Change search
Refine search result
1234567 151 - 200 of 1279
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.
  • 151.
    Carstens, Christoffer
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Hydrological dispersion in a coastal catchmentArticle in journal (Other academic)
  • 152.
    Carstens, Christoffer
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Destouni, Georgia
    Stockholm University.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Wave-power potentialfor reducing hypoxia in the Baltic SeaArticle in journal (Other academic)
  • 153.
    Cederwall, klas
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Dams, flood protection, and risk2012In: Encyclopedia of Earth Sciences Series, Springer Netherlands, 2012, p. 207-212Chapter in book (Refereed)
  • 154.
    Cema, Grzegorz
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Comparative study on different Anammox systems2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The legal requirements for wastewater discharge into environment, especially to zones exposed to eutrophication, lately became stricter. Nowadays wastewater treatment plants have to manage with the new rules and assure better biogenic elements’ removal, in comparison with the past. There are some well-known methods of diminishing concentrations of these compounds, but they are ineffective in case of nitrogen-rich streams, as landfill leachate or reject waters from dewatering of digested sludge. This wastewater disturbs conventional processes of nitrification-denitrification and raise necessity of building bigger tanks. The partial nitritation followed by Anaerobic Ammonium Oxidation (Anammox) process appear to be an excellent alternative for traditional nitrification/denitrification. The process was investigated in three different reactors – Membrane Bioreactor (MBR), Moving Bed Biofilm Reactor (MBBR) and Rotating Biological Contactor (RBC). The process was evaluated in two options: as a two-stage process performed in two separate reactors and as a one-stage process. The two-step process, in spite of very low nitrogen removal rates, assured very high nitrogen removal efficiency, exceeding even 90% in case of the MBBR. However, obtained results revealed that the one-step system is a better option than the two-step system, no matter, what kind of nitrogen-rich stream is taken into consideration. Moreover, the one-step process was much less complicated in operation. Performed research confirmed a hypothesis, that the oxygen concentration in the bulk liquid and the nitrite production rate are the limiting factors for the Anammox reaction in a single reactor. In order to make a quick and simple determination of bacteria activity, the Oxygen Uptake Rate (OUR) tests were shown as an excellent tool for evaluation of the current bacteria activity reliably, and without a need of using expensive reagents. It was also shown, that partial nitritation/Anammox process, could be successfully applied at temperatures much lower than the optimum value. Performed Fluorescent in situ Hybridization (FISH) analyses, proved that the Anammox bacteria were mainly responsible for the nitrogen removal process.

  • 155.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Pietrala, Aleksandra
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Activity assessment and kinetic parameter estimation in single stage partial nitritation/Anammox2009In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336Article in journal (Other academic)
  • 156.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Surmacz-Gorska, J.
    Activated sludge and biofilm in the Anammox reactor: Cooperation or competition?2007In: Integration and optimisation of urban sanitation systems: Proceedings of Polish-Swedish seminars / [ed] E. Plaza, E. Levlin, 2007, p. 129-138Conference paper (Other academic)
  • 157.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Surmacz-Górska, J
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Miksch, K
    Study on evaluation of kinetic parameters for Anammox process2005In: Proceedings of the IWA Specialized Conference Nutrient Management in Wastewater Treatment Processes and Recycle Streams, 2005, p. 379-388Conference paper (Other academic)
  • 158.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Surmacz-Gorska, J.
    Dissolved oxygen as a factor influencing nitrogen removal rates in a one-stage system with partial nitritation and Anammox process2011In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 64, no 5, p. 1009-1015Article in journal (Refereed)
    Abstract [en]

    A biofilm system with Kaldnes biofilm carrier was used in these studies to cultivate bacteria responsible for both partial nitritation and Anammox processes. Due to co-existence of oxygen and oxygen-free zones within the biofilm depth, both processes can occur in a single reactor. Oxygen that inhibits the Anammox process is consumed in the outer layer of the biofilm and in this way Anammox bacteria are protected from oxygen. The impact of oxygen concentration on nitrogen removal rates was investigated in the pilot plant (2.1 m(3)), supplied with reject water from the Himmerfjarden Waste Water Treatment Plant. The results of batch tests showed that the highest nitrogen removal rates were obtained for a dissolved oxygen (DO) concentration around 3 g O(2) m(-3). At a DO concentration of 4 g O(2) m(-3), an increase of nitrite and nitrate nitrogen concentrations in the batch reactor were observed. The average nitrogen removal rate in the pilot plant during a whole operating period oscillated around 1.3 g N m(-2)d(-1) (0.3 +/- 0.1 kg N m(-3)d(-1)) at the average dissolved oxygen concentration of 2.3 g O(2) m(-3). The maximum value of a nitrogen removal rate amounted to 1.9 g N m(-2)d(-1) (0.47 kg N m(-3)d(-1)) and was observed for a DO concentration equal to 2.5 g O(2) m(-3). It was observed that increase of biofilm thickness during the operational period, had no influence on nitrogen removal rates in the pilot plant.

  • 159.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Surmacz-Górska, J.
    Dissolved oxygen as a factor influencing nitrogen removal rates in a one-stage system with partial nitritation and Anammox process2008In: Proceedings of the IWA Biofilm Technologies Conference, 8 – 10 January 2008, Singapore, 2008Conference paper (Other academic)
  • 160.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Raszka, Anna
    Silesian University of Technology, Environmental Biotechnology Department.
    Stachurski, Arkadiusz
    Kunda, Katarzyna
    Surmacz-Górska, Joanna
    Silesian University of Technology, Environmental Biotechnology Department.
    Płaza, Elżbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    A one-stage system with partial nitritation and Anammox processes in Rotating Biological Contactor (RBC) for treating landfill leachateIn: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336Article in journal (Other academic)
    Abstract [en]

    One of the major aspects associated with landfilling of solid wastes is related to the discharge of leachate into environment. Leachates with high ammonium nitrogen content are generally difficult to effective treat in conventional biological treatment processes. Therefore, it brings a requirement of developing new processes and technologies. Additionally, treatment procedures must consider small flow rates of leachate. The Rotating Biological Contactor (RBC) is a good example of technology for treatment such wastewaters, because of its excellent shock and toxic loading capabilities, simple process control and low energy requirements. The main objective of the presented research was to investigate a simultaneous partial nitritation/Anammox process in the rotating biological contactor. For this purpose, the lab-scale reactor was fed with real landfill leachate from two municipal landfill sites in Gliwice and Zabrze (Poland). The reactor was highly loaded up to 7 g N m-2d-1 and it was possible to obtain the maximum inorganic nitrogen removal rate of 6.2 g N m-2d-1. Achieved results proved the possibility of efficient inorganic nitrogen removal by means of partial nitritation/ Anammox process in the temperature around 20°C.

  • 161.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Szatkowska, Beata
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Płaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Surmacz-Górska, Joanna
    Nitrogen removal rates at a technical-scale pilot plant with the one-stage partial nitritation/Anammox process.2006In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 54, no 8, p. 209-217Article in journal (Refereed)
    Abstract [en]

    Traditional nitrification/denitrification is not suitable for nitrogen removal when wastewater contains high concentrations of ammonium nitrogen and low concentrations of biodegradable carbon. Recently, a deammonification process was developed and proposed as a new technology for treatment of such streams. This process relies on a stable interaction between aerobic bacteria Nitrosomonas, that accomplish partial nitritation and anaerobic bacteria Planctomycetales, which conduct the Anammox reaction. Simultaneous performance of these two processes can lead to a complete autotrophic nitrogen removal in one single reactor. The experiments where nitrogen was removed in one reactor were performed at a technical-scale moving-bed pilot plant, filled with Kaldnes rings and supplied with supernatant after dewatering of digested sludge. It was found that a nitrogen removal rate obtained at the pilot plant was 1.9 g m(-2) d(-1). Parallel to the pilot plant run, a series of batch tests were carried out under anoxic and aerobic conditions. Within the batch tests, where the pilot plant's conditions were simulated, removal rates reached up to 3g N m(-2) d(-1). Moreover, the batch tests with inhibition of Nitrosomonas showed that only the Anammox bacteria (not anoxic removal by Nitrosomonas) are responsible for nitrogen removal.

  • 162. Cema, Grzegorz
    et al.
    Trela, Jozef
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Surmacz-Gorska, J.
    Partial nitritation/Anammox process: from two-step towards one step process2010In: Proceedings IWA Word Water Congress, 2010Conference paper (Refereed)
  • 163.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Wiszniowski, J
    Zabczynski, S
    Raszka, A
    Surmacz-Gorska, J
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Simultaneous nitrification, anammox and denitrification in aerobic rotating biological contactor (RBC) treating landfill leachate2008In: Management of Pollutant Emission from Landfills and Sludge: selected papers from the International Workshop on Management of Pollutant Emission from Landfills and Sludge, Kazimierz Dolny, Poland, 16-19 September, 2006 / [ed] M. Pawlowska, L. Pawlowski, London: Taylor & Francis Group, 2008, p. 211-218Chapter in book (Refereed)
    Abstract [en]

    Leachate from landfills is a highly complex polluted wastewater. Landfill leachate with a high concentration of ammonium nitrogen is generally difficult to treat efficiently. Furthermore, it can be very expensive when there is a lack of an easily biodegradable carbon source. Combination of the nitrification/denitrification with the Anammox process can be a very attractive alternative. For the purpose of this study, a Rotating Biological Contactor (RBC) was used. The main objective of the research was to investigate the performance of the Anammox process that occurs together with heterotrophic denitrication in the same RBC. During the operation period, the acclimation of biofilm to the Anammox process was successful at temperature not exceeding 20C. Apparently, the process was not affected by a high concentration of nitrite up to 100 g NO2 Nm3. Additionally, it was shown that the Stover-Kineannon model could be used for description of the ammonium and nitrite removal rates.

    Leachate from landfills is a highly complex polluted wastewater. Landfill leachate with a high concentration of ammonium nitrogen is generally difficult to treat efficiently. Furthermore, it can be very expensive when there is a lack of an easily biodegradable carbon source. Combination of the nitrification/denitrification with the Anammox process can be a very attractive alternative. For the purpose of this study, a Rotating Biological Contactor (RBC) was used. The main objective of the research was to investigate the performance of the Anammox process that occurs together with heterotrophic denitrication in the same RBC. During the operation period, the acclimation of biofilm to the Anammox process was successful at temperature not exceeding 20C. Apparently, the process was not affected by a high concentration of nitrite up to 100 g NO2 Nm³. Additionally, it was shown that the Stover-Kineannon model could be used for description of the ammonium and nitrite removal rates.

  • 164.
    Cema, Grzegorz
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Wiszniowski, J.
    Zabczynski, S.
    Zablocka-Godlewska, E.
    Raszka, A.
    Surmacz-Górska, J.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water, Sewage and Waste technology.
    Simultaneous nitrification, anammox and denitrification in aerobic rotating biological contactor (RBC) treating landfill leachate2006In: Proceedings of the workshop in framework of the Network of Excellence on “Pathways of pollutants from landfills and sludge processing to air and water-soil systems and mitigation strategies of their impact on the ecosystems”, 2006Conference paper (Other academic)
  • 165. Chan, T.
    et al.
    Christiansson, R.
    Boulton, G. S.
    Ericsson, L. O.
    Hartikainen, J.
    Jensen, M. R.
    Ivars, Diego Mas
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Stanchell, F. W.
    Vistrand, P.
    Wallroth, T.
    DECOVALEX III BMT3/BENCHPAR WP4: The thermo-hydro-mechanical responses to a glacial cycle and their potential implications for deep geological disposal of nuclear fuel waste in a fractured crystalline rock mass2005In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 42, no 5-6, p. 805-827Article in journal (Refereed)
    Abstract [en]

    A number of studies related to past and on-going deep repository performance assessments have identified glaciation/ deglaciation as major future events in the next few hundred thousand years capable of causing significant impact on the long term performance of the repository system. Benchmark Test 3 (BMT3) of the international DECOVALEX III project has been designed to provide an illustrative example that explores the mechanical and hydraulic response of a fractured crystalline rock mass to a period of glaciation. The primary purpose of this numerical study is to investigate whether transient events associated with a glacial cycle could significantly influence the performance of a deep geological repository in a crystalline Shield setting. A conceptual site-scale (tens of kilometres) hydro-mechanical (HM) model was assembled based primarily on site-specific litho-structural, hydrogeological and geomechanical data from the Whiteshell Research Area in the Canadian Shield, with simplification and generalization. Continental glaciological modelling of the Laurentide ice sheet through the last glacial cycle lasting approximately 100,000 years suggests that this site was glaciated at about 60 ka and between about 22.5 and 11 ka before present with maximum ice sheet thickness reaching 2500 m and maximum basal water pressure head reaching 2000m. The ice-sheet/drainage model was scaled down to generate spatially and temporally variable hydraulic and mechanical glaciated surface boundary conditions for site-scale subsurface HM modelling and permafrost modelling. Under extreme periglacial conditions permafrost was able to develop down to the assumed 500-m repository horizon. Two- and three-dimensional coupled HM finite-element simulations indicate: during ice-sheet advance there is rapid rise in hydraulic head, high transient hydraulic gradients and high groundwater velocities 2-3 orders of magnitude higher than under nonglacial conditions; surface water recharges deeper than under nonglacial conditions; upon ice-sheet retreat, the gradients reverse; fracture zone network geometry, interconnectivity and hydraulic properties significantly influence flow domain response; residual elevated heads are preserved for 10,000s in the low-diffusivity rock; and no hydraulic jacking or shear failure occurs at depth. It was found that transient coupled modelling is necessary to capture the essence of glacial effects on Performance Assessment. Model dimensionality also significantly affects simulated results.

  • 166. Chasset, Coralie
    et al.
    Jarsjo, Jerker
    Erlstrom, Mikael
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Destouni, Georgia
    Scenario simulations of CO(2) injection feasibility, plume migration and storage in a saline aquifer, Scania, Sweden2011In: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 5, no 5, p. 1303-1318Article in journal (Refereed)
    Abstract [en]

    Deep saline aquifers have large capacity for geological CO(2) storage, but are generally not as well characterized as petroleum reservoirs. We here aim at quantifying effects of uncertain hydraulic parameters and uncertain stratigraphy on CO(2) injectivity and migration, and provide a first feasibility study of pilot-scale CO(2) injection into a multilayered saline aquifer system in southwest Scania, Sweden. Four main scenarios are developed, corresponding to different possible interpretations of available site data. Simulation results show that, on the one hand, stratigraphic uncertainty (presence/absence of a thin mudstone/claystone layer above the target storage formation) leads to large differences in predicted CO(2) storage in the target formation at the end of the test (ranging between 11% and 98% of injected CO(2) remaining), whereas other parameter uncertainty (in formation and cap rock permeabilities) has small impact. On the other hand, the latter has large impact on predicted injectivity, on which stratigraphic uncertainty has small impact. Salt precipitation at the border of the target storage formation affects CO(2) injectivity for all considered scenarios and injection rates. At low injection rates, salt is deposited also within the formation, considerably reducing its availability for CO(2) storage.

  • 167. Chatterjee, D.
    et al.
    Biswas, A.
    Bhowmick, S.
    Halder, D.
    Hazra, R.
    Majumder, S.
    Mukherjee-Goswami, A.
    Saha, D.
    Nath, B.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Geochemistry of arsenic in Bengal Delta Plain (West Bengal, India)2010In: Arsenic in Geosphere and Human Diseases, As 2010 - 3rd International Congress: Arsenic in the Environment, 2010, p. 125-126Conference paper (Refereed)
  • 168.
    Chatterjee, D.
    et al.
    Univ Kalyani, Dept Chem, Nadia 741235, India.;Heritage Inst Technol, Dept Chem Technol, Kolkata 700107, India..
    Nath, B.
    Univ Kalyani, Dept Chem, Nadia 741235, India.;Univ Sydney, Sch Geosci, Sydney, NSW 2006, Australia..
    Chakraborty, S.
    Univ Kalyani, Dept Chem, Nadia 741235, India.;Kanchrapara Coll, Dept Chem, Kanchrapara 743145, India..
    Majumder, S.
    Univ Kalyani, Dept Chem, Nadia 741235, India.;Univ Girona, Dept Chem, Girona 17071, Spain..
    Biswas, Ashis
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630). Univ Kalyani, Dept Chem, Nadia 741235, India..
    Bhomick, S.
    Univ Kalyani, Dept Chem, Nadia 741235, India.;Univ Girona, Dept Chem, Girona 17071, Spain..
    Halder, Dipti
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630). Univ Kalyani, Dept Chem, Nadia 741235, India..
    Mondal, P.
    Univ Kalyani, Dept Chem, Nadia 741235, India.;Katholieke Univ Leuven, Dept Chem Engn, B-3001 Heverlee, Belgium..
    Kundu, A.
    Univ Kalyani, Dept Chem, Nadia 741235, India..
    Saha, D.
    Univ Kalyani, Dept Chem, Nadia 741235, India..
    Barman, S.
    Univ Kalyani, Dept Chem, Nadia 741235, India..
    Biswas, U.
    Univ Kalyani, Dept Chem, Nadia 741235, India..
    Saha, I.
    Univ Kalyani, Dept Chem, Nadia 741235, India..
    Das, A.
    Univ Kalyani, Dept Chem, Nadia 741235, India..
    Sarkar, S.
    Univ Kalyani, Dept Chem, Nadia 741235, India..
    Groundwater arsenic in the fluvial Bengal plains: geochemistry and mitigation2013In: PROCEEDINGS OF THE FOURTEENTH INTERNATIONAL SYMPOSIUM ON WATER-ROCK INTERACTION, WRI 14 / [ed] Hellmann, R Pitsch, H, ELSEVIER SCIENCE BV , 2013, p. 143-146Conference paper (Refereed)
    Abstract [en]

    The water quality and chemistry of the groundwater of the fluvial Bengal plains have been investigated. It has been found that shallow aquifers (< 50 m bgl) are contaminated in a few pockets, surrounded by areas with low arsenic (As)/As-free groundwater, while the deeper aquifer (> 100 m bgl) is generally free from As (< 10 mu g/L). It also reveals that multiple As mobilization processes are occurring simultaneously, rather than any single geochemical process. An attempt has been made to demonstrate the degree of As heterogeneity with groundwater quality, and this has been followed by a few local conditions. The study further suggests that the As distribution (spatio-vertical) helps to identify safe shallow aquifers, and several signatures (colour of the sediments /land use pattern/ geomorphological features /local recharge events) are apparent that can be useful for formulating long-term mitigation options.

  • 169. Chatterjee, Debashis
    et al.
    Haider, Dipti
    Majumder, Santanu
    Biswas, Ashis
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Nath, Bibhash
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Bhowmick, Subhamoy
    Mukherjee-Goswami, Aishwarya
    Saha, Debasree
    Hazra, Rasmani
    Maity, Palash B.
    Chatterjee, Debankur
    Mukherjee, Abhijit
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Assessment of arsenic exposure from groundwater and rice in Bengal Delta Region, West Bengal, India2010In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 44, no 19, p. 5803-5812Article in journal (Refereed)
    Abstract [en]

    Arsenic (As) induced identifiable health outcomes are now spreading across Indian subcontinent with continuous discovery of high As concentrations in groundwater. This study deals with groundwater hydrochemistry vis-a-vis As exposure assessment among rural population in Chakdaha block, West Bengal, India. The water quality survey reveals that 96% of the tubewells exceed WHO guideline value (10 mu g/L of As). The groundwaters are generally anoxic (-283 to -22 mV) with circum-neutral pH (6.3 to 7.8). The hydrochemistry is dominated by HCO3- (208 to 440 mg/L), Ca2+ (79 to 178 mg/L) and Mg2+ (17 to 45 mg/L) ions along with high concentrations of As-T (As total, below detection limit to 0.29 mg/L), Fe-T (Fe total, 1.2 to 16 mg/L), and Fe(II) (0.74 to 16 mg/L). The result demonstrates that Fe(II)-Fe(III) cycling is the dominant process for the release of As from aquifer sediments to groundwater (and vice versa), which is mainly controlled by the local biogeochemical conditions. The exposure scenario reveals that the consumption of groundwater and rice are the major pathways of As accumulation in human body, which is explained by the dietary habit of the surveyed population. Finally, regular awareness campaign is essential as part of the management and prevention of health outcomes. (c) 2010 Elsevier Ltd. All rights reserved.

  • 170. Chen, C. -Y
    et al.
    Maity, J. P.
    Bundschuh, Jochen
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Baba, A.
    Gunduz, O.
    Occurrence of arsenic and related microbial signature of hydrothermal systems in Western Turkey2012In: Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment, 2012, p. 486-488Conference paper (Refereed)
    Abstract [en]

    The naturally occurring aqueous Arsenic (As) and other toxic elements are found around the world. The present study concentrates on arsenic concentrations, speciation and related microbial diversity in a hydrothermal system in Western Turkey. The surface temperatures of hot springs reach up to 90°C and deep well (reservoir) temperatures vary in the range of 40 to 230°C. The elements such as As, B, Br, Ba, Cr, Fe, Mn, V and Zn are found in high concentration in hydrothermal waters. Hydrogeochemically, Seferihisar hot spring exhibited a Na-Cl water type. On the other hand, Karahayit, Pamukkale, Emirfaki, Alaşehir and Sart exhibit a Ca-HCO 3 water type and Çitgöl exhibited a Na-HCO 3-SO 4 water type. The arsenic (As) concentrations in geothermal waters of Western Anatolia have been detected to range from 0.03 mg/L to 1.5 mg/L, including Buharkent (İnalti) (1.50 ± 0.005 mg/L), Kizildere (1.13 ± 0.005 mg/L), Eynal (0.71 ± 0.005 mg/L) and Sarayköy (0.06 ± 0.004 mg/L). Arsenic (III) is the dominant species in geothermal water of Western Anatolia. The 16S rRNA gene sequences of bacterial diversity show that the thermophilic, sulfur/thiosulfate-oxidizing bacterium (Thiobacter subterraneus) is present in Kula geothermal water and mesophilic sulfur- and thiosulfate-oxidizing Sulfurovum lithotrophicum bacterium occurs in Sarayköy geothermal spring. Also, Bacillus fumarioli, (a thermophilic, aerobic endospore forming bacterium growing on (NH 4) 2 SO 4, MgSO 4 and MnSO 4 at 50-55°C), Schlegelella thermodepolymerans and Methylocaldum szegediense are rich in geothermal water.

  • 171. Chen, Y.
    et al.
    Zhou, C.
    Tong, Fuguo
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Numerical model for fully coupled THM processes with multiphase flow and code validation2009In: Chinese Journal of Rock Mechanics and Engineering, ISSN 1000-6915, Vol. 28, no 4, p. 649-665Article in journal (Refereed)
    Abstract [en]

    A numerical model for fully coupled THM processes with multiphase flow in porous media was developed based on the momentum, mass and energy conservation laws of the continuum mechanics and the averaging approach of the mixture theory over a solid-liquid-gas three-phase system. To characterize multiphase THM coupling and to make the governing equations closed, complete and compatible, six processes and their coupling effects were considered, including stress-strain, water flow, gas flow, vapor flow, heat transport and porosity evolution processes. The physical phenomena such as phase transition, gas solubility in liquid, thermo-osmosis, moisture transfer and moisture swelling were modeled. As a result, the relative humidity of pore gas was defined on a sounder physical basis, avoiding the traditional definition as a negative exponential function of suction and absolute temperature. By selecting displacements, pore water pressure, pore gas pressure, pore vapor pressure, temperature and porosity as basic unknown variables, a finite element formulation was then established, and a three-dimensional computer code, THYME3D, was developed, with each node of 8 degrees of freedom. The bentonite THM Mock-up experiments performed by CEA were employed to validate the mathematical model and the software. The main coupling mechanisms involved in the experiments were satisfactorily simulated in the validation, and the effects of the governing equations, the constitutive relations and the parameters on the coupled THM processes were understood. The work developed enabled further in-depth research on fully coupled THM or THMC processes in porous media.

  • 172. Chen, Y.F
    et al.
    Zhou, C.B
    Mao, X.Y
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Numerical simulation of coupled thermal elastic behaviors for hard rock pillar in Äspö Pillar Stability Experiment, Sweden2010In: Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering, ISSN 1000-4548, Vol. 32, no 8, p. 1200-1206Article in journal (Refereed)
    Abstract [en]

    The goal of the Äspö Pillar Stability Experiment performed in Äspö Hard Rock Laboratory, Sweden is to investigate the mechanical response and progressive failure process of ahard rock pillar during excavation and heating. Numerical simulation of the thermalelastic behaviors for the pillar is one of the three tasks of the DECOVALEX-2011 project. The evolutions of stress, deformation and temperature of the pillar are modeled by using a coupled thermal elasticity model. The research results demonstrate that the thermalelasticity model is suitable for describing the coupled thermal mechanical behaviors of the pillar during excavation and heating. The stress redistribution and temperature evolution processes of the pillar are largely modeled, and the failure process and its propagation are qualitatively analyzed. The major limitations of the thermal elasticity model are its absence of the multiphase flow and progressive failure processes. The model developed and the modeling experiences accumulated in this study may be helpful for the stability and safety assessment of the hard granite host rock in China's Beishan preselected area for high-level radioactive waste disposal.

  • 173. Chen, Yifeng
    et al.
    Zhou, Chuangbing
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Modeling coupled THM processes of geological porous media with multiphase flow: Theory and validation against laboratory and field scale experiments2009In: Computers and geotechnics, ISSN 0266-352X, E-ISSN 1873-7633, Vol. 36, no 8, p. 1308-1329Article in journal (Refereed)
    Abstract [en]

    A FEM model for analysis of fully coupled multiphase flow, thermal transport and stress/deformation in geological porous media was developed based on the momentum, mass and energy conservation laws of the continuum mechanics and the averaging approach of the mixture theory over a three phase (solid-liquid-gas) system. Six processes (i.e. stress-strain, water flow, gas flow, vapor flow, heat transport and porosity evolution processes) and their coupling effects are considered, which not only makes the problem well-defined, but renders the governing PDEs closed, complete. compact and compatible. Displacements, pore water pressure, pore gas pressure, pore vapor pressure, temperature and porosity are selected as basic unknowns. The physical phenomena such as phase transition, gas solubility in liquid, thermo-osmosis, moisture transfer and moisture swelling are modeled. As a result, the relative humidity and other related variables in porous media can be evaluated on a sounder physical basis. A three dimensional computer code, THYME3D, was developed, with eight degrees of freedom at each node. The laboratory CEA Mock-up test and the field scale FEBEX benchmark test on bentonite performance assessment for underground nuclear waste repositories were used to validate the numerical model and the software. The coupled THM behaviors of the bentonite barriers were satisfactorily simulated, and the effects and impacts of the governing equations, constitutive relations and property parameters on the coupled THM processes were understood in terms of more straightforward interpretation of physical processes at microscopic scale of the porous media. The work developed enables further in-depth research on fully coupled THM or THMC processes in porous media.

  • 174.
    Cheng, Hua
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Hydrodynamic control of retention in heterogeneous aquifers and fractured rock2005Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    In this thesis, fluid flow and solute transport in heterogeneous aquifers and particularly in frac-tured rock have been investigated using Lagrangian Stochastic Advective-Reaction (LaSAR) framework. The heterogeneity of the aquifer structure or fracture configuration, as well as the various reaction/retention processes have been considered in the modelling approach. Advection and retention processes are considered to be the dominant transport processes. Monte-Carlo simulation results for transport of nonreactive tracers in 2D generic heterogeneous aquifers indicate that the travel time τ can be well approximated by a lognormal distribution up to a relative high degree of heterogeneity of the aquifers. Comparison between the Monte-Carlo simulation results and the results of first-order approximation reveals that the analytical solutions of the statistical moments of τ are valid only when the variability of the aquifer properties is small. For reactive tracers, Monte-Carlo simulations have been conducted by accounting for spatial variability of both hydraulic conductivity and one sorption parameter simultaneously. The simulation results indicate that the reaction flow path μ is a nonlinear function of distance for shorter distance, linear function for longer distance, and also that μ and τ are well correlated over the considered parameter range. The parameter β, which is purely determined by the flow condi-tions, quantifies the hydrodynamic control of retention processes for transport of tracers in frac-tures. Numerical simulations have been performed to study the statistical properties of the pa-rameter β, travel time τ and flow rate Q in a single heterogeneous fracture and in a sequence of fractures. The results of Monte-Carlo simulations indicate that the parameter β and τ are corre-lated with a power-law relationship β ∼ τm. The correlation between β and the flow rate Q have also been studied and an inverse power-law relationship β ∼ Q-m is proposed. The establishment of these relationships provides a link between the parameter β and measurable parameters τ (or Q).

    The LaSAR approach has been applied for prediction, evaluation and interpretation of the results of a number of tracer tests (TRUE-1, TRUE Block Scale and TRUE Block Scale Continuation) conducted by SKB at the Äspö site for tracer transport in fractures. The breakthrough curves may be predicted reasonably well, provided that the retention parameters, boundary conditions and hydraulic properties of the domain are given. The evaluation of TRUE tests indicates that the retention occurs mainly in the rim zone on site characterization time scales, while on the per-formance assessment time scale, diffusion and sorption in the unaltered rock matrix are likely to become dominant retention mechanisms.

  • 175.
    Cheng, Hua
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Impact of internal heterogeneity for tracer transport in fractured rockManuscript (preprint) (Other (popular science, discussion, etc.))
  • 176.
    Cheng, Hua
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Evaluation of Colloid Transport Experiments in a Quarried Block2009In: SCIENTIFIC BASIS FOR NUCLEAR WASTE MANAGEMENT XXXII / [ed] Hyatt NC; Pickett DA; Rebak RB, 2009, Vol. 1124, p. 519-524Conference paper (Refereed)
    Abstract [en]

    Colloid tracer experiments were performed in a single, heterogeneous fracture contained in a quarried block (QB) under the configuration of dipole tracer tests. The experiments were first performed using bentonite and 100 nm latex colloids, as well as conservative tracer iodide and bromide, under conditions of different flow rates in order to identify the flow rates that favour colloid transport. The tracer experiments were later expanded to include experiments with different colloid sizes and longer transport distances. The aims of the present study are to identify the processes that affect colloid transport in the QB fracture and to estimate the retention parameters for the different sized colloids. We model the measured breakthrough curves (BTCs) using an advection-retention approach. The key feature of the advection-retention model is that advective transport and retention processes are related in a dynamic manner through the flow equation. Two Lagrangian random variables, tau and beta, that depend solely on flow conditions, control the retention processes. Here tau is the nonreactive travel time and beta is related to tau but also depends on the local aperture value. We assume the water residence time distribution g(tau) to be inverse-gaussian. The first two moments of g(tau) were obtained by calibrating the measured BTCs of conservative tracers. We then model the colloid BTCs using g(tau) and take into account the retention processes. The modelling results indicate that dominating retention processes include first-order linear kinetic attachment/detachment on the fracture surface, and mass loss (removal) by filtration/sedimentation. Diffusion into the rock matrix is of a much lesser importance.

  • 177. Chijimatsu, M.
    et al.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Engineering Geology and Geophysics.
    Millard, A.
    Nguyen, T. S.
    Rejeb, A.
    Rutqvist, Jonny
    KTH, Superseded Departments, Land and Water Resources Engineering.
    Souley, M.
    Sugita, Y.
    Building Confidence in the Mathematical Models by Calibration With A T-H-M Field Experiment2004In: Coupled Thermo-Hydro-Mechanical-Chemical Processes in Geo-Systems — Fundamentals, Modelling, Experiments and Applications, Elsevier, 2004, no C, p. 193-198Chapter in book (Refereed)
    Abstract [en]

    Geological disposal of nuclear fuel wastes relies on the concept of multiple barrier systems. In order to predict the performance of these barriers, mathematical models have been developed, verified and validated against analytical solutions, laboratory tests and field experiments within the international DECOVALEX project. These models in general consider the full coupling of thermal (T), hydrological (H) and mechanical (M) processes that would prevail in the geological media around the repository. This paper shows the process of building confidence in the mathematical models by calibration with a reference T-H-M experiment with realistic rock mass conditions and bentonite properties and measured outputs of thermal, hydraulic and mechanical variables.

  • 178. Chijimatsu, M.
    et al.
    Nguyen, T. S.
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    De Jonge, J.
    Kohlmeier, M.
    Millard, A.
    Rejeb, A.
    Rutqvist, J.
    Souley, M.
    Sugita, Y.
    Numerical study of the THM effects on the near-field safety of a hypothetical nuclear waste repository - BMT1 of the DECOVALEX III project. Part 1: Conceptualization and characterization of the problems and summary of results2005In: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 42, no 5-6, p. 720-730Article in journal (Refereed)
    Abstract [en]

    Geological disposal of the spent nuclear fuel often uses the concept of multiple barrier systems. In order to predict the performance of these barriers, mathematical models have been developed, verified and validated against analytical solutions, laboratory tests and field experiments within the international DECOVALEX III project. These models in general consider the full coupling of thermal (T), hydraulic (H) and mechanical (M) processes that would prevail in the geological media around the repository. For Bench Mark Test no. 1 (BMTI) of the DECOVALEX III project, seven multinational research teams studied the implications of coupled THM processes on the safety of a hypothetical nuclear waste repository at the near-field and are presented in three accompanying papers in this issue. This paper is the first of the three companion papers, which provides the conceptualization and characterization of the BMT1 as well as some general conclusions based on the findings of the numerical studies. It also shows the process of building confidence in the mathematical models by calibration with a reference T-H-M experiment with realistic rock mass conditions and bentonite properties and measured outputs of thermal, hydraulic and mechanical variables.

  • 179. Chijimatsu, Masakazu
    et al.
    Borgesson, Lenart
    Fujita, Tomoo
    Jussila, Petri
    Nguyen, Son
    Rutqvist, Jonny
    Jing, Lanru
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    Model development and calibration for the coupled thermal, hydraulic and mechanical phenomena of the bentonite2009In: Environmental Geology, ISSN 0943-0105, E-ISSN 1432-0495, Vol. 57, no 6, p. 1255-1261Article in journal (Refereed)
    Abstract [en]

    In the international DECOVALEX-THMC project, five research teams study the influence of thermal-hydro-mechanical (THM) coupling on the safety of a hypothetical geological repository for spent fuel. In order to improve the analyses, the teams calibrated their bentonite models with results from laboratory experiments, including swelling pressure tests, water uptake tests, thermally gradient tests, and the CEA mock-up THM experiment. This paper describes the mathematical models used by the teams, and compares the results of their calibrations with the experimental data.

  • 180.
    Choga, Faith
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Management and Assessment.
    Post-EIA monitoring and WebTAG objectives: A review of selected road projects in UK.2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Roads are an important part of the infrastructure of any country, as they facilitate the transportation of goods and people. The UK has got a good road network but has a low motorway density compared to other European countries. The High-ways Agency has a programme to improve the road network, mainly to ease con-gestion. To ensure the sustainability of road projects the UK government has set guidelines and standards that have to be met. These are the criteria used to ap-praise road projects for which EIA is a significant input. This paper seeks to find the connection between the transport appraisal objectives and post-EIA monitor-ing. The study was carried out by reviewing EIS and CEMP documents of three road projects in England. A short questionnaire with open questions was also ad-ministered. The results show that monitoring of impacts associated with the re-spective projects was mainly proposed during the construction phase, and for en-vironmental impacts. Social and economic impacts are generally not monitored during and after construction. Whilst post-EIA monitoring of impacts is seldom carried out, monitoring depends on the type of project, construction involved and the location of the project. More research is required in different kinds of projects, and more needs to be done to enforce ongoing monitoring after the EIA to sup-port the POPE exercise.

  • 181. Christiansen, J. R.
    et al.
    Elberling, B.
    Jansson, Per-Erik.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Modelling water balance and nitrate leaching in temperate Norway spruce and beech forests located on the same soil type with the CoupModel2006In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 237, no 03-jan, p. 545-556Article in journal (Refereed)
    Abstract [en]

    Two contrasting forest ecosystems located in close proximity to each other were selected for evaluating the importance of tree species and afforestation in relation to the water balance and the quality of the water leaving the forest root zone. Measurements included soil water content and the collection of precipitation, canopy throughfall, stem flow and soil solution on a weekly basis during 15 months (1999-2000). Soil solutions were extracted using suction probes installed at all major horizons within the upper 120 cm of a Norway spruce (N. spruce) stand (Picea Abies [L.] Karst.) and a European beech stand (Fagus Sylvatica L.) located on the same soil type. Soil solutions were analyzed for the content of all major ions, including nitrate. A water balance model (CoupModel) was used to estimate percolation rates beneath the root zone. Percolation at the beech stand was 292 mm and only 41 rnm at the N. spruce stand mainly due to differences in the interception loss. The highest annual leaching of Mg, K, Na, Al, Cl, SO4-S was noted in the N. spruce stand while leaching of NO3-N was highest in the beech stand, corresponding to 39 kg ha(-1) year(-1). By contrast, the annual leaching of NO3-N in the N. spruce stand was only 0.5 kg ha(-1) year(-1). The larger amount of NO3-N was leaving the beech forest soil despite the fact that the N. spruce stand had the highest atmospheric N-deposition. Thus, differences in NO3-N leaching between the stands must be related to differences in uptake and accumulation of N in the vegetation and within the upper 120 cm of the soil. Differences in the water balance and NO3-N leaching between beech and N. spruce stands call for further attention to the selection of tree-species on a soil type basis when planning future afforestation projects, particularly when such projects aim to improve the quality of water infiltrating to the groundwater zone.

  • 182. Chuang, T.C
    et al.
    Henkel, Herbert
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Engineering Geology and Geophysics.
    GIS Visualization of Complex Geoscientific Data from the Björkö Structure2006In: GeoCongress 2006: Geotechnical Engineering in the Information Technology Age, Atlanta: American Society of Civil Engineers (ASCE), 2006, 2, , p. 204-209p. 204-209Conference paper (Refereed)
    Abstract [en]

    Based on the idea of Scientific Visualization, this research is aimed to visualize the complex geoscientific data to support the mapping work of the Björkö Energy Project, which has an ultimate goal to place a heat exchanging mechanism at the most suitable location in the subsurface. The production from this impact crater structure is expecting to supply the heating use for the great Stockholm area. The various point data types were compiled to diverse maps according to their characteristics. Several GIS and numerical tools are introduced integratedly to accomplish the work. The research in addition helps to streamline the data and maps processing activities carried out by the varied working groups

  • 183. Claudio, P.
    et al.
    Von Brömssen, Mattias
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Claus, K.
    Møller, M. L.
    Marco, P.
    Umberto, M.
    Geochemical modelling application for a 1-d arsenic reactive transport study in alluvial aquifers, Matlab Upazila, Bangladesh2009In: Rendiconti Online Societa Geologica Italiana, ISSN 2035-8008, Vol. 6, p. 364-365Article in journal (Refereed)
    Abstract [en]

    Mechanistic modelling was used to investigate the hydrochemical evolution along a vertical column, should cross-contamination occur. 1-D reactive transport was carried out to assess sorption effects on aqueous/solid arsenic distribution in Matlab Upazila, Bangladesh. Thermodynamic relationships between aqueous ions and aquifer materials have been investigated: comparison between redox couples shows electrochemical disequilibrium; sorption mainly occurs on weak and strong Hydrous Ferric-Oxides, described by the Surface Complexation Mode. The basis for reactive transport calculations is given by a static model, that evaluates the competing ions net effect: they reduce by ca. 50% arsenic bounding. Desorption process alone can give unacceptable As (aq) concentrations, starting from only a few mg/kg As (sorb). Redox zonation was the starting point for the model conception, which allowed calculating the contamination evolution in an oxidising As-low aquifer. Groundwater analysis is worked out for a 20 cells column of aquifer material, whose top represents the upper reducing aquifer, the bottom the oxidising aquifer; contamination takes place through an As-rich solution percolating into the column. Results are a function of the flow velocity, that needs to be carefully defined before further modelling.

  • 184.
    Coello Midence Balthasar, Zairis Aida
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Management.
    Insufficient water supply in an urban area - case study: Tegucigalpa, Honduras2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Tegucigalpa, the capital of Honduras, has experienced an unsatisfied water demand during the last three decades. The state owned water utility in charge of the water supply of the country, SANAA, has faced this deficit by providing an intermittent water supply. The intermittent water supply has increased the gap between the rich and the poor, who cannot afford water storage facilities. Theories explain water scarcity either by low precipitation or by lack of investment in water structures. This thesis investigates the applicability of both explanations by quantifying the annual precipitation in the sub catchments with water supply potential for Tegucigalpa, and identifying the problems which caused the lack of investment into the water infrastructure. The analysis concluded that even if the annual precipitation is abundant, it is not evenly distributed in time and in space. Furthermore, it is argued that the financial limitations which hindered the lack of investment in water structures originated in the low tariffs imposed, and to the practices of the patronage system.

  • 185.
    Coello Midence Balthasar, Zairis Aida
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water Management.
    Balfors, Berit
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Management and Assessment.
    Problems faced by a national water utility in an urban area, a case study: Tegucigalpa, Honduras2011In: Water Resources Managemtn 2011, Riverside, California, USA, 2011Conference paper (Refereed)
  • 186.
    Coello-Balthasar, Zairis
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Balfors, Berit
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Problems faced by a national water utility in an urban area, case study: Tegucigalpa, Honduras2013In: International Journal of Sustainable Development and Planning, ISSN 1743-7601, E-ISSN 1743-761X, Vol. 8, no 4, p. 508-522Article in journal (Refereed)
    Abstract [en]

    The capital of Honduras, Tegucigalpa, has suffered a shortage of piped water, since the 1980s. The national utility company in charge of supply, SANAA, opted to supply water intermittently, which poses a problem for the population who cannot afford water storage facilities. Interviews were conducted with the various authorities involved in the water sector to reveal why SANAA has not been able to incorporate new sources of water and therefore satisfy the needs of the growing population. The research revealed that SANAA's operations have been hindered by the fast and unorganized growth of the city, the failure of other governmental agencies to comply with their mission efficiently, and also by the intervention of the Central Government in its operations. Stability of SANAA's management and coordination between governmental agencies are essential for the efficient operation and long-term planning of and investment in the water sector.

  • 187.
    Coello-Balthasar, Zairis
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Management and Assessment.
    Phumpiu, Patricia
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water Management.
    Balfors, Berit
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Environmental Management and Assessment.
    Gustafsson, Jan-Erik
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630), Water Management.
    Assessment of causes leading to an insufficient water supply in Tegucigalpa, Honduras2011In: WIT Transactions on Ecology and the Environment, ISSN 1743-3541, Vol. 145, p. 27-38Article in journal (Refereed)
  • 188. Corell, Hanna
    et al.
    Moksnes, Per-Olav
    Engqvist, Anders
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Döös, Kristofer
    Jonsson, Per R.
    Depth distribution of larvae critically affects their dispersal and the efficiency of marine protected areas2012In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 467, p. 29-46Article in journal (Refereed)
    Abstract [en]

    This study aims to improve estimates of dispersal by including information on larval traits, and in particular to explore how larval depth distribution affects connectivity and MPA (marine protected area) functionality in the Baltic Sea. A field survey showed that both invertebrates and fish differed in their larval depth distribution, ranging from surface waters to >100 m. A biophysical model of larval dispersal in the Baltic Sea showed that decreased depth distribution increased average dispersal distance 2.5-fold, decreased coastal retention and local recruitment, and substantially increased connectivity. Together with pelagic larval duration (PLD), depth distribution explained 80% of total variation in dispersal distance, whereas spawning season, and geographic and annual variations in circulation had only marginal effects. Median dispersal distances varied between 8 and 46 km, with 10% of simulated trajectories dispersing 30 to 160 km depending on drift depth and PLD. In the Baltic Sea, the majority of shallow Natura 2000 MPAs are <8 km in diameter. In the present study, only 1 of the 11 assessed larval taxa would have a recruitment >10% within MPAs of this size. Connectivity between MPAs was expected to be low for most larval trait combinations. Our simulations and the empirical data suggest that the MPA size within the Natura 2000 system is considerably below what is required for local recruitment of most sessile invertebrates and sedentary fish. Future designs of MPA networks would benefit from spatially explicit biophysical models that consider dispersal and connectivity for complex circulation patterns and informed larval traits.

  • 189.
    Cucarella Cabañas, Victor
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Phosphorus recycling from wastewater to agriculture using reactive filter media2007Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    This thesis focused on testing the suitability of reactive filter media used for phosphorus (P) removal from wastewater as fertilizers, thus recycling P to agriculture. The work compared the P sorption capacity of several materials in order to assess their suitability as a source of P for plants. The selected materials (Filtra P, Polonite and wollastonite) were saturated with P and used as soil amendments in a pot experiment. The amendments tended to improve the yield of barley and ryegrass compared with no P addition. The amendments also increased soil pH, P availability and cation exchange capacity in the studied soils. The substrates studied here can be of particular interest for acid soils. Of the materials studied, Polonite appears to be the most suitable substrate for the recycling of P from wastewater to agriculture

  • 190.
    Cucarella Cabañas, Victor
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Recycling Filter Substrates used for Phosphorus Removal from Wastewater as Soil Amendments2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis studied the viability of recycling filter substrates as soil amendments after being used in on-site systems for phosphorus (P) removal from wastewater. Focus was put on the materials Filtra P and Polonite, which are commercial products used in compact filters in Sweden. A prerequisite for this choice was to review filter materials and P sorption capacity. The filter substrates (Filtra P, Polonite and wollastonite tailings) were recycled from laboratory infiltration columns as soil amendments to a neutral agricultural soil and to an acid meadow soil to study their impacts on soil properties and yield of barley and ryegrass. The amendments tended to improve the yield and showed a liming effect, significantly increasing soil pH and the availability of P. In another experiment, samples of Filtra P and Polonite were equilibrated in batch experiments with the two soils in order to study the P dynamics in the soil-substrate system.  Batch equilibrations confirmed the liming potential of Filtra P and Polonite and showed that improved P availability in soils was strongly dependent on substrate P concentration, phase of sorbed P, and soil type. Finally, samples of Polonite used for household wastewater treatment were recycled as soil amendments to a mountain meadow and to an agricultural field for wheat cropping. The liming effect of Polonite was confirmed under field conditions and the results were similar to those of lime for the mountain meadow soil. However, the results were quite different for the agricultural field, where Polonite did not affect soil pH or any other chemical and physical soil properties investigated and had no impact on wheat yield and quality. The results from field experiments suggested that Polonite can be safely recycled to meadows and cropping fields at rates of 5-10 ton ha-1 but long-term studies are needed to forecast the effects of accumulation.

  • 191.
    Cucarella, Victor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Mazurek, Ryszard
    Zaleski, Tomasz
    Kopec, Michal
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Effect of Polonite used for phosphorus removal from wastewater on soil properties and fertility of a mountain meadow2009In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 157, no 7, p. 2147-2152Article in journal (Refereed)
    Abstract [en]

    Reactive filter materials used for phosphorus (P) removal from wastewater can be disposed of as soil amendments after treatment, thus recycling P and other macro- and micro-nutrients to plants. In addition, materials with a high pH and Ca content, such as Polonite, are potential soil conditioners which, can be particularly beneficial for acid soils. Polonite previously used for on-site wastewater treatment was applied as a soil amendment to a mountain meadow. The amendment significantly increased soil pH and decreased the hydrolytic acidity, thus reducing Al toxicity risks. The effects were comparable to those of liming. No difference in yield and P uptake by meadow plants was observed. The uptake of metals was lower for amended soils, especially the uptake of Mn. Using Polonite after wastewater treatment as a soil amendment is thus a viable disposal alternative that can replace liming, when necessary, being capable of recycling P and other nutrients to meadow plants.

  • 192.
    Cucarella, Victor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Phosphorus sorption capacity of filter materials used for on-site wastewater treatment determined in batch experiments – a comparative study2009In: Journal of Environmental Quality, ISSN 0047-2425, E-ISSN 1537-2537, Vol. 38, p. 381-392Article in journal (Refereed)
    Abstract [en]

    Increasing numbers of filter materials have been proposed as suitable media for P removal in on-site wastewater treatment systems. The phosphorus sorption capacity (PSC) of the material can be estimated in batch experiments and is commonly used as the criterion for material selection. However, there is no standard procedure and batch experimental parameters are arbitrarily established, thus leading to difficulties in comparing the results. The main parameters affecting the batch adsorption system are the form and amount of material, material-to-solution ratio, nature, pH and initial concentration of P solution, contact time, agitation, and temperature. This paper critically reviews a number of relevant studies that used batch experiments to estimate the PSC of different filter materials. The nature and form [if the materials vary significantly and there is broad variation in the batch experimental parameters set in the selected studies. Analysis of the data from selected studies showed a relationship between particle size or pH of the material and its PSC. The initial P concentration of the solution and the material-to-solution ratio in the batch system were found to be correlated with the estimated PSC suggesting that batch parameters have a great influence on the results. Based on the analysis of the selected studies, the difficulties Of using batch experiments are outlined, recommendations for batch experiment procedure ate suggested and a classification system for filter materials according to their PSC. and particle size is presented.

  • 193.
    Cucarella, Victor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Renman, Agnieszka
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Phosphorus sorption properties of soils amended with recycled wastewater filter substrates2009In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259Article in journal (Other academic)
  • 194.
    Cucarella, Victor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Zaleski, T.
    Mazurek, R.
    Recycling of calcium-silicate material after wastewater filtration to agriculture -Soil condition impact2012In: Ecological Chemistry and Engineering S, ISSN 1898-6196, Vol. 19, no 3, p. 373-382Article in journal (Refereed)
    Abstract [en]

    Reactive filter materials aimed at phosphorus (P) recovery is a novel method for on-site wastewater treatment. Once the bed filter is no longer effective, the sorbent must be replaced and can then be recycled as a soil amendment to agriculture. This study investigated the short-term effects of such amendments in a field with a wheat crop in order to evaluate the risks and/or potential benefits of this disposal option. The developed product Polonite (manufactured from Opoka) was used as a model filter sorbent in the field trial. Rates corresponding to approximately 6 and 8 tons per hectare were applied. In the short-term, this amending did not affect soil physical and sorption properties. The rate of Polonite used here, as P source for wheat was irrelevant in this kind of soil. The usefulness of this disposal option of exhausted filter material is discussed.

  • 195.
    Cucarella, Victor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Zaleski, Tomasz
    Department of Soil Science and Soil Protection, Agricultural University of Cracow, Poland.
    Mazurek, Ryszard
    Department of Soil Science and Soil Protection, Agricultural University of Cracow, Poland.
    Phosphorus sorption capacity of different types of opoka2007In: Annals of Warsaw University of Life Sciences – SGGW Land Reclamation, ISSN 1898-8857, Vol. 38, p. 11-18Article in journal (Refereed)
    Abstract [en]

    Phosphorus sorption capacity ofdifferent types of opoka. The bedrock opoka hasbeen lately reported as an appropriate reactivemedia for onsite wastewater treatment systemsdue to its high phosphorus (P) sorption capacity.However, variations on its chemical compositionmay affect its reactivity with P, therefore leadingto a variable P removal effi ciency. In this paper,the P-sorption capacity of three different typesof opoka from the region of Miechów, Poland,is reported. According to the silica and carbonatecontent, opoka samples were classifi ed as light--weight and heavy-weight opoka. When heatedover 900°C, opoka showed a very high P-sorptioncapacity that was well correlated to its Ca content.P-sorption isotherms from batch experiments withan artifi cial P solution were plotted and fi tted tothe Langmuir and Freundlich adsorption models.The Freundlich isotherm appeared to model betterthe P-sorption of light opoka and the Langmuirisotherm of heavy opoka, suggesting differentdominating mechanisms of P-sorption by lightand heavy opoka.

  • 196.
    Cucarella, Victor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Zaleski, Tomasz
    Department of Soil Science and Soil Protection, Agricultural University of Cracow.
    Mazurek, Ryszard
    Department of Soil Science and Soil Protection, Agricultural University of Cracow.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering.
    Effect of reactive substrates used for phosphorus removal from wastewater on the feritlity of acid soils2008In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 99, no 10, p. 4308-4314Article in journal (Refereed)
    Abstract [en]

    Reactive substrates used in filter systems can reduce phosphorus (P) pollution and, once saturated with P, may be recycled in agriculture. These substrates are usually calcium carbonate derivates with high pH values, which may be particularly beneficial for acid soils. Three reactive substrates (Filtra P, Polonite and wollastonite) saturated with P were used as amendments to an acid soil in a pot experiment. Substrate amendments tended to improve ryegrass yield and P uptake compared with control and potassium phosphate treatments. Polonite produced the highest yield/amendment ratio, while Polonite and Filtra P significantly increased the concentrations of P and Ca in the ryegrass. Addition of all three substrates increased the pH, AL-extractable P and cation exchange capacity of soils during the experiment. These substrates can therefore be applied to acid soils in order to recycle P and improve soil properties.

  • 197.
    Cucarella, Victor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Zaleski, Tomasz
    Department of Soil Science and Soil Protection, Agricultural University of Krakow.
    Mazurek, Ryszard
    Department of Soil Science and Soil Protection, Agricultural University of Krakow.
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Fertilizer potential of calcium-rich substrates used for phosphorus removal from wastewater2007In: Polish Journal of Environmental Studies, ISSN 1230-1485, E-ISSN 2083-5906, Vol. 16, no 6, p. 817-822Article in journal (Refereed)
    Abstract [en]

    Phosphorus (P) in wastewater is an important source of pollution, but properly managed, it can become a resource. Reactive filter media with a high affinity for P are promising in reducing P from effluents allowing nutrient recycling. In this study, three calcium-rich substrates (Filtra P, Polonite, wollastonite) with ability to remove P from wastewater have been saturated with P and tested as potential fertilizers in a pot experiment. Polonite had a relatively higher P content than Filtra P and wollastonite after saturation. All three materials tended to improve the yield of barley compared with the control treatment. Polonite induced the highest yield per unit of amendment from all three materials due to its higher P content, which could be shown in a higher ammonium lactate (AL)-extractable P in soil after harvesting. The application of the substrates slightly increased soil pH and decreased the hydrolytic acidity.

  • 198.
    Cucarella, Victor
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Zaleski, Tomasz
    Mazurek, Ryszard
    Renman, Gunno
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Geochemistry and Ecotechnology.
    Recycling Polonite used for on-site wastewater treatment as a soil amendment to a wheat cropping field2009Article in journal (Other academic)
  • 199.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    A general memory function for modeling mass transfer in groundwater transport2012In: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 48, p. W04528-Article in journal (Refereed)
    Abstract [en]

    A power-law extension of the gamma distribution is proposed as a general memory function for capturing rate limitations of retention in groundwater transport. Using moments, we show how the new memory function can be reduced to most other forms available in the literature, exactly or approximately. The proposed formulation is suitable for field scale or laboratory scale transport modeling. Rate limitation effects are illustrated for solute transport by considering the fractional mass release over a given transport scale. The equilibrium and no-retention cases set bounds for contaminant attenuation, between which the impact of rate limitations is clearly exposed.

  • 200.
    Cvetkovic, Vladimir
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Water Resources Engineering.
    Diffusion-controlled tracer retention in crystalline rock on the field scale2010In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 37, p. L13401-Article in journal (Refereed)
    Abstract [en]

    Tracer retention is a key process for the barrier function of crystalline rock to any contaminant. Here we investigate the nature of retention mechanisms and their field-scale parametrization using results of a comprehensive tracer transport experiment in crystalline rock on the field scale (Aspo Hard Rock Laboratory, Sweden). A method for identifying dominant retention mechanisms and inferring key parameters on the site scale is presented. Taking advantage of multiple tracer tests with a wide range of sorption affinities, retention is shown to be diffusion-controlled. For the considered site, robust features of tracer migration can be reasonably well predicted within a rock volume on at least 200 m scale, by combining independent information with a simple model.

1234567 151 - 200 of 1279
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