Fugitive dust emissions due to the disposal of dried red mud.

The recent change in the red mud storage practices poses a major concern with respect to the emission of suspended Particulate Matter (PM). With reference to a red mud tailing located in Sardinia, the article discusses the potential hazard of air pollution posed by the conversion of the disposal method from lagooning to dry disposal. A first estimation of airborne dust concentration for the two fractions PM10 and PM2,5 has been carried by means of a Gaussian atmospheric dispersion model, on the basis of the emission factors defined by US EPA. The results found for the long-term period (a calendar year) proved that the disposal of a dried residue does not pose relevant concern regarding air quality. As regard the PM10 short-term concentration, the possibility to exceed the limit value for more than 35 days in a calendar year can be avoided by adopting a work organization based on the use of wheel loaders of greater capacity.