Toluene Removal by Biofiltration: Influence of the Nitrogen Concentration on Operational Parameters

Abstract

The study presented in this paper 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 m3·h-1. 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-1], the maximum level of elimination capacity achieved was ≃100 g·m-3·h-1. This value is in line with theoretical considerations that suggest that an optimal nitrogen concentration of ≃2.6 g of N·L-1 is required to achieve the same performance (100 g·m-3·h-1).