Coagulation Enhanced with Adsorption and Ozonation Processes in Surface Water Treatment

Abstract

The requirements for water intended for domestic and economic purposes prompt the search for new solutions in surface water treatment technologies. In this study, the enhancement of coagulation processes by connections with adsorption and/or ozonation for surface water treatment was studied. The possibility of a reduction in natural organic matter (NOM) content in modified surface water was analysed regarding changes in colour, turbidity, oxidisability (OXI), total and dissolved organic carbon (TOC, DOC) and absorbance at 254 nm (UV254). Additionally, the changes in copper and zinc ion content during the modified surface water treatments studied were analysed for initial metal concentrations of 0.5 or 1.0 mg/L. Studies of modified surface water were carried out with doses of medium-basicity PAX coagulant (C2) 5 mg/L and PAC 100 mg/L. During the coagulation process, the colour decreased by 86–90%, turbidity by 85–90%, OXI by 65–77%, TOC by 65–76% and UV254 absorbance by 73–84%. The enhancement of coagulation with adsorption and/or ozonation resulted in an increased efficiency of colour and turbidity removal by 2 and 4%, respectively. The highest increase in efficiencies of OXI, TOC, DOC and UV254 removal, by 12, 12, 11 and 11%, was observed for the connection of ozonation with coagulation and adsorption. The efficiency of metal ion removal from modified water observed for the single coagulation process was 58 and 55% for copper and 46 and 43% for zinc, respectively, for initial concentrations of 0.5 and 1.0 mg/L. The intensification of coagulation with ozonation and adsorption resulted in metal removal on the level of 66 and 62% for copper and 62 and 54% for zinc.