Laboratory determination of longitudinal dispersion in soil : master's thesis

Ovaj rad rezultat je ispomoći u laboratoriju dipl. ing. Stanku Ružičiću pri izradi njegove disertacije u sklopu FP7 projekta GENESIS (Groundwater and Dependent Ecosystems: New Scientific and Technological Basis for Assessing Climate Change and Land-use Impacts on Groundwater). Predmet istraživanja ovog rada je longitudinalna disperzija u tlu. Cilj je utvrđivanje parametra toka (hidraulička vodljivost) i transporta onečišćivala (longitudinalna disperzija) na koloni tla u laboratoriju. Eksperiment određivanja longitudinalne disperzije proveden je primjenjujući konzervativni traser kalcijev-klorid (CaCl2) na porušenim uzorcima iz dva različita horizonta tla s lokacije Kosnica na području Zagrebačkog vodonosnika. Na temelju provedenog eksperimenta inverzno su modelirani parametri saturirana hidraulička vodljivost (Ks) i longitudinalna disperzija (DL) u tlu uz pomoć HYDRUS 1-D računalnog programa. Za uzorak prahovito ilovastog tla porjeklom iz AC-IC horizonta dobivena je vrijednost saturirane hidrauličke vodljivosti u iznosu od 0,01 cm/min, te longitudinalne disperzije (DL) u iznosu od 1,02 cm. Za uzorak pjeskovito ilovastog tla iz horizonta IIC/Gso dobivena vrijednost saturirane hidrauličke vodljivosti bila je 0,04 cm/min te longitudinalne disperzije 1,72 cm. Rezultati dobiveni laboratorijskim eksperimentom i inverznom procjenom parametara saturirane hidrauličke vodljivosti i longitudinalne disperzije, mogu poslužiti u svrhu stvaranja temeljnih pretpostavki o mogućem transportu onečišćivala kroz tlo do podzemne vode.Abstract: This master’s thesis is a result of assistance in laboratory work to MSc. Stanko Ružičić in preparing his PhD thesis under the FP7 project GENESIS (Groundwater and Dependent Ecosystems: New Scientific and Technological Basis for Assessing Climate Change and Land-use Impacts on Groundwater). The subject of this research is longitudinal dispersion in soil. The aim is to determine the parameters of flow (hydraulic conductivity) and transport of contaminants (longitudinal dispersion) on the soil column in the laboratory. The longitudinal dispersion experiment was conducted using a conservative tracer calcium chloride (CaCl2) on samples taken from two different soil horizons at the Kosnica site above Zagreb aquifer system. Based on the experiment, saturated hydraulic conductivity (Ks) and longitudinal dispersion (DL) were inversely modeled using HYDRUS 1-D software. For the sample of silty loam soil originating from the AC-IC horizon, the value obtained for the saturated hydraulic conductivity was 0.01 cm/min, while the value obtained for the longitudinal dispersion was 1.02 cm. For the sample of sandy loam soil originating from IIC/GSO horizon, the value obtained for the saturated hydraulic conductivity was 0.04 cm/min, while the value obtained for the longitudinal dispersion was 1.72 cm. The results of the laboratory experiment and inverse parameter estimation can be used as the basis for assessment of contamination risk for groundwater