Ferrate is a type of supercharged iron particle, in which iron is in the plus 6 oxidation state – it’s also known as Iron (VI). That might not interest you, but perhaps this will: it can be used as an environmentally-friendly disinfectant in water treatment applications, reportedly outperforming stand-bys such as ultraviolet light, hydrogen peroxide, and chlorine. So, why isn’t it in common use? Unfortunately, it’s proven too expensive to produce, package and transport. Ferrate Treatment Technologies (FTT), however, claims to have addressed that limitation with its product, the Ferrator.
Using the Ferrator, liquid ferrate can be synthesized on-site using common bleach, caustic soda and ferric chloride. Traditionally, ferrate has cost over US$20 a pound, and has had to be shipped from off-site locations. Using its process, however, FTT claims that ferrate can be manufactured for over 90 percent less than conventional methods. It also doesn’t have to be shipped, which further saves money and allows it to be used when it’s at its freshest, most potent state.
When the Ferrator is in use, the liquid ferrate is pumped directly into water treatment process streams in municipal or industrial settings, and can be used both to pretreat drinking water and to clean up post-consumer wastewater and sludge. Because the unit is self-contained, the company states that it can easily be incorporated into the infrastructure of existing plants.
When added to water, ferrate gradually works its way down to a plus 3 oxidation state, thus becoming non-toxic Iron (III). As it reduces, it acts first as an oxidant, then as a coagulant, and finally as a flocculent (meaning it causes contaminants to clump together for removal) – all in a single dose.
In FTT’s lab tests, effluent containing the residual Iron(III) – also known as ferric hydroxide – was shown to have no observable effect on three reproductive lifecycles-worth of Daphnia freshwater microcrustaceans. The company claims that the disinfection process itself also creates no harmful byproducts, which is not the case with chlorine and ozone.
Ferrators are currently being tested at two water treatment plants in FTT’s home state of Florida.
Via The Economist