Abstract: “A soil biofilter, with internal gas recycle and a suction cell, was used in this study to investigate the influence of nutrient addition on the volumetric removal rates of toluene (as air contaminant) and on the concomitant carbon dioxide production. The use of a suction cell allowed water content control and uniform distribution of nutrients throughout the filter bed medium. Nutrient addition increased the elimination capacity by about five times upon the second addition of nitrate as nitrogen source and the subsequent addition of micronutrients. However, this resulted to the formation of a gelatinous substance in the soil bed. This study gives evidence that calcium accumulation in biofilms plays a significant role in cross-linking extracellular polymeric substances (EPS), components that may affect long-term operation of the biofiltration system. Adding nutrients and maintaining their concentrations at a level that contributes favorably to biofiltration performance continues to be a”

Keywords: biofiltration, nutrient, air pollution control, elimination capacity