Abstract
We have studied and determined the most suitable electrolytic conditions and applied them to the biological filtration process by the electrochemical elution of iron, but have not made it clear whether to apply them to the activated sludge process.
In this study, we examined phosphorus removal, dehydrogenase activity and oxygen uptake rate using an experimental activated sludge system for the electrochemical elution of iron in the laboratory. This method was successful in more than 70% phosphorus removal while maintaining an Fe:P ratio of more than 0.75, a current density 0.25mA·cm-2 and an intermittent operation of electrolysis. Phosphorus removal technologies based on the electrochemical elution of iron usually require an Fe:P ratio of 1.5. Our results were achieved by combining our system with a biological process that maintains phosphorus. This combined method offers high stability and provides more than two months of phosphorus removal. The electrochemical elution of iron does not negatively affect the performance of the biological treatment. The effluent BOD and nitrogen concentrations were not increased by introducing this method.
Moreover, the unit features a compact design and a low operating cost. In view of this, we consider that phosphorus removal technologies that incorporate electrochemical elution of iron can be provided for any wastewater treatment systems.
