An experimental study on iron removal with ferric sludge recycling

Abstract

An iron removal process, which makes use of the catalytic effect of ferric iron, is proposed. For this purpose, the reaction kinetics derived from the data of the batch experiments was applied to the continuous flow system. Based upon this reaction kinetics, it has been theoretically demonstrated that the Volumes of aeration tanks can be significantly reduced by keeping a high concentration of ferric iron in the reactor. However, in natural waters, Fe(ll) is found commonly to be in the range of 0.01-10 mg/l. These ferrous iron concentrations are not high enough to maintain the high concentrations of ferric iron in the aeration tank. Therefore, similar to the activated sludge processes used in wastewater treatment, it is suggested that the required Fe(lll) concentrations can be maintained by recycling Fe(OH)(3) sludge back to the aeration tank.