Abatement and bio-digestion of airborne contamination in precision mechanics: the case study of Beretta firearms

The precision machining represent a crucial step of firearm production and it has, in general, a number of critical environmental issue related to the specific processing. For about four months, an Immobilized cell bioreactors system (Bonoli et al., 2014; Borkowski 1995; Lakhwala et al. 1991) has been installed within the rifle barrel reaming area of the Beretta plant for containment of the contamination caused by specific processing involved. Although the levels of contamination arising from emulsions used for the reaming process of the gun barrels and metal dust deriving from it proved to remain already within the limits of the law, remarkable abatements of several airborne contaminants have been detected. The improvement of indoor environment was confirmed both by impressions of the staff and analysis performed on indoor air quality and process water of the system, carried out on the basis of standard procedures for industrial hygiene by an independent laboratory.Oil mist concentration, for instance, decreased for about 40% of baseline in the air. Volatile Organic Compounds were brought to levels below the detection limit of the portable Photoionizer used. Residual inert dust, captured and biodegraded by the system, was found in bioreactors, in concentration up to 1700 mg/L of iron in water, for a total quantity of about 885 g during the whole testing period. Considering the critical issues related to the production of firearms for sports use, the application of this technology appears to be particularly suitable for containment of carcinogens airborne contamination, such as walnut wood for the production of gunstock (Chemotti, 2002).