RESUMEN
This study compares sulfate-reduction performance in an anaerobic sludge with different carbon sources (ethanol, acetate, and glucose). Also, the toxic effect of copper was evaluated to assess its feasibility for possible acid mine drainage (AMD) treatment. Serological bottles with 1.5 g VSS/L and 150 mL of basal medium (0.67 g COD/g SO42- at a 7-8 pH) were used to determine the percentage of electron equivalents, maximum specific methanogenic (SMA), and sulfide generation activities (SGA). The copper effect was evaluated in a previously activated sludge in batch bioassays containing different concentrations of copper (0-50 mg/L), 3 gVSS/L, and 150 mL of basal medium (0.67 g COD/g SO42-). Carbon source bioassays with glucose obtained the best results in terms of the SGA (1.73 ± 0.34 mg S2-/g VSSâ¢d) and SMA (10.41 mg COD-CH4/g VSSâ¢d). The electron flow in the presence of glucose also indicated that 21.29 ± 5.2% of the metabolic activity of the sludge was directed towards sulfidogenesis. Copper toxicity bioassays indicated that a considerable decline in metabolic activity occurs above 10 mg/L. The 20%IC, 50%IC, and 80%IC were 4.5, 14.94, and 35.31 mg Cu/L. Compared to the other carbon sources tested, glucose proved to be a suitable electron donor since it favors sulfidogenesis. Finally, copper concentrations above 15 mg/L inhibited metabolic activity in the toxicity bioassays.
Asunto(s)
Carbono , Aguas del Alcantarillado , Anaerobiosis , Reactores Biológicos , Sulfatos/toxicidadRESUMEN
Refinery spent caustics (SC) were diluted with sour waters (SW) in a ratio 1:7, neutralized with CO2 (SC/SW(CO2)) and 83% of H2S was striped during this procedure, remaining an aromatic portion that contained 2123, 2730 and 1379 mg L(-1) of phenol, p-cresol and o-cresol, respectively. The mixture was teated anaerobically in an EGSB reactor fed with 1.5 gCOD L(-1) d(-1), without mineral supplements causing loss of COD removal efficiency that dropped to 23%, methane production ceased and no phenol or cresols were biodegraded. The EGSB experiments were resumed by feeding the reactor with nutrients and phenol at 1.0 gCOD L(-1) d(-1). The mixture SC/SWco2 added to the phenol load, was step increased from 0.10 to 0.87 gCODL(-1) d(-1) maximum. When total organic load was increased to 1.6, COD removal efficiency was 90% and at the highest load attained, 1.87, efficiency dropped to 23% attributed to the toxic effect produced by cresols.
Asunto(s)
Reactores Biológicos , Residuos Industriales , Petróleo , Fenoles/metabolismo , Eliminación de Residuos Líquidos/métodos , Bacterias Anaerobias/metabolismo , Biodegradación Ambiental , Dióxido de Carbono , Sulfuro de Hidrógeno , Metano/metabolismo , Aguas del AlcantarilladoRESUMEN
The degradation of of lineal alkylbenzene sulphonate (LAS) was studied in a two-stage anaerobic system where the acidogenic reactor was bioaugmented with a strain of Pseudomonas aeruginosa (M113). This is a strain, which under aerobic and denitrifying conditions uses LAS as carbon source. Results show that LAS was only degraded within the acidogenic stage while in the methanogenic reactor there was no degradation and eventually there was an inhibition due to a LAS accumulation in the sludge. During the experiment, the M113 strain remained in the acidogenic conglomerate (at around 10(4) CFU/mL) although there is no evidence of their involvement in LAS degradation.