Biooxidation of coal gasification wastewaters using fluidized‐bed bioreactors

Abstract

Abstract Process condensate wastewaters from two fixed‐bed gasifiers have been treated successfully using a laboratory‐scale, fixed‐film, fluidized‐bed bioreactor. Both dilute (1 to 2% raw wastewater) and more concentrated (50% stripped wastewater) were treated continuously for periods of one to three months. Biological activity was stable, recovery from upsets was rapid, and reaction rates were high due to the high concentration of microorganisms retained on the support particles. Removal of phenolics exceeded 99%, and removal of chemical oxygen demand was typically 75 to 85% for the 50% stripped wastewater with a hydraulic residence time in the bed of ˜5 to 7 h. Sludge production rates were comparable to rates in suspended growth systems.