A method for determining VOC biotransformation rates

A method was developed for determining biotransformation rate coefficients for volatile organic compounds in activated sludge systems. It consisted of a sealed batch reactor containing primary substrate, VOCs and biomass. A b ubbleless oxygenation system was used to supply oxygen. Two types of substr ate were studied to determine method reliability; domestic wastewater and s ynthetic wastewater, as were various conditions; abiotic, biotic, anaerobic , anoxic denitrifying and aerobic. The anaerobic and anoxic denitrifying co nditions revealed minimal VOC biotransformation, while under aerobic condit ions, the method successfully measured mixed second-order biotransformation rate coefficients for the ten VOCs studied. The proposed method will be us eful to designers and operators of wastewater treatment plants, who need re liable kinetic parameters to predict the fate of contaminants in wastewater treatment plants. (C) 2000 Elsevier Science Ltd. All rights reserved.