Organic Matter and Heavy Metal Ions Removal from Surface Water in Processes of Oxidation with Ozone, UV Irradiation, Coagulation and Adsorption

Organic matter present in natural water is a serious problem during water treatment in terms of the possibility of creating disinfection by-products (DBP). The new materials and processes are still analyzed in order to improve the efficient removal of organic matter as well as other pollutants from water intended for human consumption. The aim of the presented study was to evaluate the efficiency of using various combined processes: (a) coagulation and adsorption, (b) oxidation with ozone and coagulation, (c) oxidation with ozone, coagulation and adsorption, and (d) oxidation with ozone, UV irradiation, coagulation and adsorption for treatment of the modified surface water. In the presented study, the changes in pH, turbidity, color, organic matter content (evaluated as oxidizability, total and dissolved organic carbon content, UV 254 and 272 absorbances), and Ni²⁺, Cd^2+, and Pb²⁺ ions content were determined during modified surface water purification. Supporting the coagulation process by adsorption with additional ozonation and UV irradiation of the water sample improved the treatment processes of modified surface water. Processes associated with coagulation increased the efficiency of removing color by 4–16% and reduced the value of UV₂₅₄ and UV₂₇₂ absorbance by 10–20%. Using ozonation did not significantly change the content of total organic matter. Heavy metal ions were mostly removed by coagulation and adsorption processes (40–60%). Including ozone, oxidation resulted in insignificant changes in the concentration of metal ions in the purified water (less than 5%). During the treatment of the tested, modified surface water, the best efficiency was observed after the use of coagulation and adsorption processes enhanced with ozone oxidation. The additional involvement of UV irradiation did not have a significant effect on the removal of the analyzed pollutants.