Start-up, performance and optimization of a compost biofilter treating gas-phase mixture of benzene and toluene

• Compost biofilter was exposed to steady and transient state operations.
• Maximum elimination capacity was 91.2 g/m3 h at a total inlet load of 150.2 g/m3 h.
• The presence of toluene inhibited benzene removal strongly at higher loading rates.
• Main effects of process variables were statistically significant with low P values.
• After prolonged periods of starvation, the biofilter was able to convalesce.

The performance of a compost biofilter inoculated with mixed microbial consortium was optimized for treating a gas-phase mixture of benzene and toluene. The biofilter was acclimated to these VOCs for a period of ∼18 d. The effects of concentration and flow rate on the removal efficiency (RE) and elimination capacity (EC) were investigated by varying the inlet concentration of benzene (0.12–0.95 g/m3), toluene (0.14–1.48 g/m3) and gas-flow rate (0.024–0.072 m3/h). At comparable loading rates, benzene removal in the mixture was reduced in the range of 6.6–41% in comparison with the individual benzene degradation. Toluene removal in mixture was even more affected as observed from the reductions in REs, ranging from 18.4% to 76%. The results were statistically interpreted by performing an analysis of variance (ANOVA) to elucidate the main and interaction effects.

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