Cleanup of industrial effluents containing heavy metals : a new opportunity of valorising the biomass produced by brewing industry

Heavy metal pollution is a matter of concern in industrialised countries. Contrary to organic pollutants, heavy metals are not metabolically degraded. This fact has two main consequences: its bioremediation requires another strategy and heavy metals can be indefinitely recycled. Yeast cells of Saccharomyces cerevisiae are produced at high amounts as a by-product of brewing industry constituting a cheap raw material. In the present work, the possibility of valorising this type of biomass in the bioremediation of real industrial effluents containing heavy metals is reviewed. Given the auto-aggregation capacity (flocculation) of brewing yeast cells, a fast and off-cost yeast separation is achieved after the treatment of metal-laden effluent, which reduces the costs associated with the process. This is a critical issue when we are looking for an effective, eco-friendly, and low-cost technology. The possibility of the bioremediation of industrial effluents linked with the selective recovery of metals, in a strategy of simultaneous minimisation of environmental hazard of industrial wastes with financial benefits from reselling or recycling the metals, is discussed

Research NoteAntioxidant activity of selected plants of the Great Fish River Reserve, Eastern Cape, South Africa

The Great Fish River Reserve (GFRR), in the Eastern Cape, has proved to be particularly suitable for the black rhinoceros that have been introduced over the past 20 years. In captivity, these animals often suffer from a number of disease conditions, certain of which may be related to antioxidant deficiencies in their diet. Therefore, the antioxidant capacities of the leaves of 25 bush species in the GFRR was determined by the DPPH, ABTS and FRAP methods and the total phenolics by the Folin-Ciocalteau procedure. The plant species Ozoroa mucronata, Putterlickia pyracantha, Phyllanthus verrucosus, Maytenus capitata, Euclea undulata and Jatropha capensis were found to have the highest antioxidant capacity by the three methods, whereas for total phenols Putterlickia pyracantha was replaced in the top six by Carissa bispinosa. The black rhinoceros in this area appear to favour plants of varying antioxidant capacity and do not seem to select browse species for this property.African Journal of Range & Forage Science 2010, 27(2): 109–11

Selective recovery of chromium, copper, nickel, and zinc from an acid solution using an environmentally friendly process

PURPOSE: Real electroplating effluents contain multiple metals. An important point related with the feasibility of the bioremediation process is linked with the strategy to recover selectively metals. In this work, a multimetal solution, obtained after microwave acid digestion of the ashes resulted from the incineration of Saccharomyces cerevisiae contaminated biomass, was used to recover selectively chromium, copper, nickel, and zinc. RESULTS: The acid solution contained 3.8, 0.4, 2.8, and 0.2 g/L of chromium(III), copper, nickel, and zinc, respectively. The strategy developed consisted of recovering copper (97.6%), as a metal, by electrolyzing the solution at a controlled potential. Then, the simultaneous alkalinization of the solution (pH 14), addition of H(2)O(2), and heating of the solution led to a complete oxidation of chromium and nickel recovery (87.9% as a precipitate of nickel hydroxide). After adjusting the pH of the remaining solution at pH 10, selective recovery of zinc (82.7% as zinc hydroxide) and chromium (95.4% as a solution of cromate) was achieved. CONCLUSION: The approach, used in the present work, allowed a selective and efficient recovery of chromium, copper, nickel, and zinc from an acid solution using a combined electrochemical and chemical process. The strategy proposed can be used for the selective recovery of metals present in an acid digestion solution, which resulted from the incineration of ashes of biomass used in the treatment of heavy metals rich industrial effluents.The authors thank to the Fundacao para a Ciencia e a Tecnologia (FCT) from Portuguese Government for the financial support of this work with FEDER founds, by the Project POCTI/CTA/47875/2002. Manuela D. Machado is also gratefully acknowledged for a grant scholarship financed under the same project and the grant from FCT (SFRH/BD/31755/2006)

Bioremediation of industrial effluents containing heavy metals using brewing cells of Saccharomyces cerevisiae as a green technology : a review

The release of heavy metals into the environment, mainly as a consequence of anthropogenic activities, constitutes a worldwide environmental pollution problem. Unlike organic pollutants, heavy metals are not degraded and remain indefinitely in the ecosystem, which poses a different kind of challenge for remediation. It seems that the "best treatment technologies" available may not be completely effective for metal removal or can be expensive; therefore, new methodologies have been proposed for the detoxification of metal-bearing wastewaters. The present work reviews and discusses the advantages of using brewing yeast cells of Saccharomyces cerevisiae in the detoxification of effluents containing heavy metals. The current knowledge of the mechanisms of metal removal by yeast biomass is presented. The use of live or dead biomass and the influence of biomass inactivation on the metal accumulation characteristics are outlined. The role of chemical speciation for predicting and optimising the efficiency of metal removal is highlighted. The problem of biomass separation, after treatment of the effluents, and the use of flocculent characteristics, as an alternative process of cell-liquid separation, are also discussed. The use of yeast cells in the treatment of real effluents to bridge the gap between fundamental and applied studies is presented and updated. The convenient management of the contaminated biomass and the advantages of the selective recovery of heavy metals in the development of a closed cycle without residues (green technology) are critically reviewed.The authors thank to the Fundacao para a Ciencia e a Tecnologia (FCT) from Portuguese Government for the financial support of this work with FEDER founds, by the Project POCTI/CTA/47875/2002 and through the grants PEST-OE/EQB/LA0023/2011 (IBB) and PEST-C/EQB/LA0006/2011 (REQUIMTE)

Background radiation measurements at high power research reactors

Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including γ-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the background fields encountered. The general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein

Background radiation measurements at high power research reactors

Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including γ-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the background fields encountered. The general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein