Determination of biodegradation kinetics of volatile organic compounds through the use of respirometry

Electrolytic respirometry was used to determine the biodegradation kinetic parameters of five volatile aromatic organic compounds: benzene, 1,2‐dichlorobenzene, 1,3‐dichlorobenzene, 1,4‐dichlorobenzene, and 1,2,3‐trichlorobenzene. A protocol developed earlier was modified to accommodate the volatile characteristic of the test compounds. Specifically, the model used in data analysis was modified using Henry's law constant to incorporate the effect of partitioning of a volatile substrate between the gas and liquid phases in a batch reactor. Similar kinetic parameters were obtained for benzene and its four chlorinated analogs. Substrate inhibition was observed in the case of 1,3‐ and 1,4‐dichlorobenzene, and intermediate product inhibition was observed in the case of 1,2‐dichlorobenzene. In addition, all chlorinated benzenes exhibited complete inhibition above certain threshold concentrations.