Final Report: Use of Ferrate in Small Drinking Water Treatment Systems

EPA Grant Number: R835172
Title: Use of Ferrate in Small Drinking Water Treatment Systems
Investigators: Reckhow, David A. , Rees, Paula , Tobiason, John
Institution: University of Massachusetts - Amherst
EPA Project Officer: Page, Angela
Project Period: December 1, 2011 through November 30, 2014 (Extended to November 30, 2015)
Project Amount: $497,078
RFA: Research and Demonstration of Innovative Drinking Water Treatment Technologies in Small Systems (2011) RFA Text |  Recipients Lists
Research Category: Drinking Water , Water

Objective:

The objective was to test the ability of ferrate oxidation to solve a wide range of water quality and treatment problems faced by small systems. The general working hypothesis is that ferrate is: (1) more effective and less detrimental than existing conventional oxidative technologies, such as chlorination, chloramination and permanganate oxidation; and (2) comparable in performance to advanced technologies, such as ozonation or chlorine dioxide oxidation, that are more costly, are more hazardous or require specialized expertise to operate.

Summary/Accomplishments (Outputs/Outcomes):

The project has focused on bench-scale and continuous-flow testing of ferrate oxidation for small drinking-water treatment systems. Lab-scale studies have examined the impacts of ferrate in raw waters that include natural organic matter (NOM) and bromide, and that are also treated with coagulants and chlorine. The future of ferrate as a potable water treatment chemical depends on its ability to achieve adequate disinfection while minimizing the formation of disinfection byproducts (DBPs) under these realistic scenarios.

In this project, laboratory-scale treatment studies were conducted to (1) clarify the stability of ferrate in natural waters under various conditions, (2) re-examine the ability of ferrate to oxidize bromine species, (3) explore the interactions of ferrate and coagulants in controlling DBP precursors, and (4) document the impacts of pre- and intermediate ferrate on conventional treatment. As of the end of this project period, we have conducted abbreviated assessments with two raw waters and full assessments with 13 additional waters. The DBP compounds (and their precursors) being studied include the trihalomethanes (THMs), all nine haloacetic acids (HAAs), the haloacetonitriles (HANs), the haloacetamides (HAMs), the halonitromethanes (HNMs) and the haloketones (HKs).

Results showed that ferrate decay is catalyzed by ferrate decomposition products. Solutes capable of forming complexes with iron hydroxides retard ferrate decay. In natural waters, NOM and bicarbonate inhibit the catalytic effects of ferrate decomposition products and stabilize ferrate.

Ferrate oxidizes bromide, forming bromine and bromate, and in natural waters total organic bromine (TOBr) also is detected. The highest levels of bromine and bromate are formed at lower pH and in the absence of phosphate. Nevertheless, under environmentally relevant conditions, the formation of bromate and TOBr would not be a problem for ferrate application, as their concentration levels are quite low.

The effectiveness of ferrate oxidation in combination with conventional treatment on DBP precursor removal was investigated. Results showed that intermediate-ferrate treatment (i.e., conventional treatment followed by ferrate oxidation) is most effective followed by pre-ferrate treatment (i.e., ferrate oxidation followed by conventional treatment) or conventional treatment alone, and the least effective is ferrate oxidation alone.

Conclusions:

In general, ferrate shows great potential for drinking water treatment because: (1) at moderate doses, ferrate is sufficiently stable to result in CT values that are effective to inactivate pathogens in natural waters; (2) the TOBr and bromate yields from ferrate oxidation were quite low; (3) ferrate oxidation following coagulation (i.e., intermediate-ferrate treatment) showed substantially higher effectiveness for NOM and DBP precursor removal than conventional treatment; (4) ferrate resultant particles can be effectively destabilized and may provide additional downstream benefits through contaminant adsorption; (5) the addition of ferrate to a continuous flow treatment system does not have significant negative impacts on media filtration operation; and (6) ferrate rapidly oxidizes manganese without significant competition from NOM. 

Our broad perspective on ferrate for use in small utilities is quite positive. It offers a very attractive alternative to ozonation, providing oxidation and disinfection without producing chlorinated DBPs. Furthermore, it is simpler to apply than ozone, and we expect it will prove to be less expensive and less energy intensive.

References:

Carr JD. Kinetics and product identification of oxidation by ferrate(VI) of water and aqueous nitrogen containing solutes. Abstracts of Papers of the American Chemical Society. 2006;232:495.

Lee Y, Kissner R, von Gunten U. Reaction of ferrate(VI) with ABTS and self-decay of ferrate(VI): Kinetics and mechanisms. Environmental Science & Technology 2014;48:5154-5162. doi:10.1021/es500804g

Sharma VK. Oxidation of inorganic compounds by ferrate(VI) and ferrate(V): One-electron and two-electron transfer steps. Environmental Science & Technology 2010;44:5148-5152. doi:10.1021/es1005187


Journal Articles on this Report : 6 Displayed | Download in RIS Format

Other project views: All 12 publications 7 publications in selected types All 6 journal articles
Type Citation Project Document Sources
Journal Article Goodwill JE, Jiang Y, Reckhow DA, Tobiason JE. Laboratory assessment of ferrate for drinking water treatment. Journal: American Water Works Association 2016;108(3):E164-E174. R835172 (Final)
R835602 (2015)
R835602 (2016)
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  • Journal Article Goodwill JE, Mai X, Jiang Y, Reckhow DA, Tobiason JE. Oxidation of manganese(II) with ferrate: stoichiometry, kinetics, products and impact of organic carbon. Chemosphere 2016;159:457-464. R835172 (Final)
    R835602 (2015)
    R835602 (2016)
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  • Journal Article Jiang Y, Goodwill JE, Tobiason JE, Reckhow DA. Effect of different solutes, natural organic matter, and particulate Fe(III) on ferrate(VI) decomposition in aqueous solutions. Environmental Science & Technology 2015;49(5):2841-2848. R835172 (Final)
    R835602 (2016)
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  • Journal Article Jiang Y, Goodwill JE, Tobiason JE, Reckhow DA. Bromide oxidation by ferrate(VI): the formation of active bromine and bromate. Water Research 2016;96:188-197. R835172 (Final)
    R835602 (2016)
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  • Journal Article Jiang Y, Goodwill JE, Tobiason JE, Reckhow DA. Impacts of ferrate oxidation on natural organic matter and disinfection byproduct precursors. Water Research 2016;96:114-125. R835172 (Final)
    R835602 (2016)
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  • Journal Article Pakbin P, Ning Z, Schauer JJ, Sioutas C. Characterization of particle bound organic carbon from diesel vehicles equipped with advanced emission control technologies. Environmental Science & Technology 2009;43(13):4679-4686. R835172 (Final)
    R832413 (Final)
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  • Supplemental Keywords:

    Oxidation, NOM, DBPs, PPCPs, drinking water systems, ferrate, water treatment

    Progress and Final Reports:

    Original Abstract
  • 2012 Progress Report
  • 2013 Progress Report
  • 2014 Progress Report