Sökning: "stagnant water zones"

Hittade 5 avhandlingar innehållade orden stagnant water zones.

  1. 1. Biogeochemical Processes in Denitrifying Woodchip Bioreactors and their Application in the Mining Industry

    Författare :Albin Nordström; Roger Herbert; Fritjof Fagerlund; Gunno Renman; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; water treatment; mine drainage; nitrate; nitrous oxide; DNRA; fermentation; syntrophy; temperature; kväverening; gruvvatten; nitrat; lustgas; DNRA; fermentation; syntrofi; temperatur; Hydrology; Hydrologi;

    Sammanfattning : This thesis evaluates passive denitrifying woodchip bioreactors (DWBs) for the removal of nitrate (NO3-) in neutral pH mine drainage, where water is passed through a carbon-rich porous matrix (e.g. woodchips) for the reduction of NO3- to nitrogen gas. LÄS MER

  3. 2. Solute Transport in Fractured Rocks : The Effect of Stagnant Water Zones and Velocity Dispersion

    Författare :Pirouz Shahkarami; Longcheng Liu; Ivars Neretnieks; Luis Moreno; Klaus-Peter Kröhn; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Channel network concept; radionuclide transport; stagnant water zones; velocity dispersion; modeling and simulation; Chemical Engineering; Kemiteknik;

    Sammanfattning : The focus of this thesis is on the development of new models to improve our understanding of radionuclide transport in the repository “far-field” in fractured rocks. The proposed models contribute to the channel network concept and describe the recently developed models with stagnant water zones (STWZs) and channels with variable aperture allowing to consider their possible impacts on the overall transport of radionuclides in fractured rocks. LÄS MER

  4. 3. Solute transport through fractured rocks : the influence of geological heterogeneities and stagnant water zones

    Författare :Batoul Mahmoudzadeh; Longcheng Liu; Ivars Neretnieks; David Hodgkinson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : To describe reactive solute transport and retardation through fractured rocks, three models are developed in the study with different focuses on the physical processes involved and different simplifications of the basic building block of the heterogeneous rock domain. The first model evaluates the effects of the heterogeneity of the rock matrix and the stagnant water zones in part of the fracture plane. LÄS MER

  5. 4. Mixing and Stagnation in Drinking Water Storage Tanks

    Författare :Ola Nordblom; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; storage tank; service reservoir; jet mixing; khappa - epsilon model; stagnation; tracer test; temperature measurement; thermal stratification; buoyant jets; CFD model;

    Sammanfattning : This thesis contributes to studies of the assessment of mixing conditions in drinking water storage tanks and analyses of parameters governing mixing rates and formation of stagnant zones. The work also contributes to a validation of Computational Fluid Dynamics (CFD) models of jet-forced mixing in storage tanks under neutral and thermally stratified conditions. LÄS MER

  7. 5. Solar radiation effects on decomposition and decomposers of plant litter in lakes

    Författare :Måns Denward; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; glucosidase; photo inhibition; photo oxidation; littoral; lakes; ergosterol; fungi; phragmites; bacteria; UV-B; Hydrobiology; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi;

    Sammanfattning : This thesis summarizes the results of a series of experiments, from test tube up to field study scale, performed to increase the understanding of solar radiation effects on decomposition and microbial decomposers of plant litter in stagnant water of littoral zones. In conclusion, I suggest that fungi play a significant role in the decomposition of plant litter submersed in lakes, and that their distribution is dependent on detritus quality and water chemistry, but also tends to be inversely related to the occurrence of bacteria attached to the litter. LÄS MER