Evaluation of co-metabolic removal of trichloroethylene in a biotrickling filter under acidic conditions

This study investigated the removal of hydrophobic trichloroethylene (TCE) in the presence of methanol (co-metabolite) in a biotrickling filter, which was seeded with fungi at pH 4. Starvation was chosen as the biomass control strategy. Two systems, Biofilter I (methanol:TCE 70:30) and Biofilter II (methanol:TCE 80:20) were run in parallel, each with varying composition ratios. The TCE loading rates for both biofilters ranged from 3.22 to 12.88 g/m³/hr. Depending on the ratio, methanol concentrations varied from 4.08 to 27.95 g/m³/hr. The performance of the systems was evaluated and compared by calculating removal kinetics, carbon mass balance, efficiencies and elimination capacities. Methanol was observed to enhance TCE removal during the initial loading rate. However, methanol later inhibited TCE degradation above 6.44 g TCE/m³/hr (Biofilter I) and 3.22 g TCE/m³/hr (Biofilter II). Conversely, TCE did not impede methanol removal because over 95% methanol elimination was consistently achieved. Overall, Biofilter I was able to outperform Biofilter II due to its greater resistance towards methanol competition.