TECHNICAL PAPERS
Selenium Removal from Mining Affected Runoff
This paper explores selenium removal from mining affected runoff using Selen-IX™ ion exchange technology. It demonstrates how selenium oxyanions can be selectively removed to very low levels, even in challenging conditions such as cold temperatures, high flow rates and complex water chemistry.
TECHNOLOGY
Selen-IX™ (Ion Exchange with regenerant treatment)
APPLICATION
Selenium removal from mining affected runoff and mine water
LOCATION
Canada (pilot plant operation on mine impacted water)
PUBLISHED
Hydrometallurgy 2014
AUTHORS
F. Mohammadi, P. Littlejohn, A. West, A. Hall
SCOPE
Laboratory testing and pilot-scale validation of ion exchange selenium removal technology
KEY TOPICS COVERED
- Selenium removal from mining affected runoff using ion exchange technology
- Challenges of treating selenate and selenite in mine water
- Selen-IX™ process design including ion exchange and regenerant treatment
- Pilot plant validation under real mine water conditions
- Cost comparison with biological and conventional selenium treatment technologies
TECHNICAL SUMMARY
Selenium removal from mining affected runoff has become increasingly important due to stricter environmental regulations and the risk of bioaccumulation in aquatic ecosystems. Selenium in mine water is typically present as selenate and selenite, with selenate being more difficult to remove due to its chemical stability and similarity to sulphate. :contentReference[oaicite:0]{index=0}
This paper presents Selen-IX™, an ion exchange-based process designed to selectively remove selenium oxyanions from mine impacted water. The system uses a strong base anion exchange resin to capture selenium, achieving effluent concentrations below 5 µg/L even in complex water chemistries and low temperature environments.
Following ion exchange, the process includes a regenerant treatment stage where selenium is removed from the concentrated brine and converted into a stable solid product. This allows the regenerant solution to be recycled, eliminating liquid waste streams and reducing reagent consumption.
Laboratory testing demonstrated strong ion exchange performance, with selenium breakthrough occurring only after significant loading volumes and consistent regeneration efficiency. Pilot plant operation confirmed the system’s ability to treat real mine water, maintaining low effluent selenium concentrations under varying operating conditions.
The Selen-IX™ process is particularly suited for large flow, low concentration applications such as mining affected runoff. Its modular design, low footprint and ability to operate at ambient temperatures make it a practical alternative to biological treatment systems, especially in remote or cold environments.
KEY FINDINGS
- Achieved selenium concentrations below 5 µg/L in treated water
- Effective removal of both selenate and selenite from mine impacted runoff
- Successful pilot operation under real site conditions with cold water temperatures
- Regenerant recycling eliminates liquid waste and reduces operating costs
- Lower capital and operating costs compared to biological and conventional treatment systems