A hazardous solid waste is accumulated during the processing of tobacco for the manufacture of cigarettes. Its main characteristics are the high nicotine content as the only toxic compound, and the powdery structure that does not permit recycling. A biotechnological process is proposed to detoxify these powdery tobacco residues. The toxic compound, nicotine, is transferred from the solid phase to an aqueous solution through efficient percolation. Nicotinophilic micro-organisms were screened to evaluate their ability to degrade nicotine directly in the extracted liquid. The biodegradation process was followed by nicotine detection and CO 2 production, while other parameters were determined to assess the correct disposal of the final products. Among three strains used, Pseudomonas putida had the best nicotine degradation performance in this complex medium. © 1997 ISWA

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Legionella spp . are considered an important cause of potentially preventable morbidity and mortality, making environmental surveillance a crucial component of risk assessment plans. In this work, 20,319 water samples were collected in 3,983 environmental surveys during a 16-year period by ARPA, the Regional Agency for Environmental Protection, Friuli Venezia Giulia, and the results were studied to better understand the diffusion mechanisms of Legionella . The data showed a strong seasonal signal, a prevalence of L. pneumophila serogroup 2–15 in most environments (63% of positive samples), a prevalence of L. pneumophila serogroup 1 in swimming pool-associated environments (82% of positive samples), a persistent presence of Legionella in hospitals and a recurrent presence of Legionella in other facilities such as hotels, possibly years after interventions, highlighting the difficulty of eradicating the bacteria. Retrospective spatio-temporal analyses on geocoded historical data were carried out with SaTScan using an ordinal model with risk as a covariate to identify potential clusters with an excess of cases in the higher-risk categories. Although no outbreaks occurred during the period of study, such analyses identified spatially restricted zones with unusual contamination, which sometimes were also areas in which several surveys triggered by notifications of clinical cases were performed. Simulations of periodic prospective analyses permitted the assessment of the efficacy of the method in early detection of such clusters. The proposed method may be a useful tool in environmental surveillance, prevention and control of Legionella .

M . C IV I LI NI , M. DE B ER TO L DI AN D G. TE L L. 1999.Three naphthalene-degrading strains were isolated from compost, characterized by morphological and physiological properties and differentiated by 16S rDNA RFLP. During growth on naphthalene, Pseudomonas aeruginosa 2NR produced ortho catechol pathway intermediates and gentisic acid. The ability to accumulate and degrade gentisic acid shows that Ps. aeruginosa 2NR has a different salicylate pathway to that of the intensely studied Ps. putida NCIB 9816. Molecular analysis showed the presence both of genes of the upper naphthalene pathway and genes of the ortho and meta catechol pathways. The insertion of nagH and nagG, coding for salicylate 5-hydroxylase in Pseudomonas sp. U2, was absent in Ps. aeruginosa 2NR, as in Ps. putida NCIMB 9816.

A new strategy for composting has been developed, based on O2 feedback control. Experiments were carried out on composting the biodegradable fraction of municipal solid waste in a closed bioreactor, aerated by pressure ventilation. Ventilation was controlled in order to maintain the O2 level in the internal atmosphere of the composting mass between 15 and 20%. The new strategy seems to give satisfactory results in terms of process control, quality of end-product, low energy consumption, and hygienization of compost. These results were supported by analyses of: (1) the variation of the main microbial groups during composting; (2) the balance of material; (3) the gas present in the internal atmosphere (O2, NH3, CO2, H 2S); (4) phytotoxicity; and (5) pathogenic and indicator micro-organisms. The importance of carrying out these analyses to guarantee the quality of the end-product and to control the process is discussed. Finally, the new system for controlling composting is compared with the existing strategies (Beltsville and Rutgers systems).