites no bacteria could be found.

    The conclusion is that lake Gisesjön and the groundwater in Gisekvarn is slightly affected by the sewage constructions in the area. The principal proves are the various and occasionally high occurrences of above all chloride, ammonia and E. coli.

  • 336.
    Salimath, Abhilash
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    preliminary study of a Water, Hygiene and Ecological Sanitation project in a rural village in Bihar state of India.2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There are 2.6 billion people who have no access to "improved sanitation" all over the world, of which 814 million people live in India. As a result of this, people resort to open defecation and this causes serious damage to the people‟s health and also pollutes the surrounding environment. This thesis explores the sanitation situation in a village called Mohaddipur in the Bind Block of Nalanda district in the state of Bihar, India. This SIDA financed project will provide this village with a public toilet complex which will be constructed with the help of the community members and strive towards putting an end to open defecation which is practised by these community members of the study area. Through the sanitation facilities being provided it was also important to close the nutrient cycle loop between agriculture and sanitation and make this toilet complex sustainable in all aspects of sustainability: social, economic, environmental and cultural. The provision of Ecological Sanitation (ecosan) facilities through the implementation of CompostEra toilet units and technology, in the toilet complex, in both the „hardware‟ and the „software‟ aspects is studied in this thesis. Women and adolescent girls were sensitised through education on Menstrual Hygiene Management (MHM) to empower these women in this village of Mohaddipur to not only improve their health but to also get an opportunity to get an education and gain a livelihood. Participatory Action Research (PAR) method has been used in this study to empower the community of this village in order to increase the social, educational, gender and economic strength of the individuals. The results and subsequent discussion show the need to include communities in designing a sanitation facility and how capacity building is a very important step in this process. The findings suggest that the benefits of ecosan seem to be significant enough to outweigh the negative cultural sentiments regarding the use of human excrements.

  • 337.
    Salmistraro, Marco
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Mainstream deammonification reac-tor at low DO values and employing granular biomass.2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nitrogen removal from wastewater has been exstensively addressed by scientific literature in recent years; one of the most widely implemented technologies consists of the combination of partial nitritation and anaerobic ammonium oxidation (ANAMMOX). Compared to traditional nitrification and denitrification techniques such solution eliminates the requirement for an external carbon source and allows for a reduced production of excess sludge; furthermore, it brings down the costs associated to aeration by 60-90% and the emissions of CO2 by 90%. Similar techniques can turn out to be particularly interesting when stringent environmental regulations have to be met.

    At present, most of the dedicated research dwells on wastewater at high temperatures, high nitrogen loads and low organic content, as it is typical of sidestream effluents; this project, instead, is focused on mainstream wastewater, characterized by lower temperatures and nitrogen content, but higher COD values.

    At the center of the thesis is the application of a one-stage reactor treating synthetic mainstream municipal wastewater. The chosen approach consisted in maintaining low DO values, allowing for both for the establishment of a proper reaction environment and for the out-selection of nitrite oxidizers; granular biomass was employed for the experiment, aiming at effective biomass retention.

    The HRT value was gradually decreased, with a minimum at 6 hours. Resulting nitrogen removal rates proved to be satisfactory, with a maximum TN removal efficiency of 54%. Retention of biomass was also positively enhanced throughout the experiment, and yielded a final SRT value of 15.6 days.

    The whole process was then inserted into a more complete framework, accounting for possible energetic optimizations of similar treatment plants. Employing COD fractionation as a primary step paves the way for anaerobic digestion side processes, which can produce methane and ultimately provide energy for the main nitrogen removal step. Therefore, envisioning energy-sufficient water treatment processes seems a more and more feasible and realistic possibility.

  • 338.
    Salmistraro, Marco
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Fernández, I.
    Dosta, J.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Mata, J.
    Mainstream Deammonification: Preliminary Experience Employing Granular AOB-Enriched Biomass at Low DO Values2017In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 228, no 5, article id 178Article in journal (Refereed)
    Abstract [en]

    The deammonification process represents one of the most convenient pathways for nitrogen removal from wastewater. A great deal of scientific articles dwells on the treatment of sidestream fluxes, whereas applications to mainstream waters represent a novel field. Among the general challenges of deammonification, one of the most important is the effective selection of ammonia oxidizers (AOB) over nitrite oxidizers (NOB), but also the typical slow start-up periods. In addition to such issues, mainstream deammonification has to face water temperatures and alkalinity reserves lower than those of sidestream fluxes and higher content of organic matter. An attempt was made to tackle such challenges by employing a lab-scale plant; low dissolved oxygen (DO) values (average 0.78 mg/L) and granular AOB-enriched biomass were used in order to address exclusion of nitrite oxidizers. The granules also allowed better biomass retention. The hydraulic retention time (HRT) was established initially at 24 h and later decreased to 12 h, as to possibly enhance the performance of the reactor. After 52 days of operation, Anammox biomass was also inoculated to the reactor. The results showed a maximum nitrogen removal efficiency of 54%. Moreover, little quantities of nitrates were observed throughout the experiment (<5 mg N/L twice, under the limit of quantification the rest of the sampling days), meaning that NOB out-selection techniques worked properly. Retention of biomass was also positively addressed and yielded a final SRT value of 15.6 days. Therefore, the proposed solution for mainstream deammonification was demonstrated to be promising and more research would be necessary to optimize it.

  • 339.
    Sammeli, Maria
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Optimizing resources – studying ways to recycling phosphorus from onsite wastewater treatment plants.2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Eutrophication of the Baltic Sea has been an issue for decades and the pollution constantly continues with oxygen deficient bottoms and a damaged marine life as a result. One of the main causes of eutrophication are elevated levels of the nutrient phosphorus. Phosphorus leaks to the sea from various human activities such as agriculture, animal farming and sewage. In Sweden, the onsite wastewater treatment systems are a big problem since they load the Baltic Sea with nearly as much phosphorus as all Swedish municipal wastewater treatment plants. The need for a reduced impact on the Baltic Sea is major and the individual wastewater treatment systems must therefore be looked over.

    While phosphorus is a contributing factor to eutrophication, it is one of the most important nutrients for all life. Phosphorus builds up our DNA, helps transport of various substances in and out of our cells and provides energy to the cell's processes. We would simply not be able to survive without phosphorus. We ingest phosphorus through the food we eat, which in turn is dependent on fertilizers containing phosphorus. Phosphorus is mined from phosphate ore and the majority of it is used to produce fertilizers. Unfortunately, phosphate ore is not a finite resource and in the last few years it has been realized that the economically extractable phosphorus is a dwindling resource. To be able to produce food for the world's growing population, we need to find ways to recycle phosphorus. In individual drainage systems there is a large potential to catch up phosphorus and then reuse it on agricultural land. This thesis deals with the problems of onsite wastewater treatment systems and suggests measures to improve their status. Ways to recycle phosphorus in combination with having a well-functioning drainage is being investigated and difficulties about the regulations are being discussed. To recover phosphorus and at the same time reduce the burden on the environment should be seen as an incredibly important action, since our sea’s health is acute but lack of the nutrient could have devastating consequences.

  • 340.
    Sandhi, Arifin
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    ARSENIC REMOVAL BY PHYTOFILTRATION AND SILICON TREATMENT: A POTENTIAL SOLUTION FOR LOWERING ARSENIC CONCENTRATIONS IN FOOD CROPS2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Use of arsenic-rich groundwater for crop irrigation can increase the arsenic (As) content in food crops and act as a carcinogen, compromising human health. Using aquatic plant based phytofiltration is a potential eco-technique for removing arsenic from water. The aquatic moss species Warnstorfia fluitans grows naturally in mining areas in northern Sweden, where high concentrations of arsenic occur in lakes and rivers. This species was selected as a model for field, climate chamber and greenhouse studies on factors governing arsenic removal and arsenic phytofiltration of irrigation water. The arsenic and silicon (Si) concentrations in soil, water and plant samples were measured by AAS (atomic absorption spectrophotometry), while arsenite and arsenate species were determined using AAS combined with high pressure liquid chromatography (HPLC) with an anion exchange column. The arsenic content in grains of hybrid and local aromatic rice (Oryza sativa) cultivars with differing arsenic accumulation factor (AF) values was investigated in an arsenic hotspot in Bangladesh. The results showed that arsenic AF was important in identifying arsenic-safer rice cultivars for growing in an arsenic hotspot. The study based on silicon effect on arsenic uptake in lettuce showed that arsenic accumulation in lettuce (Lactuca sativa) could be reduced by silicon addition. The aquatic moss had good phytofiltration capacity, with fast arsenic removal of up to 82% from a medium with low arsenic concentration (1 µM). Extraction analysis showed that inorganic arsenic species were firmly bound inside moss tissue. Absorption of arsenic was relatively higher than adsorption in the moss. Regarding effects of different abiotic factors, plants were stressed at low pH (pH 2.5) and arsenic removal rate was lower from the medium, while arsenic efflux occurred in arsenate-treated medium at low (12°C) and high (30°C) temperature regimes. Besides these factors, low oxygenation increased the efficiency of arsenic removal from the medium. Finally, combining W. fluitans as a phytofilter with a lettuce crop on a constructed wetland significantly reduced the arsenic content in edible parts (leaves) of lettuce. Thus W. fluitans has great potential for use as an arsenic phytofilter in temperate regions.

  • 341.
    Sandhi, Arifin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Geochemistry and Ecotechnology.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Greger, Maria
    Stockholms Universitet, Institutionen för ekologi, miljö och botanik.
    Jacks, Gunnar
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Arsenic in irrigation water: a threat for rice cultivation?2013Conference paper (Refereed)
    Abstract [en]

    Frequent cultivation of high yielding rice varieties (HYV) for increased food production are the key reasons for massive application of groundwater based irrigation in the rice fields of Bangladesh. Including the Asian continent, more than half of the world’s population chooses rice as their staple food and it is already considered as one of the major sources of inorganic arsenic (As) intake in the human body through food stuffs. The water logged rice cultivation method also has influence on As accumulation in rice grain. The study area Matlab located in southeastern Bangladesh, which is identified as a prominent As hotspot with incidences of high level of As in the groundwater. The objective of this study was to find out the influence of irrigation water quality and soil on the level of As in rice grain and more specifically identify the influence of iron (Fe), silicon (Si) and phosphorus (P) in the soil on the As uptake in the rice grain. A number of previous laboratory based studies has found, all three elements exert significant control on the biogeochemical interactions of As in soils and uptake in the plants.

    The aim of this study was to compare the level of As in rice grain and bran of different HYVs and local rice varieties, grown in this region and to compare the results with the levels of Fe, Si and P in the irrigated soils. The ICP-OES based analysis showed that the total As concentration (5.74-16.78 mg Askg

    -1) in the soil samples from the rice fields of the area (n=9) has exceeded the average global As concentration in the crust and soils. The concentration of Fe and Si in the soil was positively correlated with total As in the soil. The As analogue, P was positively correlated with As (R2=0.52) in the soil samples. The arsenic concentration in the irrigation water of that particular area was (> 200 μg As l -1) The AAS based analysis found that the total arsenic concentration ranged (0.017- 0.23 mg As kg-1) in the grain whereas [Asbran] was higher compared with the grains. High level of Fe present in the soil could play a significant role on the bioavailability of As due to its sorption onto the surface of the Fe-oxide colloids and roots of the rice plants. To address the As bioavailability in the rice grain, the level of As influencing elements in both grain and bran should be focused in further investigation.

  • 342.
    Sandhi, Arifin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Department of Ecology, Environment and Plant Sciences, Stockholm University, SE 10691 Stockholm, Sweden.
    Greger, Maria
    Department of Ecology, Environment & Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden.
    Landberg, Tommy
    Department of Ecology, Environment & Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden.
    Jacks, Gunnar
    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.
    Arsenic concentrations in local aromatic and high-yielding hybrid rice cultivars and the potential health risk: A study in an arsenic hotspot2017In: Environmental Monitoring & Assessment, ISSN 0167-6369, E-ISSN 1573-2959, Vol. 189, no 184Article in journal (Refereed)
    Abstract [en]

    The presence of high levels of arsenic (As) in rice fields has negative effects on the health ofthose consuming rice as their subsistence food. This study determined the variation in total Asconcentration in local aromatic rice (LAR) (kalijira) and two high yielding varieties (HYVs)(BRRI dhan 32 and BRRI dhan 28) grown in paddy fields in Matlab, Bangladesh, an As hotspot with elevated As levels in groundwater. Mature rice grain samples and soil samples were collected from different paddy fields and the As concentrations in both the de-husked grains and the husks of the three rice cultivars were analysed to identify the safest of the threecultivars for human consumption. The results showed that the total As concentration washigher (0.09-0.21 mg As kg-1) in the de-husked grains of LAR than in the husks, while theopposite was found for the HYV rice. Moreover, the As concentration in soil samples was 2-to 5-fold higher for the LAR than for the HYVs, but the As accumulation factor (AF) waslower in the LAR (0.2-0.4%) than in the HYVs (0.9-1%). Thus, LAR can be considered thesafest of the three cultivars for human consumption owing to its low AF value. Furthermore,due to the low AF, growing LAR instead of HYVs in soils with slightly elevated As levelscould help improve the food safety level in the food chain.

  • 343.
    Sandhi, Arifin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Department of Ecology, Environment and Plant Sciences, Stockholm University, SE 10691 Stockholm, Sweden.
    Landberg, Tommy
    Department of Ecology, Environment & Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden.
    Greger, Maria
    Department of Ecology, Environment & Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden.
    Effect of pH, temperature, and oxygenation on arsenic phytofiltration by aquatic moss (Warnstorfia fluitans)2018In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 6, no 4, p. 3918-3925Article in journal (Refereed)
    Abstract [en]

    Phytofiltration of arsenic (As)-contaminated water could reduce As in irrigation and surface water. In a previous study, we found that the aquatic moss Warnstorfia fluitans efficiently removes arsenic from water contaminated with arsenate and arsenite. This work investigates how factors such as pH, temperature, and oxygenation influence As removal, since these factors vary in the environment. Plants were grown in a medium with 5 or 10 μM arsenite or arsenate and: 1) a pH of 2.5, 6.5, or 9.5; 2) a temperature of 12, 20, or 30 °C; and 3) oxygenation of <2 or 13 mg O2 L−1. Removal of As was monitored over 48–96 h, and the content and speciation of As were analysed in moss plants at the termination of the experiments. Results indicate that As removal was faster in arsenite than arsenate solutions. Arsenic removal from arsenite solution was the fastest, i.e., 80–90% within 2 h, at pH 6.5 and 9.5 and at 20 and 30 °C. At pH 2.5, plants were stressed and the net removal was low throughout the treatment period. Arsenic removal was more efficient at low than high oxygenation levels. Besides this, no As net efflux process was seen in the water system except after 48 h in arsenate-treated medium in high-temperature (30 °C) regimes. Regardless of As species added, usually only arsenite was found in the plants after treatment. Most internal As, i.e., 95% in the arsenate and 85% in the arsenite treatments, was firmly bound to the tissue. The study found that at 20 °C, neutral pH, and low oxygenation, this aquatic moss has great potential for As phytofiltration.

  • 344.
    Sandhi, Arifin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Department of Ecology, Environment and Plant Sciences, Stockholm University, SE 10691 Stockholm, Sweden.
    Landberg, Tommy
    Department of Ecology, Environment & Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden.
    Greger, Maria
    Department of Ecology, Environment & Plant Sciences, Stockholm University, SE-10691 Stockholm, Sweden.
    Phytofiltration of arsenic by aquatic moss (Warnstorfia fluitans)2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424Article in journal (Refereed)
    Abstract [en]

    This work investigates whether aquatic moss (Warnstorfia fluitans) originating from an arsenic (As)-contaminated wetland close to a mine tailings impoundment may be used for phytofiltration of As. The aim was to elucidate the capacity of W. fluitans to remove As from arsenite and arsenate contaminated water, how nutrients affect the As uptake and the proportion of As adsorption and absorption by the moss plant, which consists of dead and living parts.

    Arsenic removal from 0, 1, or 10% Hoagland nutrient solution containing 0–100 μM arsenate was followed over 192 h, and the total As in aquatic moss after treatment was analysed. The uptake and speciation of As in moss cultivated in water containing 10 μM arsenate or arsenite were examined as As uptake in living (absorption + adsorption) and dead (adsorption) plant parts.

    Results indicated that W. fluitans removed up to 82% of As from the water within one hour when 1 μM arsenate was added in the absence of nutrients. The removal time increased with greater nutrient and As concentrations. Up to 100 μM As had no toxic effect on the plant biomass. Both arsenite and arsenate were removed from the solution to similar extents and, independent of the As species added, more arsenate than arsenite was found in the plant. Of the As taken up, over 90% was firmly bound to the tissue, a possible mechanism for resisting high As concentrations. Arsenic was both absorbed and adsorbed by the moss, and twice as much As was found in living parts as in dead moss tissue. This study revealed that W. fluitans has potential to serve as a phytofilter for removing As from As-contaminated water without displaying any toxic effects of the metalloid.

  • 345.
    Sedell, Linde
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Sunesson, Philip
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Kostnadsberäkningar vid grundläggning genom jordlagermodellering i GIS-program – Vid väg 268.2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Rapporten ämnar presentera ett sätt att utföra kostnadsberäkningar för grundläggning längs en vägsträcka utan provborrningar, samt utreda hur mycket olika alternativ till förstärkningsåtgärder skulle kosta. Detta kommer ske genom att, med hjälp av de extensiva geodatabaser som finns att tillgå, modellera förutsättningarna och på så vis kunna eliminera behoven av eller alternativt minska mängden provborrningar. För att illustrera metoden kommer ombyggnationen av en väg i Stockholm att kostnadskalkyleras. För den väg som valts utreder Trafikverket två alternativa vägkorridorer och denna rapport kommer även att presentera en tredje. Resultatet visar att den vägsträckning som presenteras i rapporten skulle bli den billigaste ur grundläggningssynvinkel då den består av minst lera och torv. De andra vägalternativen är relativt jämna i kostnad och den billigaste metoden för grundförstärkning är vertikaldränering i alla tre fall.

  • 346.
    Seidevall Byström, Lilliy
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Vinterviken- studie av afallsegenskaper hos bottensediment.2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Förorenade områden är ett problem då föroreningarna kan påverka hälsa och miljö. När förorenade områden saneras genom schaktning eller muddring utgör schaktmas-sorna ett avfall. Avfallsklassificering är en viktig del vid sanering av förorenade områ-den. Det finns mycket lagstiftning att förhålla sig till och många analysmetoder att välja på. Detta kandidatarbete syftar till att avfallklassificera och identifiera aktuell de-poni för bottensedimenten i Vinterviken i södra Stockholm samt diskutera resultatens relevans mot bakgrund av forskning på området. Resultaten visar att bottensedimen-ten utgör ett icke farligt avfall som på grund av sin TOC halt inte kan placeras på de-poni utan att genomgå förbehandling eller att dispens från gränsvärdena ges. Det finns osäkerhet i de reglerade analysmetoderna och redovisade avfallsegenskaper kan på denna grund ifrågasättas.

  • 347. Senapati, N.
    et al.
    Jansson, Per-Erik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Smith, P.
    Chabbi, A.
    Modelling heat, water and carbon fluxes in mown grassland under multi-objective and multi-criteria constraints2016In: Environmental Modelling & Software, ISSN 1364-8152, E-ISSN 1873-6726, Vol. 80, p. 201-224Article in journal (Refereed)
    Abstract [en]

    A Monte Carlo-based calibration and uncertainty assessment was performed for heat, water and carbon (C) fluxes, simulated by a soil-plant-atmosphere system model (CoupModel), in mown grassland. Impact of different multi-objective and multi-criteria constraints was investigated on model performance and parameter behaviour. Good agreements between hourly modelled and measurement data were obtained for latent and sensible heat fluxes (R2 = 0.61, ME = 0.48 MJ m-2 day-1), soil water contents (R2 = 0.68, ME = 0.34%) and carbon-dioxide flux (R2 = 0.60, ME = -0.18 g C m-2 day-1). Multi-objective and multi-criteria constraints were efficient in parameter conditioning, reducing simulation uncertainty and identifying critical parameters. Enforcing multi-constraints separately on heat, water and C processes resulted in the highest model improvement for that specific process, including some improvement too for other processes. Imposing multi-constraints on all groups of variables, associated with heat, water and C fluxes together, resulted in general effective parameters conditioning and model improvement.

  • 348. Setegn, S. G.
    et al.
    Melesse, A. M.
    Rayner, D.
    Dargahi, Bijan
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Climate change impact on water resources and adaptation strategies in the Blue Nile River Basin2014In: Nile River Basin: Ecohydrological Challenges, Climate Change and Hydropolitics, Springer International Publishing , 2014, p. 389-404Chapter in book (Other academic)
    Abstract [en]

    We compared projected changes in precipitation and temperature across global climate models (GCMs) for two future periods to get an indication of the consistency of the projected changes in the Lake Tana subbasin of the Blue Nile basin. We found that the models projected temperature increases of around 2∈°C to 5∈°C for 2080-2100, depending on the model and emission scenario. The interquartile ranges of the projected temperature increases for 2070-2100 for the three emission scenarios show 2.0-4.4∈°C in the wet season and 2.2-4.9∈°C in the dry season. The ensemble of GCMs we examined includes models that project increases and decreases in seasonal precipitation. The interquartile ranges of the projected rainfall changes for 2070-2100 for the three emission scenarios show -∈13 to +∈12∈% in the wet season and -∈14 to +∈16∈% in the dry season. The study investigated how changes in temperature and precipitation might translate into changes in streamflows and other hydrological components using downscaled outputs from different climate models. The direction of streamflow changes followed the direction of changes in rainfall. The responses of evapotranspiration, soil moisture (SW), and groundwater (GW) were also examined, and it was found that changes in GW flow may be a significant component of the changes in streamflow. The effect of climate change has the potential to cause agricultural drought, unless there is ample water available for irrigation. However, a reduction in rainfall may cause reduced GW recharge, which would significantly reduce its contribution to streamflow. Lake Tana is highly sensitive to variations in rainfall, as well as in river inflows and evaporation.

  • 349. Shabanimashcool, M.
    et al.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering. Group of Engineering Geology and Geophysics.
    Li, C. C.
    Discontinuous Modelling of Stratum Cave-in in a Longwall Coal Mine in the Arctic Area2014In: Geotechnical and Geological Engineering, ISSN 0960-3182, E-ISSN 1573-1529, Vol. 32, no 5, p. 1239-1252Article in journal (Refereed)
    Abstract [en]

    This paper presents a discontinuous numerical approach for studying roof cave-in mechanisms and obtaining the required support capacity of longwall shields in a case study site, the Svea Nord coal mine in Svalbard. The block size in the roof strata and the mechanical parameters of the discontinuities for the numerical model were obtained through back-calculations. The back-calculations were conducted with a statistical method of design of experiment. Numerical simulations revealed that voussoir jointed beams are formed before the first cave-in occurs. The maximum deflection of a roof stratum in the study site prior to the first cave-in is about 70 % of the stratum thickness. The maximum span of the roof strata prior to the first cave-in depends upon the in situ horizontal stress state. The roof beams have a large stable span when they are subjected to high horizontal stress; but horizontal stress would increase the possibility of rock crushing in deflected roof beams. The simulations and field measurements show no periodic weighting on the longwall shields in the study site. Stiff and strong roof beams would result in large first and periodic cave-in distances. As a consequence of having large cave-in distances, the longwall shields must have high load capacity, which can be calculated by the presented numerical approach.

  • 350.
    Singh, Durgesh Kumar
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Assessment of nutrient loading in lake Ringsjön from the catchment of Hörbyån Creek in Southern Sweden.2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Lake Ringsjön, located in south of Sweden, has been subject of eutrophication since 1950s and received several restoration efforts. Latest restoration effort, “Project Ringsjön”, was proposed in 2003 to improve lake condition against eutrophication by reducing nutrient concentration.

    This study was done to assess the nutrient loading into the lake from the catchment of Hörbyån Creek, which is discharging into the lake from southeast. Study addresses the nutrient loading conditions from Hörbyån Creek before and after the implementation of “Project Ringsjön” in 1998 and 2010 respectively. Thus a water quality analysis was performed to observe the changes in total nitrogen and total phosphorus concentration in Hörbyån Creek between these years. Effort was also made to investigate nutrients contribution of different watersheds in the catchment.

    This study also addresses the effect of seasonal variability and land use on nutrient loading. In order to achieve objectives, annual and monthly water quality modelling was performed on the river. HEC-RAS software was used to simulate water quality variables loading from catchment into the lake, such as nitrates, nitrite, ammonium, organic nitrogen, inorganic phosphorus and orthophosphate. Results indicated increase in average annual total nitrogen concentration from 4.18 mg/l to 4.56 mg/l and reduction in average annual total phosphorus concentration from 0.165 mg/l to 0.083 mg/l in the water discharging into the lake from catchment. The watershed occupying mostly agriculture area was observed to have maximum nutrients contribution, which might be due to high fertilizer leakage. It was also observed that maximum nutrient loading was taking place in November and March; probably due to high runoff generated from precipitation and snow melting that carried additional nutrients to the water bodies. Results also indicated that the studied catchment area was contributing high nutrient concentration for eutrophication in both years; however, there was small decrease in total phosphorus concentration in 2010 compare to 1998.

456789 301 - 350 of 421
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf