Selenium, Chromium and Arsenic Removal Using FerroLock™ Zero Valent Iron Media
Zero Valent Iron (ZVI) media effectively neutralize or eliminate specific pollutants, without generating toxic byproducts. The ZVI media reacts with the contaminants and removes them from the contaminated water.
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 ZVI in an active water treatment system.
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.
The Advanced Metals Removal System (AMRS) is an active water treatment system that allows use of multiple ZVI formulations to accomplish metals removal. Compared to conventional ZVI system designs, the AMRS design is up to 50% lower in capital cost and provides the fluidization flow flexibility needed to utilize multiple types and grades of ZVI formulations. It is also unlike the in-situ approach more commonly employed with ZVI for metals removal from water, and offers a number of advantages including:
- Reduced physical footprint
- Ability to effectively operate over a range of conditions and contaminant concentrations
- Automatic pH adjustment to optimize removal efficiency
- Pilot validation available and recommended
- Achieve permit compliance consistently
- Treated water can be safely discharged with no toxicity impact
Our proprietary Advanced Metals Removal System (AMRS) can be engineered to address specific contaminants, influent concentrations, and effluent limits for your application.
The Envirogen AMRS utilizes our FerroLock™ Zero Valent Iron technology to deliver high removal efficiencies of selenium, chromium and arsenic from water allowing customers to comply with stringent wastewater discharge permit limits. FerroLock™ ZVI media reacts with the contaminants, effectively neutralizing and adsorbing them, without generating toxic byproducts.
FerroLock™ Media Characteristics:
- High surface area
- Mechanisms employed are adsorption and chemical reduction
- Insoluble metals and iron-metal complexes remain on the media
- Insoluble metals are not released
- More effective on some metals than other chemical reduction processes, with no chemicals to handle
Envirogen’s Advanced Metals Removal System (AMRS) equipped with FerroLock™ Zero Valent Iron media can be employed for applications with very low effluent limits for difficult to remove metals such as selenium, chromium and arsenic. It is employed primarily for groundwater and wastewater remediation.
Envirogen’s approach is to examine the characteristics of your wastewater and select the best FerroLock™ ZVI to use from an overall performance, longevity, and life cycle cost standpoint. We will consider concentrations of certain salts that can quickly dissolve the iron from some ZVIs. In addition, sulfate affects some ZVI formulations more than others.
The ability of Envirogen’s AMRS to utilize different ZVIs that range in size, reactivity and cost is a unique benefit for you to consider.
Pilot and/or lab scale testing is available and recommended.
Pilot and/or lab scale testing will be employed to determine:
• Performance vs. contact time (full-scale system size)
• Media regeneration frequency
• Iron solubilization rate and post-treatment requirements
A recent pilot study for treatment of coal ash pond water has demonstrated the effectiveness of the AMRS with Zero Valent Iron to reduce selenium levels to single digit parts per billion, even when faced with the more difficult-to-treat species such as selenate.
To learn more about Envirogen’s pilot success in CCR Ash Pond Water, download our Case Study here.
Further Reading on Advanced Metals Removal Systems