The electrocoagulation/advanced oxidation treatment of the groundwater used for human consumption

The purpose of this work was development and application of the purification system suitable for the treatment of groundwater used for human consumption, satisfying following criteria: (a) no need for external addition of the chemicals; (b) simultaneous removal of wide range of contaminants present in the treated water; (c) low sensitivity to the changes in the composition of the treated water; (d) high quality of treated water with regards to all measured parameters. Therefore the well water from the 60 m deep water layer situated near the city of Osijek (Eastern Croatia) with elevated values of heavy metals, color, turbidity, suspended solids, ammonia and organic contaminants was processed. Due to the complex composition of the treated water, the purification system required the combination of electroreduction/electrocoagulation, using iron and aluminum electrode plates followed by the simultaneous ozonation/UV treatment. The electroreduction/electrocoagulation approach was used for the removal of heavy metals, suspended solids, color and turbidity, while the organic contaminants and ammonia were removed by the ozonation/UV treatment. All measured parameters in the purified water were significantly lower compared to the regulated values. Under the optimum treatment conditions, the removal efficiencies for color, turbidity, nickel and arsenic were 100%. The removal efficiencies of V, Cr, Mn, Fe, Cu, Zn, Pb, ammonia, fluorides, sulfates and COD were 94.5%, 96.0%, 98.3%, 99.6%, 99.7%, 97.8%, 96.7%, 96,7%, 93.4%, 51.4%, 72.2% and 93.8%, respectively, increasing with the increased initial concentrations.