Full text
| |
| Author(s): |
Sílvia Helena Saboya Arruda Fatibello
Total Authors: 1
|
| Document type: | Master's Dissertation |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD) |
| Defense date: | 2001-01-19 |
| Examining board members: |
Rosana Filomena Vazoller;
Maria do Carmo Calijuri;
Marcia Helena Rissato Zamariolli Damianovic
|
| Advisor: | Rosana Filomena Vazoller |
| Abstract | |
This MSc Thesis work describes the study of the capacity of trichloroethylene (TCE) degradation by the activity of two biological sludges, under strict anaerobic conditions at thermophilic and mesophilic temperatures. In the first study, it was used an anaerobic granular sludge from an upflow anaerobic sludge blanket (UASB) operated under thermophilic conditions (55 ± 2 °C) for the vinasse treatment. After sampling and methanogenic activation of this sludge, the consortium of methanogenic cultures was enumerated using the Most Probable Number (NMP) in the following sources of carbon: glucose, sodium formiate, sodium lactate/sodium sulfate, methanol, sodium acetate/sodium sulfate, sodium propionate, sodium butyrate, H2/C02, glycerol, sodium propionate and sodium acetate, under atmosphere of N2/C02. The largest cellular concentration of 1.6 x 109 cells of NMP/ml was found in the 1O mmoles/L glucose solution. For the methanogenics, the best cellular growth was in 1 0% v/v H2/C02 with cellular concentration of 3.9 x 107 cells of NMP/mL lt was identified some genus such as the Methanobacterium sp, Methanosarcinas sp, Methanococcus sp and Methanosaeta sp. In addition, it was also observed members of some genera such as Desulfotomaculum sp and Desulfobacter sp. Than, the TCE degradation studies (5mg TCE/g of STV) were carried out using the thermophilic sludge in the Zinder\'s mineral medium with the following carbon sources such as sodium acetate, sodium propionate, sodium butyrate, glucose, sodium lactate, sodium sulfate, methanol and yeast in nine flask- reactors, under 150 rpm and 55 ± 2 °C. The biodegradation of this chlorinated compound was made by monitoring methane concentration in the headspace and TCE remaining concentration in the reactional medium, using gas chromatography, for 34 days. In this period, there were 30% and 85% of abiotic and biotic TCE degradation, respectively, showing thus the ability of this thermophilic sludge to biodegrade this chlorinated solvent. A second NMP enumeration done after the TCE degradation, confirmed a larger cells concentration for the glucose source of 2.6 x 107 cells of NMP/ml and for the methanogenic enumeration a 6.8 x 106 cells of NMP/ml in the H2/C02 source. In this second enumeration there was rod Methanobacterium sp predominancy. A decrease of Methanosarcína sp was observed. In the second study, a Represa do Lobo (Broa) mesophilic sediment was used, which after collection and methanogenic activation, the NMP enumeration of the microbial consortium was made with the following organic sources: sodium formiate, sodium lactate, methanol, sodium acetate and ethanol under atmosphere of N2/C02. The largest cells concentration of 4.5 x 107 cells of NMP/ml was found in the 20 mmoles/L sodium lactate solution. For the methanogenics, the best cellular growth of 5.6 x 103 cells of NMP/ml was obtained in 20 mmoles/L sodium formiate solution. lt was identified some genus such as Metanobacteríum sp, Methanosarcínas sp and Methanosaeta sp. Rods of the Desulfovíbrío sp and Desulfobu/bus sp genus were also observed. In the study of the TCE degradation it was employed a concentration of 5mg TCE!g of STV, this mesophilic sediment in the Zinder\'s medium with the following carbon sources: sodium acetate, sodium butyrate, sodium lactate, sodium formiate, methanol and ethanol in nine flask-reactors, under 200 rpm and for 25 .:!: 2 °C. The biodegradation of this chlorinated substance was made monitoring the methane concentration in the headspace and the remaining TCE concentration in the medium, using gas chromatography, for 48 days. In this period there were an abiotic and biotic TCE degradation of 23% and 79%, respectively, showing the ability of the mesophilic sludge to biodegrade this chlorinate solvent. After this degradation, a second NMP enumeration was carried out and a concentration of 3.0 x 107 cells of NMP/ml in 20 mmoles/L sodium lactate was found; and for the methanogenics a cells concentration of 1.1 x 1 06 cells of NMP/ml was observed in the same carbon source. lt was observed in this second NMP enumeration a prevalence of Methanosarcina sp and Methanobacteríum sp and in the fluorescence it was observed an increase of the microorganisms diversity. (AU) | |