Phenolic refinery wastewater biodegradation by an expanded granular sludge bed reactor
Almendariz, F.J.; Meraz, M.; Olmos, A.D.; Monroy, O.
Water Science and Technology a Journal of the International Association on Water Pollution Research 52(1-2): 391-396
2005
ISSN/ISBN: 0273-1223 PMID: 16180455 Document Number: 593997
Refinery spent caustics (SC) were diluted with sour waters (SW) in a ratio 1:7, neutralized with CO2 (SC/SWCO2) 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 treated 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 gCOD L-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.