TECHNICAL PAPERS
Commissioning and Long-Term Operation of Non-Biological Selenate Removal Systems
This paper presents commissioning data and multi-year operating results from four full-scale, non-biological selenate removal plants across Canada and the US. It covers startup lessons, electro-reduction anode maintenance, and resin conditioning, building the operating track record that supports non-biological treatment as a proven, field-tested option.
TECHNOLOGY
Selen-IX™ (Ion Exchange + Electro-reduction); Nanofiltration combined with Electro-reduction for simultaneous sulphate and selenium removal
APPLICATION
Commissioning, startup and long-term operation of full-scale selenate removal plants
LOCATION
Northern British Columbia, Canada; multiple sites, USA
PUBLISHED
Mine Water Solutions 2025, Vancouver, Canada
AUTHORS
H.C. Liang, Brent Baker, Andrew Deheer, Veneil Sundar, David Kratochvil
SCOPE
Commissioning results, operational lessons learned and multi-year performance data across four industrial-scale plants (2020–2023)
KEY TOPICS COVERED
- Commissioning and startup of full-scale Selen-IX™ plants
- Long-term operating data across four industrial sites in Canada and the US
- Electro-reduction anode changeout and maintenance planning
- Ion exchange resin conditioning for reliable Selen-IX™ startup
- Non-biological treatment performance against design expectations
TECHNICAL SUMMARY
Selenium management is one of the fastest-evolving areas of mine water treatment, driven by its persistence in the environment and increasingly stringent regulations covering both water quality and fish tissue. Where biological selenate removal has struggled with dilution dependency, organo-selenium formation and poor adaptability to variable flow, non-biological treatment using ion exchange and electro-reduction has now moved from pilot to full industrial scale.
This paper documents the commissioning and ongoing operation of four full-scale plants built between 2020 and 2023, including the original Kemess Selen-IX™ plant in northern BC and three further installations in the US treating coal ash pond water and combined sulphate/selenium loads. At Kemess, commissioning ran through the 2020 COVID-19 disruption, with dry commissioning in late 2019 followed by wet commissioning and a 14-day performance test completed in September 2020. The plant met its 2 ppb selenium target consistently, with results below the 0.5 ppb ICP-MS detection limit.
Operational experience across the four sites produced practical lessons that hadn’t previously been in the public domain. At the coal ash pond facility, anode wear in the electro-reduction circuit proved highly predictable using voltage monitoring and Coulombs per litre, within 10% of theoretical values, allowing anode changeouts to be scheduled around a reliable ~20-hour downtime window. A separate lesson concerned strong base anion resin: it must be properly converted to sulphate form and rinsed before use in the Selen-IX™ ion exchange circuit, a step that is easy to underestimate during commissioning.
Across all four plants, non-biological treatment demonstrated the intermittent and seasonal operating flexibility that biological systems typically can’t match, alongside consistent, low-volume, stable residue suitable for co-disposal with tailings.
KEY FINDINGS
- Four full-scale non-biological selenate removal plants commissioned and operating between 2020 and 2023, meeting end-of-pipe selenium limits ranging from 1.5 to 10 ppb
- Kemess plant achieved selenium below 2 ppb, with results below the 0.5 ppb detection limit
- Electro-reduction anode consumption was predictable to within 10% of theoretical values using voltage and Coulomb/L monitoring
- Correct SBA resin conditioning (conversion to sulphate form) proved essential to reliable Selen-IX™ startup
- Non-biological systems handled intermittent and seasonal operation reliably, addressing a known weakness of biological treatment