Wastewater disinfection and organic matter removal using ferrate (VI) oxidation

The use of iron in a +6 valence state, (Fe (VI), as FeO4−2) was tested as a novel alternative for wastewater disinfection and decontamination. The removal of organic matter (OM) and index microorganisms present in an effluent of a wastewater plant was determined using FeO4−2 without any pH adjustment. It was observed that concentrations of FeO4−2 ranging between 5 and 14 mg l−1 inactivated up to 4-log of the index microorganisms (initial concentration c.a. 106 CFU/100 ml) and achieved OM removal up to almost 50%. The performance of FeO4−2 was compared with OM oxidation and disinfection using hypochlorite. It was observed that hypochlorite was less effective in OM oxidation and coliform inactivation than ferrate. Results of this work suggest that FeO4−2 could be an interesting oxidant able to deactivate pathogenic microorganisms in water with high OM content and readily oxidize organic matter without jeopardizing its efficiency on microorganism inactivation.