Ferrate(VI) is an oxidant; under acidic conditions, the redox potential of ferrate(VI) salt is the strongest among all oxidants used for water and wastewater treatment. Ferrate(VI) is also a coagulant; during the oxidation process, ferrate(VI) ions are reduced to Fe(III) ions or ferric hydroxide, which simultaneously generates a coagulant in a single dosing and mixing unit process. The superior performance of ferrate(VI) as an oxidant/disinfectant and coagulant in water and wastewater treatment has been extensively studied. However, challenges have existed to the implementation of ferrate(VI) technology in water and wastewater treatment practice due to the instability of the ferrate(VI) solutions and a high preparation cost of a solid ferrate(VI). It would be an ideal approach to generate ferrate(VI) in situ and apply the generated ferrate(VI) directly for wastewater treatment. This paper reports the online preparation and use of ferrate(VI) for sewage treatment at a pilot scale applied in a wastewater treatment plant in the UK.
- wastewater treatment
- phosphate removal