Effects of Ferrate (VI) Pre-oxidation in the Coagulation Treatment of Drinking Water

Abstract

Although ferrate (Fe(VI)) is introduced as a feasible replacement for pre-oxidation in the treatment of drinking water, limited research is available on effects of utilizing ferrate for the treatment of drinking water sources to produce potable water. In the present study, an experimental program was conducted on the employment of ferrate in drinking water treatment; this program included batch and continuous flow tests on multiple samples of natural water from different sources. According to the batch test results, the ferrate pre-oxidation led to improved ultraviolet light-absorbing compounds (UV254) removal by subsequent coagulation in a small portion of the samples but showed no enhancement in the majority of samples. In continuous flow tests, ferrate was added to small-scale models of existing treatment plants. Compared to the case with no pre-oxidation, ferrate pre-oxidation generally enhanced UV254 absorption, finished water turbidity, and disinfection by-product formation. Therefore, ferrate can be viably used in the treatment systems of drinking water and provide a superior replacement to available oxidants by allowing for the oxidation and disinfection of inorganic materials without negative effects on downstream processes. More researches are needed to examine a more viable combination of ferrate with other methods and obtain more knowledge about the mechanisms of the known synergistic applications of ferrate.