Fine particle collection performance of a glass microfiber filtering unit as tail end device polishing flue gas from waste incineration

Fine particles are associated with varied health impacts and mutagenic activity and have recently emerged among the most important pollutants worldwide in terms of human health. Anthropogenic sources of fine particles include mainly industrial combustion processes, then the availability of advanced techniques to efficiently remove them from exhausts becomes an essential topics for the associated health risk reduction. Waste incinerators represent certainly a minor source of fine particles if they apply Best Available Techniques, but technical improvements to decrease ultrafine particle number concentration in flue gas are required to upgrade the social acceptance of these plants. The present paper provides the results of an experimental investigation on a pilot scale filtering system installed on the industrial waste incinerator "Ecolombardia 4" located in Filago (BG), in the northern of Italy, downstream of the Air Pollution Control Devices except the final fabric filter, to decrease particle emission below 50 μg/m 3 (11% vol O 2, dry gas). The pilot plant combined a fabric filter with bags made of PTFE with a PTFE membrane with a filtering system of glass microfibers respectively as a second and a third stage of filtration (the first dedusting unit was the early stage electrostatic precipitator of the industrial plant).The pilot filtering system allowed to abate the total dust emission around 27-38 μg/m 3 (11% vol O 2, dry gas) or 3,8x10 2-5,5x10 2 particle/cm3, registering a filtering efficiency of submicron particles respectively of 75% (mass) and 67% (number). The comparison with similar plants shows the potentiality of the microfiber glass filtering unit to be used as a final polishing device for submicron particle effective reduction in waste incinerator flue gas.