The Technical Standard CETESB P2.111/2007 was tested to evaluate the microwave healthcare waste disinfection, by comparing the results obtained using the standard procedure, i.e. Bacillus atropheus spores in suspension inside vials distributed in the waste, with those obtained with spores dispersed on the particles surface. The experimental results were adjusted based on first-order kinetic model and Arrhenius Law to determine the activation energies (Ea) and the pre-exponential factors (k0). The Ea in spores suspension inside vials (99-45 J.mol-1) were significantly lower when compared with Ea (9,203-5,782 J.mol-1) from the inactivation of dispersed spores in the waste to k0 practically constant (0.26 and 0.23 min-1, respectively). Therefore, spore resistance to inactivation was greatly affected by the support medium used, since the spores were more susceptible to microwave exposition in liquid medium than in the solid one.
Bacillus atrophaeus; spores; inactivation; microwave; healthcare waste
