driving force in the homogeneous flocculator with simultaneous PAC adsorption was lower than in the filter column. The filter showed a better utilization of PAC adsorption capacity than the volume system, for the optimal PAC dose. The authors proposed a new method where adsorption was carried out in the filter column with PAC applied to its upper layer. The powdered sorbent was applied to the bed at the end of a backwashing cycle. Two models of PAC adsorption in transient states for the homogeneous flocculator and the column mass exchanger were presented. The simulation calculations confirmed that there was still a possibility to double the PAC adsorption capacity concerning commonly used adsorption with coagulation in the homogeneous flocculator.

of equations for current and vorticity functions was solved. The distribution of pollutant concentrations in the river was calculated from a bidirectional advection and turbulent diffusion equation. Analysis of the distribution of concentrations leads to the conclusion that the effects of transverse advection associated with a lateral inflow of pollutants disappear relatively quickly. Therefore, the distribution of concentrations in cross sections further downstream from the point of pollutant discharge can be determined quite accurately just from an advection-diffusion model, with no transverse advection effects included. Such a level of accuracy is usually sufficient to assess the impact of a pollution source on the aquatic environment. The transverse mixing of pollutants in the stream proceeds slowly and creates a large mixing zone in which the concentrations of pollutants (low but still significant for water quality) can be detected in cross-sections that are remote from the pollutant discharge point. Transverse advection may be ignored while calculating concentrations in remote cross sections at straight watercourse sections and in steady state conditions.

process may require a linear combination of adsorption models running at different rates and at different parameters of adsorption isotherms. The model showed a good fit with the measured data and could be used in designing adsorption units at water or wastewater treatment plants. The proposed set of model equations enables to predict the effects of PAC adsorption in both plug flow reactors and homogeneous reactors.

wymagać liniowej kombinacji modeli adsorpcji działających z różnymi prędkościami i przy różnych parametrach izoterm adsorpcji. Model, na którym przeprowadzono badania, wpasował się w przykładowe dane, więc można go wykorzystać do projektowania jednostek adsorpcyjnych w oczyszczalniach wody lub ścieków. Proponowany zestaw równań modelowych pozwala przewidzieć skutki adsorpcji PAC zarówno w reaktorach z przepływem tłokowym, jak i reaktorach homogenicznych.

H2O2/m3/UV process. The process parameters were hydrogen peroxide doses 0.5–4.0 kg H2O2/m3, UV (254 nm) light intensity 75.5 W/m2 and irradiation time – 1 h. The oxidation efficiency varied broadly from 15 to 98% and higher COD values corresponded to lower oxidation efficiencies. The average hydrogen peroxide consumption per kg of COD w was = 12.2 g H2O2/m3/g O2 COD, while per TOC it was w′ = 69.0 g H2O2/m3/g C. The experiments enabled one to developed mathematical models for coagulation and oxidation kinetics. The models showed that at the initial COD = 859 g O2/m3, the coagulant dose of 100 g Al3+/m3, the hydrogen peroxide dose of 4 kg H2O2/m3 and the UV irradiation time of 3 h it is possible to decrease the COD by 98.4%.