BIODEGRADATION OF 2,4-DICHLOROPHENOL IN AN AEROBIC REACTOR

摘要

The aim of this work was the bioremediation of 2,4-dichlorophenol (2,4-DCP), in order to accomplish the current national legislation for this type of discharges (minimum quality objective of 20 μg/l). An experiment was performed in a 3-1 continuous aerobic reactor with an hydraulic retention time (HRT) of 4 hours, using a pure culture strain of Ralstonia basilensis DSM 11853~T as the inoculum, under non-sterile conditions. The study was carried out in the presence of other competitive carbon sources, using a synthetic sewage to feed the reactor, thus simulating a real wastewater. The 2,4-DCP concentrations in the reactor inlet and clarifier outlet were analysed by solid phase micro-extraction (SPME), followed by gas chromatogra-phy using an electron capture detector (ECD). The results demonstrated that 2,4-DCP treatment efficiency was 90.1%, 79.5% and 84.1% for feed concentrations of 1000, 500 and 200 μg/l, respectively. Removal of organic matter was evaluated by the chemical oxygen demand (COD), and an average COD removal of 62.4% was achieved for an average COD feeding of 187 mg O_2/l. The results of this work suggest that 2,4-DCP can be degraded by micro-organisms, and are promising in the sense of using this system for the cleanup of real wastewaters.