Feasibility of Wastewater Treatment with Ferrate

Iron (VI) ferrate, (FeO₄²^-), has been reported to have the potential to act as a coagulant and also a disinfectant in treating wastewater. This study investigates the effectiveness of potassium ferrate as both a coagulant and disinfectant for treating secondary effluent by means of a pilot-plant study. The units of the pilot plant included a flash-mix reactor, a flocculation unit, a sedimentation tank, and a filter. Parameters evaluated included suspended solids, orthophosphate, ammonia, BOD₅, total bacteria, and coliform reduction. In the study, iron (VI) ferrate was found to be effective in reducing the above mentioned wastewater parameters in the system. With a ferrate concentration of 10mg/L as FeO₄²^-, from typical secondary effluent values, reductions of the following order were observed: the suspended solids in the effluent of the sedimentations unit were reduced by 85%, ortho-phosphate by 53%, ammonia by 60%, BOD₅ by 86%, total bacteria by 91%, fecal coliform by 99.99%, and total coliform by 99.98%.