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The purpose of this research was to improve a process for the removal of Cd and Pb from municipal incinerator fly ashes (boiler and electrofilter ashes). The first part of this study was to evaluate the optimum conditions for Pb extraction using alkaline washing steps. The tests carried out with various ash solid concentrations (10–50% (w/v)) have shown better Pb removal yields following the decrease of the solid concentrations. Nevertheless, by considering the economic aspect, a ratio of 30% (w/v) was retained as the optimal condition for alkaline leaching steps. A very short contact time (2 min) allows a maximum lead solubilization during alkaline washings. A series of two or three alkaline washing steps is necessary for sufficient lead removal. Once the alkaline leaching conditions have been optimized, research was applied to identify the optimum conditions of acid leaching. Best Pb and Cd removal yields of 25% and 85%, respectively, have been obtained by using two 30-min washing steps at pH 3 with a pulp density of 10% (w/v). The treated ashes respect the TCLP criteria. Finally, the adapted process of ash treatment presented in this study allows a substantial reduction of 57% of the chemical costs compared with the conventional procedure, and a significant reduction (83%) of water consumption. [ABSTRACT FROM AUTHOR]

Abstract: Aim of the study: This study has examined the sensitivity of a commercially available fluorochrome stain, the Fluo-RAL kit (RAL), in comparison to the Degommier''s stain as gold standard. Materials and methods: Hundred and thirty-three twin smears, made directly from samples or after their decontamination with N-acetyl-L-cysteine NaOH, were stained, the first slide with the Degommier''s method and the second with the Fluo-RAL kit. The samples were 58 sputums, 31 broncho-aspirations, nine gastric lavages, 11 bronchoalveolar lavages, six pleural fluids, two cerebro-spinal fluids, 11 biopsies, two blood cultures and two deep pus. They were examined with 400 × objective under standard fluorescence UV filter by two laboratory technicians independently. The results were expressed with semi-quantitative mean from 0 to 4+. Results: Hundred and thirty-two results were agreed in grading between the two methods: 73 negative smears, nine quantified as rare (1+), 11 as few (2+), 32 as moderate (3+) and seven as numerous (4+). The only discrepant result had concerned a positive smear quantified as 1+ with the Degommier''s stain and as 2+ with the Fluo-RAL kit. This discrepancy was confirmed after a second examination. Conclusion: After this study, the Fluo-RAL kit was considered as agreed for its daily use in our laboratory. It improves the standardisation of fluorescence microscopy without additional cost or waste of time and reduces the chemical risk in the laboratory. This test, associated with reading using light-emitting diodes, could allow the development of fluorescence microscopy, the higher sensitive method for direct diagnosis of tuberculosis, in poor-resource countries where tuberculosis is a public health problem. [Copyright &y& Elsevier]