Biodegradability of commercial and weathered diesel oils

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aerobic biodegradation of butanol and diesel oil blends

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo da oxidação dos sulfetos sintéticos molibdenita (MoS2) e covelita (CuS) por Acidithiobacillus ferrooxidans via respirometria celular

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thiobacillus ferrooxidans response to copper and other heavy metals: growth, protein synthesis and protein phosphorylation

Respirometric experiments demonstrated that the oxygen uptake by Thiobacillus ferrooxidans strain LR was not inhibited in the presence of 200 mM copper. Copper-treated and untreated cells from this T. ferrooxidans strain were used in growth experiments in the presence of cadmium, copper, nickel and zinc. Growth in the presence of copper was improved by the copper-treated cells. However, no growth was observed for these cells, within 190 h of culture, when cadmium, nickel and zinc were added to the media. Changes in the total protein synthesis pattern were detected by two-dimensional polyacrylamide gel electrophoresis for T. ferrooxidans LR cells grown in the presence of different heavy metals. Specific proteins were induced by copper (16, 28 and 42 kDa) and cadmium (66 kDa), whereas proteins that had their synthesis repressed were observed for all the heavy metals tested. Protein induction was also observed in the cytosolic and membrane fractions from T. ferrooxidans LR cells grown in the presence of copper. The level of protein phosphorylation was increased in the presence of this metal.

Oxidative dissolution of covellite by Thiobacillus ferrooxidans

Oxidation of research-grade covellite was investigated in respirometric and growth experiments with Thiobacillus ferrooxidans. Covellite was directly oxidized by T. ferrooxidans in respirometric experiments, but the pH of mineral salts medium increased to prohibitively high values because of high sulfide concentrations. In glycine-H 2SO 4 buffered medium the pH remained steady and the oxygen uptake activity of T. ferrooxidans was not inhibited. In cultures growing with covellite as the sole source of energy, the pH increased to about 4. Redox potential increased to 500-600 mV during bacterial oxidation of covellite in the presence and absence of additional Fe 2+, whereas it remained mostly at about 350 mV in abiotic control. Jarosite was a major solid-phase product in T. ferrooxidans cultures. The solubilization of copper from covellite in inoculated flasks was higher than that obtained in control flasks and was not enhanced in the presence of additional Fe 2+.The sample also contained bornite (Cu 5FeS 4) which released iron in solution under all experimental conditions. Accumulation of S 0 was apparent only in inoculated covellite samples. © 1997 Elsevier B.V. All rights reserved.

Oxidative dissolution of chalcopyrite by Thiobacillus ferrooxidans

The oxidative dissolution of research-grade chalcopyrite was characterized in respirometric and growth experiments with Thiobacillus ferrooxidans. In respirometric experiments with chalcopyrite, the pH of mineral salts medium increased to values that inhibited the oxygen uptake activity of T. ferrooxidans. In glycine-H 2SO 4 buffered medium the pH remained stable and oxygen uptake was not inhibited. In cultures growing with chalcopyrite as the sole source of energy, pH changes were only minor during the incubation. The redox potential values increased to about 600 mV during the bacterial oxidation of chalcopyrite in the presence and absence of additional Fe 2+, while they remained at about 350 mV in abiotic control flasks. Iron in chalcopyrite was solubilized and oxidized to Fe 3+ by T. ferrooxidans. In the abiotic controls, by comparison, less iron was solubilized and it remained as Fe 2+. Jarosite was a major solid- phase product in T. ferrooxidans cultures. The solub'flization of copper from chalcopyrite in inoculated flasks was enhanced in the presence of additional Fe 2+.Accumulation of S 0, reflecting partial oxidation of the S-entity of chalcopyrite, was apparent from the x-ray diffraction analysis of solid residues from the inoculated flasks as well the abiotic controls. © 1997 Elsevier B.V. All rights reserved.

Avaliação do potencial de biorremediação de solos e de águas subterrâneas contaminados com óleo diesel

Pós-graduação em Geociências e Meio Ambiente - IGCE

Respirometric techniques for assessment of biological kinetics in constructed wetland

The aim of this research was the development of a procedure to measure biological kinetics of organic matter oxidation and nitrification in constructed wetland, by using respirometric techniques. Columns simulating cores of vertical subsurface flow systems were investigated. The oxygen uptake rate (OUR) of the columns was calculated on the basis of the difference of DO concentrations measured continuously at the top and at the bottom of the column. From the respirogram, the following kinetic parameters have been evaluated: maximum rate of oxidation of readily biodegradable COD, maximum rate of nitrification, endogenous respiration of the biomass grown inside the bed. In order to improve the interpretation of the respirograms, additional respirometric tests were carried out on the wetland columns by using pure substrates, such as acetate (carbon source) and ammonium (substrate for nitrification). The kinetic parameters obtained from respirograms can be useful for control and design of constructed wetlands or for improving nutrient and carbon mass balances.

Some experiments with high order compact methods using a computer algebra software - Part I

We consider a procedure for obtaining a compact fourth order method to the steady 2D Navier-Stokes equations in the streamfunction formulation using the computer algebra system Maple. The resulting code is short and from it we obtain the Fortran program for the method. To test the procedure we have solved many cavity-type problems which include one with an analytical solution and the results are compared with results obtained by second order central differences to moderate Reynolds numbers. (c) 2005 Elsevier B.V. All rights reserved.

Some experiments with high order compact methods using a computer algebra software - Part II (non-uniform grid)

We generalize a procedure proposed by Mancera and Hunt [P.F.A. Mancera, R. Hunt, Some experiments with high order compact methods using a computer algebra software-Part 1, Appl. Math. Comput., in press, doi: 10.1016/j.amc.2005.05.015] for obtaining a compact fourth-order method to the steady 2D Navier-Stokes equations in the streamfunction formulation-vorticity using the computer algebra system Maple, which includes conformal mappings and non-uniform grids. To analyse the procedure we have solved a constricted stepped channel problem, where a fine grid is placed near the re-entrant corner by transformation of the independent variables. (c) 2006 Elsevier B.V. All rights reserved.

Stochastic dynamics in exotic and native blowflies: an analysis combining laboratory experiments and a two-patch metapopulation model

In this study we explored the stochastic population dynamics of three exotic blowfly species, Chrysomya albiceps, Chrysomya megacephala and Chrysomya putoria, and two native species, Cochliomyia macellaria and Lucilia eximia, by combining a density-dependent growth model with a two-patch metapopulation model. Stochastic fecundity, survival and migration were investigated by permitting random variations between predetermined demographic boundary values based on experimental data. Lucilia eximia and Chrysomya albiceps were the species most susceptible to the risk of local extinction. Cochliomyia macellaria, C. megacephala and C. putoria exhibited lower risks of extinction when compared to the other species. The simultaneous analysis of stochastic fecundity and survival revealed an increase in the extinction risk for all species. When stochastic fecundity, survival and migration were simulated together, the coupled populations were synchronized in the five species. These results are discussed, emphasizing biological invasion and interspecific interaction dynamics.

Electrolytic treatment applied to the industrial effluent containing persistent wastes monitored by Bartha respirometric assays

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aerobic biodegradation of butanol and gasoline blends

This work aimed to assess the aerobic biodegradation of butanol/gasoline, blends (5; 10; 15 and 20% v/v), being the latter compared to the ethanol/gasoline blend (20% v/v). Two experimental techniques were employed, namely the respirometric method and the redox indicator DCPIP test. in the former, experiments simulating the contamination of natural environments (addition of 50 mL of fuel kg(-1) of soil from a non-contaminated site and 20 mL of fuel L(-1) of water from a river) were carried out in biometer flasks (250 mL), used to measure the microbial CO(2) production. The DCPIP test assessed the capability of four inocula to biodegrade the blends of 20%. The addition of butanol at different concentrations enhanced the biodegradation of gasoline in soil. However, no practical gains were observed for concentrations of butanol above 10%. Ethanol showed to have a much faster biodegradation rate than butanol, particularly in water, and the following order of biodegradability was found: ethanol > butanol > gasoline. The addition of the alcohols to the gasoline resulted in positive synergic effects on the biodegradation of the fuels in soil and water matrices. Furthermore, results suggest that, in soil, butanol better enhanced the biodegradation of gasoline than ethanol. (C) 2009 Elsevier Ltd. All rights reserved

Complementarity of eastern and western hemisphere long-baseline neutrino oscillation experiments

We present a general formalism for extracting information on the fundamental parameters associated with neutrino masses and mixings from two or more long baseline neutrino oscillation experiments. This formalism is then applied to the current most likely experiments using neutrino beams from the Japan Hadron Facility (JHF) and Fermilab's NuMI beamline. Different combinations of muon neutrino or muon anti-neutrino running are considered. The type of neutrino mass hierarchy is extracted using the effects of matter on neutrino propogation. Contrary to naive expectation, we find that both beams using neutrinos is more suitable for determining the hierarchy provided that the neutrino energy divided by baseline (E/L) for NuMI is smaller than or equal to that of JHF, whereas to determine the small mixing angle, theta(13), and the CP or T violating phase delta, one neutrino and the other anti-neutrino are most suitable. We make extensive use of bi-probability diagrams for both understanding and extracting the physics involved in such comparisons.

Method for determination of vertical bar U(e)3 vertical bar in neutrino oscillation appearance experiments

We point out that determination of the MNS matrix element \U-e3\ = s(13) in long-baseline nu(mu) --> nu(e) neutrino oscillation experiments suffers from large intrinsic uncertainty due to the unknown CP violating phase delta and sign of Deltam(13)(2). We propose a new strategy for accurate determination of theta(13); tune the beam energy at the oscillation maximum and do the measurement both in neutrino and antineutrino channels. We show that it automatically resolves the problem of parameter ambiguities which involves delta, theta(13), and the sign of Deltam(13)(2). (C) 2002 Elsevier B.V. B.V. All rights reserved.