Toluene removal by biofiltration: Influence of the nitrogen concentration on operational parameters : Novel reactor engineering for the new millennium

This study dealt with the operation of a laboratory-scale upflow biofilter, packed with compost-based filter material. The airborne contaminant studied was toluene, maintained at a constant inlet concentration of 1.7 g/m 3 . The input air was conveyed upward through the filter column at a flow rate of 1 m 3 /h. The objective of this work was the study of the impact of increasing concentrations of nitrogen contained in the nutrients solution and, hence, the establishment of a new correlation between this parameter and the overall degradation performance. Depending on the nitrogen concentration employed, two biodegradation regimes have been identified. Over the optimal range of nitrogen concentrations (2.0-8.0 g of N/L), the maximum level of elimination capacity achieved was 100 g/m 3 .h. This value is in line with theoretical considerations that suggest that an optimal nitrogen concentration of ≃2.6 g of N/L is required to achieve the same performance (100 g/m 3 .h).