BIODEGRADATION OF PENTACHLOROPHENOL IN AN AEROBIC REACTOR

摘要

Chlorophenols are considered to be priority pollutants by both the United States Environmental Protection Agency (US-EPA) and the European Union (EU), due to their high toxicity and mutagenic and carcinogenic properties. Therefore, the need arises to evaluate the biodegradation of pen-tachlorophenol (PCP), present in wastewaters in low concentrations (below 1 mg/l), and in the presence of other competitive carbon sources, in order to meet the demands of the current legislation for this type of discharges. An experiment was carried out with a 3-L continuously activated sludge reactor (hydraulic retention time of 4 h) using soil as the inoculum. The PCP concentration was analyzed by solid phase micro-extraction (SPME), followed by gas chromatography using an electron capture detector (GC/ECD). Chemical Oxygen Demand (COD) and optical density at 610 nm were also analyzed. The results show that 33 days after feeding the reactor with a synthetic sewage containing all the nutrients to its operation and PCP at a level of 106.3 μg/L, the PCP removal stabilized in an average result of 51.1%. For a 200 μg/L feed, no PCP removal was observed within the experimental period. The average COD removal in the reactor during this work was 65.5%, for an average COD feed of 189 mg/L.