Respirometric study of the biooxidation of phenolic compounds by activated sludge

C.C. LOBO; N. BERTOLA; E.M. CONTRERAS

Santiago

Congreso; XXV Interamerican Congress of Chemical Engineering & XVIII Chilean Congress of Chemical Engineering; 2011

In the present work, a respirometric technique was used to study the toxic effect of intermediates generated during the partial oxidation of phenol by physicochemical treatments (resorcinol, pyrogallol, p-hydroquinone) or during its biodegradation (phenol, catechol) on the respiration rate of activated sludge. Activated sludges were cultured in a laboratory scale (2.5L) cylindrical semi continuous reactor. Hydraulic retention time was 3.3 days and cellular retention time was 45 days. Activated sludges were acclimated to phenol using a culture medium with 300 mg L-1 of phenol as the sole source of carbon and energy Activated sludges acclimated to 300 mg L-1 of phenol were able to biooxidate not only phenol and catechol, but also some compounds are commonly found in the oxidation of phenol using physicochemical methods, such as resorcinol, pyrogallol, and p-hydroquinone. In most cases, a decrease of the respiration activity was obtained as a function of the number of pulse, indicating a certain degree of toxicity towards its own biooxidation. On the contrary, the stoichiometric parameter YO/S remained almost constant. These results may help in developing a mathematical model to describe the biooxidation by activated sludge of the compounds tested in the present work.