Fluidized bed bioreactor treatment of perchlorate–laden groundwater to potable standards

Abstract

During the past decade, perchlorate at levels above regulatory standards has become increasingly prevalent in drinking water aquifers. A large pilot‐scale biological fluidized bed reactor (FBR) followed by a surface water treatment plant was tested to demonstrate effective treatment of perchlorate‐laden groundwater to potable water. At perchlorate concentrations up to 1,000 μg/L, nitrate‐nitrogen concentrations of 6.1 mg/L, and flow rates of 95‐189 L/min (25‐50 gpm), the FBR treatment plant was effective in removing perchlorate and producing potable water that met all drinking water regulations before disinfection. The use of on‐line perchlorate and nitrate analyzers allowed for rapid analysis of plant performance and provided continuous electron donor feed control to maintain optimal contaminant treatment rates. Recovery from feed and plant electrical interruptions was rapid in achieving acceptable treatment performance. Study results provided essential design data for a potential full‐scale treatment plant.