diplomska naloga
Urška Martinčič (Author), Dušan Žagar (Mentor), Boris Kompare (Thesis defence commission member), Jože Panjan (Thesis defence commission member), Mario Krzyk (Thesis defence commission member), Matjaž Četina (Co-mentor)

Abstract

Modeliranje izmenjave živega srebra med sedimentom in vodo v Tržaškem zalivu

Keywords

gradbeništvo;diplomska dela;UNI;VKI;živo srebro;izmenjava;sediment;model PCFLOW3D;difuzijski tokovi;Tržaški zaliv;

Data

Language: Slovenian
Year of publishing:
Source: Ljubljana
Typology: 2.11 - Undergraduate Thesis
Organization: UL FGG - Faculty of Civil and Geodetic Engineering
Publisher: [U. Martinčič]
UDC: 543.3(497.4 Trst)(043.2)
COBISS: 5540961 Link will open in a new window
Views: 1817
Downloads: 500
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Other data

Secondary language: English
Secondary title: Modelling of mercury exchange between sediment and water in the Gulf of Trieste
Secondary abstract: The present work focuses on modelling of mercury exchange between sediment and water due to diffusion using three-dimensional nonlinear unsteady-state baroclinic mathematical model PCFLOW3D. The PCFLOW3D model was upgraded with the equations for determining the diffusion fluxes of mercury between sediment and water on the basis of concentrations in sediment pore waters and in the overlying water. The performed model verification showed a good agreement between the results of simulations and the test calculations in Excel. In the performed sensitivity analysis the impact of all relevant parameters in the exchange equations (diffusion coefficient, sediment porosity, Hg concentrations in sediment and water, thickness of active sediment layer, and thickness of contaminated sediment) was evaluated. The results showed that for accurate simulations each individual parameter has to be chosen correctly. The model was further used for simulations in the Gulf of Trieste, which, due to the lack of reliable input data only serve as an additional test of the model and do not represent the real situation. The performed simulations took into account 5, 10, 30 and 90 day time intervals, separately for summer and winter conditions. The results of simulations were compared to measurements in the Gulf of Trieste described in Covelli et al. (1999). The achieved agreement was within an order of magnitude. The quantity of mercury removed from the sediment within one year was further determined from simulations. The agreement within a factor of four was achieved with the published results. The described approach of determining sediment-water diffusion fluxes was used in the PCFLOW3D model for the first time. With additional quality input data this approach will enable the improvement of the modelling results and better understanding of the mercury cycle in coastal seas.
Secondary keywords: graduation thesis;mercury;exchange;sediment;model PCFLOW3D;diffusion fluxes;Gulf of Trieste;
File type: application/pdf
Type (COBISS): Undergraduate thesis
Thesis comment: Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo
Pages: XVI, 93 str.
Type (ePrints): thesis
Title (ePrints): Modelling of mercury exchange between sediment and water in the gulf of Trieste
Keywords (ePrints): živo srebro;izmenjava;sediment;model PCFLOW3D;difuzijski tokovi;Tržaški zaliv
Keywords (ePrints, secondary language): mercury;exchange;sediment;model PCFLOW3D;diffusion fluxes;Gulf of Trieste
Abstract (ePrints): Diplomsko delo obravnava modeliranje izmenjave živega srebra med sedimentom in vodo zaradi difuzije s tridimenzionalnim nestacionarnim nelinearnim baroklinim matematičnim modelom PCFLOW3D. Za potrebe modeliranja je bil model nadgrajen z enačbami za določanje difuzijskih tokov živega srebra med sedimentom in vodo na osnovi koncentracij v pornih vodah sedimenta in sloju vode ob dnu. Opravljena je bila verifikacija modela, rezultati simulacij so se dobro ujemali s kontrolnimi izračuni v Excelu. Izvedena je bila občutljivostna analiza, pri čemer je bil ovrednoten vpliv vseh pomembnih parametrov, ki jih vsebujejo enačbe izmenjave (difuzijski koeficient, poroznost sedimenta, koncentracije Hg v sedimentu in vodi, debelina aktivnega sloja sedimenta in debelina kontaminiranega sedimenta). Pri tem je bilo ugotovljeno, da je za točnost računa pomembna pravilna izbira vsakega posameznega parametra. Model je bil uporabljen tudi za simulacije v Tržaškem zalivu, ki pa so zaradi pomanjkljivih podatkov služile le kot dodaten preizkus modela in ne predstavljajo realnega stanja. Simulacije so bile izvedene za obdobja 5-ih, 10-ih, 30-ih in 90-ih dni za poletne in zimske razmere. Izvedena je bila primerjava rezultatov simulacij z meritvami v Tržaškem zalivu, ki so jih opravili Covelli in sod. (1999), pri čemer je bilo dosežno ujemanje v okviru istega velikostnega razreda. Z modelom izračunana količina živega srebra, ki se z difuzijskimi tokovi v enem letu izloči iz sedimenta, se z rezultati, objavljenimi v literaturi, ujema v okviru faktorja štiri. V diplomski nalogi opisan princip določanja difuzijskih tokov med sedimentom in vodo je bil pri modelu PCFLOW3D uporabljen prvič in ob kvalitetnih vhodnih podatkih predstavlja način za izboljšanje rezultatov modeliranja in korak k boljšemu razumevanju cikla živega srebra v priobalnem morju.
Abstract (ePrints, secondary language): The present work focuses on modelling of mercury exchange between sediment and water due to diffusion using three-dimensional nonlinear unsteady-state baroclinic mathematical model PCFLOW3D. The PCFLOW3D model was upgraded with the equations for determining the diffusion fluxes of mercury between sediment and water on the basis of concentrations in sediment pore waters and in the overlying water. The performed model verification showed a good agreement between the results of simulations and the test calculations in Excel. In the performed sensitivity analysis the impact of all relevant parameters in the exchange equations (diffusion coefficient, sediment porosity, Hg concentrations in sediment and water, thickness of active sediment layer, and thickness of contaminated sediment) was evaluated. The results showed that for accurate simulations each individual parameter has to be chosen correctly. The model was further used for simulations in the Gulf of Trieste, which, due to the lack of reliable input data only serve as an additional test of the model and do not represent the real situation. The performed simulations took into account 5, 10, 30 and 90 day time intervals, separately for summer and winter conditions. The results of simulations were compared to measurements in the Gulf of Trieste described in Covelli et al. (1999). The achieved agreement was within an order of magnitude. The quantity of mercury removed from the sediment within one year was further determined from simulations. The agreement within a factor of four was achieved with the published results. The described approach of determining sediment-water diffusion fluxes was used in the PCFLOW3D model for the first time. With additional quality input data this approach will enable the improvement of the modelling results and better understanding of the mercury cycle in coastal seas.
Keywords (ePrints, secondary language): mercury;exchange;sediment;model PCFLOW3D;diffusion fluxes;Gulf of Trieste
ID: 8312091