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An analysis of the dynamics of the process of biochemical colmation of laterals of radial wells at the Belgrade groundwater source is presented. A very good correlation between the rate of forming of the colmations and the concentration of bivalent iron was obtained, on the basis of which the maximum recommended flows and velocities were defined, which are in good agreement with the values from previous articles and studies. The effects of regenerations on yield and the total volume of extracted water (up to 2 times higher than in the case of no regeneration) were investigated using a mathematical and software model. A correlation was developed linking the ratio of the amounts of water extracted with and without regeneration, to the aquifer hydraulic resistance, the coefficient of local hydraulic losses reduction due to regeneration, and the number of regenerations. The factor equal to the square root of the number of regenerations increased by one was added to the expressions for the maximum recommended values of inlet velocities and flows per lateral. The differences in flows and extracted volumes between operating modes with constant flow between regenerations and a constant, minimal water level were also examined using the model. The ratio between the total extracted volumes when the drawdown is kept equal to maximum and when the flow between the regenerations is kept constant reaches up to 1.25. [ABSTRACT FROM AUTHOR]

Study of the behavior and transport of pharmaceuticals in groundwater is significant for understanding the processes of natural attenuation and potential use of filtration through the aquifer to evaluate the most effective way to remove pharmaceuticals that occur under anthropogenic influence. This paper presents the results of a field experiment at the location of the drainage system of Kovin-Dubovac in Serbia, during which a tracer test was conducted and the behavior of selected pharmaceuticals (trimethoprim, carbamazepine, diclofenac and metamizole metabolite N-acetyl-4-aminoantipyrine (4-AAA)) was monitored. The objective of the paper is to show and analyze the results of the tracer test, during which the tracer NaCl was injected, and to correlate the obtained characteristics of the subsurface and the breakthrough curves of the selected pharmaceuticals, so that the effects of sorption can be quantified. During the tracer test, the hydraulic head, flow, electric conductivity and concentrations of the pharmaceuticals were monitored continuously to collect sufficient data. The results show that sorption coefficients can be determined from experimental data and the NaCl breakthrough curve. [ABSTRACT FROM AUTHOR]