| Abstract: | The feasibility of automating biodegradation tests was evaluated by comparing the results obtained using an Anachem SK233 automation system linked to an HPLC, and the traditional shake flask method using a shaker incubator and manual sampling. For the purpose of this study, several series of biodegradation kinetics were performed using a range of halogenated compounds which are common starting materials in organic synthesis. The first experiment involved two series of Fluorocinnamic Acid biodegradation kinetic tests performed over a period of 5 days. Several initial concentrations were used. Results obtained using the automated and manual methods were in very good agreement, with variations in absolute concentrations and kinetic constants ranging, between 10 % and 27 %. Half‐life values calculated from kinetic data ranged between 3.6 and 25.6 hours, depending on the initial organic compound concentrations (range 5 to 100 mg L–1) and the activity of the activated sludge employed. In the second part of this study, the degradation of Bromobenzoic Acid, Chlorobenzoic Acid and Iodobenzoic Acid by activated sludge were investigated. Significant differences in the lag periods were observed. Differences in the hydrodynamics and the configuration of the vessels may contribute to the variations observed. However, it was found that for 4‐Iodobenzoic Acid, manual and automated methods yielded comparable first order kinetic values for the exponential growth bacterial cycle. 4‐Bromobenzoic Acid, 4‐Chlorobenzoic Acid and 4‐Iodobenzoic Acid rates of disappearance were estimated and complete removal on the shake flasks was observed after 72, 66 and 96 hours respectively. The results are very promising and open a lot of possibilities for future automation of a range of biodegradation and inhibition tests. |
