bnr-Selenium Treatment
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Selenium Treatment – Saturated Rock Fill Process

Selenium is one of the chemical elements found in mineral deposits of economic value; however, its presence poses a challenge in contact water treatment. Globally, WSP has experience in the design, implementation, and operation of this type of treatment plant.

Although it is a regulated element in most countries in South America, no selenium treatment plants have been built in our region. As part of our commitment to providing our clients innovative services that meet technical quality requirements and international standards, WSP in Peru conducted laboratory-scale tests using the Saturated Rock Fill (SRF) passive process for selenium treatment at its lab in Lima, gathering input data for designing treatment plants using this process.

The SRF process functions as a bioreactor with a long retention time, as mine water is injected along with a carbon source and nutrients, which help enhance microbial growth. Additionally, anaerobic-anoxic conditions are created, which are optimal for the microbial treatment of selenium and nitrate. One of the advantages of this process is that it uses materials from the mine’s surroundings, such as substrates (waste rock and sediments), and can use mine closure components (open pits) as bioreactors.

Location

  • Lima, Peru

Project Status

  • Completed

Scope of the Project and Phases

Our client identified sources of contact water with dissolved selenium in their mining operations and requested WSP to present treatment options for the removal of this parameter. WSP conducted a trade-off analysis, conceptual engineering, and prefeasibility engineering for selenium treatment. As part of the treatment options, WSP proposed the passive SRF treatment process and conducted laboratory-scale tests over 24 weeks to determine the efficiency of selenium removal with this process.

  • The SRF process proved to be highly efficient for nitrate and selenium removal, with average removal rates exceeding 97%.

  • It was proven that the use of waste rock and mine sediments as substrates for the SRF process reaction worked efficiently.

Other challenges that we have overcome