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Apex Engineering, PLLC

Sulfate Removal from Kinross Tailings Underdrain
Apex Engineering designed and helped to install and optimize a biological sulfate and nitrate removal system for Kinross Gold Corporation for groundwater seeping from its tailings impoundment.  The system, comprising three tanks in series filled with plastic media and an inoculum from the Stillwater Mining Company, reduces nitrate-N concentrations from 6 mg/L to less than 1 mg/L, and reduces sulfate concentrations from 120 mg/L to about 20 mg/L.  Groundwater concentrations at downgradient monitoring wells are now in compliance with State of Washington standards.
Sulfate removal bioreactor designed by Apex Engineering
Bioreactors for sulfate removal and nitrate removal
The sulfate removal system shortly after start-up.
Papers and presentations on this project: