Bioreactor Configurations for Ex‐Situ Treatment of Perchlorate: A Review

Abstract

The perchlorate anion has been detected in the drinking water of millions of people living in the United States. At perchlorate levels equal to or greater than 1 mg/L and where the water is not immediately used for household purposes, ex‐situ biotreatment has been widely applied. The principal objective of this paper was to compare the technical and economic advantages and disadvantages of various bioreactor configurations in the treatment of low‐ and medium‐strength perchlorate‐contaminated aqueous streams. The ideal bioreactor configuration for this application should be able to operate efficiently while achieving a long solids retention time, be designed to promote physical–chemical adsorption in addition to biodegradation, and operate under plug‐flow hydraulic conditions. To date, the granular activated carbon (GAC) or sand‐media‐based fluidized bed reactors (FBRs) and GAC, sand‐, or plastic‐media‐based packed bed reactors (PBRs) have been the reactor configurations most widely applied for perchlorate treatment. Only the FBR configuration has been applied commercially. Commercial‐scale cost information presented implies no economic advantage for the PBR relative to the FBR configuration. Full‐scale application information provides evidence that the FBR is a good choice for treating perchlorate‐contaminated aqueous streams.