We Do Selenium Better

Selenium’s Unique Challenge

More than any other contaminant, selenium can be tricky to remove from your wastewater.

• Selenate's High Solubility: Most selenium in wastewater exists as selenate, a soluble form that doesn't easily bind to common treatment materials like flocculants or ion-exchange resins.

• Slow Reduction Kinetics: To make selenium insoluble, it needs to be reduced to elemental selenium. However, this reduction process is slow, especially for selenate.

• Interference from Competing Ions: The wastewater contains high levels of sulfate, which is chemically similar to selenate, and nitrates. Microbes preferentially reduce nitrates over selenates, meaning nitrates must be dealt with first, slowing down selenium removal.

• Variable Wastewater Composition: The wastewater source and process creates significant variability in the wastewater's composition and selenium speciation (the relative amounts of selenate and selenite).

• Limited Treatment Effectiveness: Standard precipitation and adsorption technologies are less effective for soluble selenate. Specialized biological processes are often required but can be slow, complex, and require large reactor volumes.