Interactions of toluene and p-xylene in air treatment biofilters packed with an inert filter media were
studied. The effect of the inlet load of toluene, p-xylene and mixtures of both compounds on the biodegradation
rate was analyzed in three lab-scale biofilters. A maximum elimination capacity (EC) of 26.5 and
40.3 g C m3 h1 for an inlet load (IL) of 65.6 and 57.8 g C m3 h1 was obtained for p-xylene and toluene
biofilters, respectively. Inhibition of p-xylene biodegradation by the presence of toluene took place when
the mixture was treated, whereas the presence of p-xylene had an enhancing effect on the toluene
removal efficiency. Specific growth rates (l) from 0.019 to 0.068 h1 were calculated in the mixed biofilter,
where the highest values were similar to mixtures with lower p-xylene levels (ILp-Xyl
8.84 ± 0.29 g C m3 h1). Michaelis–Menten and Haldane type models were fitted to experimental EC
for p-xylene and toluene biofilters, respectively