Sökning: "Retention processes"

Visar resultat 6 - 10 av 172 avhandlingar innehållade orden Retention processes.

1. 6. Long-term metal retention processes in a peat bog : Field studies, data and modelling

   Författare :Kristina Syrovetnik; Ivars Neretnieks; Bert Allard; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Peat; heavy metals distribution; sequential extraction; binding mechanisms; modelling; metal sulphide oxidation; aqueous composition; sorption; humic substances; ferric oxyhydroxide; Chemical engineering; Kemiteknik;

   Sammanfattning : The study was inspired by the need to assess long-term metal retention in municipal solid waste (MSW) landfills. The long-term processes in landfills are poorly known due to the relatively short time that such landfills have been in existence. Natural analogues where similar metal binding processes could be expected were therefore sought for. LÄS MER

3. 7. Transport and Fate of Escherichia coli in Unsaturated Porous Media

   Författare :Emma Engström; Berit Balfors; Chin-Fu Tsang; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Contaminant transport modeling; Bacterial fate; Unsaturated zone; Retention; Straining; Escherichia coli;

   Sammanfattning : The unsaturated zone could provide an effective barrier against pathogenic microbes entering the groundwater. Knowledge relating to microbial fate in this zone is therefore important for increased understanding of groundwater vulnerability. LÄS MER

4. 8. Long-term development, modeling and management of nutrient loading to inland and coastal waters

   Författare :Amelie Darracq; Georgia Destouni; Andrea Rinaldo; Stockholms universitet; []
   Nyckelord :Nutrients; catchments; environmental management; climate change; population and lifestyle development; subsurface-surface water interactions; long-term simulations; nutrient retention; modeling; hydrology; transport processes; biogeochemistry; scaling; transport and reaction rates; Physical Geography; geografi med naturgeografisk inriktning;

   Sammanfattning : Environmental and water system protection and restoration require accurate knowledge and quantification of waterborne pollutant transport, retention-release and transformation processes taking place in the subsurface, river, lake and sea water systems, and at the interfaces between these systems. This thesis investigates the importance of spatial model resolution for such quantification and the possible long-term nutrient load development under different human perturbations and nutrient source management scenarios in the Swedish Norrström drainage basin, based on simulations with the GIS-based dynamic nutrient transport-attenuation model POLFLOW. LÄS MER

5. 9. Function and dynamics of woody debris in boreal forest streams

   Författare :Niklas Dahlström; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Boreal forest; CPOM; CWD; forest management; geomorphology; LWD; riparian forest; retention; residence time; streams; Sweden; woody debris; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : The work in this thesis deals with (1) the effects of woody debris on stream channel morphology and retention of organic material, and (2) the dynamics of woody debris and its relation to riparian forest history and composition. The studied stream reaches are situated in mature, productive forests in the boreal zone of Sweden. LÄS MER

7. 10. Effect of Hyporheic Exchange on Conservative and Reactive Solute Transport in Streams : Model Assessments Based on Tracer Tests

   Författare :Karin Jonsson; Anders Wörman; Bernhard H. Schmid; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; conservative; hyporheic exchange; model; reactive; retention; solute; sorption kinetics; stream transport; temporal moments; tracer experiment; Geovetenskap; Earth sciences; Geovetenskap; Sedimentology; sedimentologi;

   Sammanfattning : Understanding of the processes affecting solute transport in flowing water is important for the possibility to predict the evolution with time of polluted stream systems. This thesis presents tracer experiment methodology and model developments for solute transport in streams, with special focus on retention processes and their effect on solute stream transport. LÄS MER