Odour emission factors for assessment and prediction of Italian rendering plants odour impact

Among the industrial activities that may cause odour nuisance problems, rendering plants represent one of the most critical sources of smelly gaseous emissions and consequently of odour complaint. In this work, the odour emission factors (OEFs) for the rendering industry are determined based on experimental data obtained by means of dynamic olfactometry. An OEF is a representative value that relates the quantity of odour released to the atmosphere to a given associated activity. The odour emission factors were calculated to be equal to 4.52 × 108 ouE t−1 for process air, to 8.02 × 107 ouE t−1 for a mixture of process air and ambient air, and to 3.53 × 103 ouE t−1 for wastewater treatment tanks. Furthermore, the efficiencies of different odour abatement systems used for the treatment of different gaseous emissions from this kind of facility are evaluated and compared. The abatement efficiencies of the monitored odour reduction systems decrease passing from combustors (efficiencies over 99%) to biofilters (efficiencies between 73 and 80%) and scrubbers (efficiencies between 41 and 60%).