Innovative Metals Recovery

High performance adsorption & ion exchange solutions that recover metals and catalysts for reuse in a broad range of process environments.

Selenium, Chromium and Arsenic Removal Using Iron-based Sorbent Media

Envirogen’s Advanced Metals Removal System (AMRS) can be employed for applications with very low effluent limits for difficult to remove metals such as selenium, chromium and arsenic. The AMRS relies on Höganäs’ Cleanit® technology, a unique, engineered zero valent iron media that has extremely high porosity, surface area and reactivity and therefore provides exceptional adsorptive capacity. Together the solution delivers extremely high removal efficiencies allowing customers to comply with stringent wastewater discharge permit limits. Several pilot studies have demonstrated the effectiveness of the Envirogen Advanced Metals Removal System (AMRS) featuring Cleanit® to reduce selenium levels to single digit parts per billion, even when faced with the more difficult-to-treat species such as selenate. Cleanit® has also been proven to be effective in removing arsenic, chromium and other heavy metals, with full-scale applications in Brazil and additional successful pilot studies in California and Brazil.

A visual comparison of the Envirogen AMRS media to competing Zero Valent Iron (ZVI) media can be seen below:

comparison of the Envirogen AMRS media to competing Zero Valent Iron (ZVI) media

Advanced Metal Removal System Advantages

  • High porosity and large surface area (>100x surface area compared to normal ZVI)
  • High Reactivity (>10x compared to normal ZVI)
  • Higher contaminant adsorption capacity

In many applications, the Cleanit® media can be recycled for reuse, thus avoiding a disposal issue for the user site. Envirogen offers this advanced treatment on a warranted basis in terms of performance, operating requirements and asset life.

Depending on the nature of the application, wastewater composition, and discharge limits, Envirogen may employ their proprietary Fluidized Bed Reactor (FBR) System upstream of the final polishing AMRS step. The FBR relies on bacteria to reduce soluble selenium to insoluble elemental selenium, which is readily removed via filtration. Residual selenium species can effectively be adsorbed using the AMRS with Cleanit® to reach effluent levels that have previously been extremely difficult to achieve.

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