Removal of Heavy Metals from Wastewater – Zero Valent Iron Technology

How does zero valent iron in water treatment work?

ZVI media is a granular product used for remediation to remove chemical constituents either via sequestration or reduction reactions. While ZVI has been used for in-situ applications in the form of a permeable reactive barrier (PRB), Envirogen has developed an alternative use of zero valent iron in an active water treatment system for the removal of heavy metals from wastewater including selenium, chromium, arsenic, and other oxyanion contaminants.

How does Envirogen differentiate themselves in the ZVI market?

Envirogen has completed extensive research and testing of various iron-based media available in the market to understand the performance differences and to allow selection of the optimum zero valent iron media for each application. Results of that study can be found in our ZVI Media Evaluation Whitepaper. As a result, Envirogen has developed the proprietary FerroLock™ ZVI media.

Advanced Metals Removal System (AMRS) with FerroLock™ zero valent iron (ZVI) media

Envirogen has developed a proprietary active water treatment system, AMRS, that utilizes our FerroLock™ ZVI media to remove selenate, arsenate, chromate and other oxyanion contaminants.

This unique AMRS system is engineered to operate optimally regardless of media size and density. You are never locked into a single media. The AMRS can utilize Envirogen’s specially formulated FerroLock™ ZVI or other iron-based media to deliver high removal efficiencies allowing customers to comply with stringent wastewater discharge permit limits.

Removal of heavy metals from wastewater: Envirogen’s AMRS technology
for the treatment of selenium, chromium, arsenic, and other oxyanion contaminants.

Envirogen advanced metal removals and media products

Whitepaper – Evaluation of zero valent iron and other iron-based media for selenium reduction in water

Iron-based media, including zero valent iron (ZVI) and chemically modified iron, have found use for removal of selenium from contaminated aqueous streams such as found in coal ash ponds, flue gas desulfurization wastewater, mining, and refining applications. The iron-based media available in the market comes in a wide range of specifications that affect performance and cost, both capital and operating, for the end user. Envirogen has developed a versatile and flexible, upflow, fluidized, active water treatment system, the advanced metals removal system (AMRS), that utilizes multiple iron-based media.

The purpose of this study was to understand and compare the performance of several iron-based media, including their ability to remove selenium, fluidization characteristics that impact treatment vessel size, iron attrition rates, and the impact of high chloride and sulfate. The extensive data gathered in our pilot facility will benefit clients in the proper selection of media, that will ultimately make a critical difference in compliance and system lifecycle costs for each specific customer’s application.

Case study – removal of heavy metals from wastewater

Discover how a pilot study for treatment of coal combustion residuals (CCR) ash-pond water demonstrates the effectiveness of the AMRS with zero valent iron, on the East Coast USA, to reduce selenium levels to single digit parts per billion, even when faced with the more difficult-to-treat species such as selenate.