BIODEGRADATION OF P-TOLUENESULPHONIC ACID BY COMAMONAS-TESTOSTERONI IN AN AEROBIC COUNTERCURRENT STRUCTURED PACKING BIOFILM REACTOR

p-Toluenesulphonic acid degradation by Comamonas testosteroni was stud ied in a continuously operated fixed-bed biofilm reactor. Static mixer elements (Sulzer Chemtech, Switzerland) were used as a support matrix for biofilm formation. Degradation of p-toluenesulfonate was investig ated at several aeration (0.5-4 L min(-1)) and dilution (0.15-0.4 h(-1 )) rates under septic conditions. The maximum observed pollutant degra dation rate was 198 mg of C L(-1) h(-1). In spite of nonsterile condit ions, a very limited range of microbial species was present in the rea ctor. The system was operated for over 3 months and Comamonas testoste roni used as inoculum was largely present in the biofilm (about 60% of the total microbial population) during the whole cultivation period. Two other aerobic bacterial strains detected in the biofilm were not a ble to degrade p-toluenesulphonic acid. High biomass attachment was ob served on polypropylene static mixers. Immobilised biomass reached the level of 10.4 g of dry weight per mt of the support and 23% of its st ructure was active biomass. Copyright (C) 1996 IAWQ.