ENV-09-38 Selenium Removal from Refinery Wastewater

Description:

The current selenium removal technologies include iron co-precipitation, constructed wetlands, and copper precipitation. The new selenium removal technologies focus on reduction of selenite and selenate species to elemental selenium to avoid generating large quantities of hazardous waste sludge. The selenium reduction can be accomplished by anoxic biological treatment using selenium reducing organisms (e.g., ABMet®, BioSove®, MBfR® processes) or by chemical methods (e.g., SMI®, ZVI, and ferrous-based reduction processes). This paper provides the potential selenium removal technologies and discusses their mechanisms, features, and benefits. The selenium removal methods are compared for their effectiveness in treating various selenium species: selenite, selenate, and selenocyanate. The technologies choices pioneered in the Bay Area will affect all U.S. refineries.