[Biodegradation of benzene series compounds under nitrate reducing conditions].

A series of batch experiments were performed using mixed bacterial culture to investigate the biodegradability of benzene, toluene, ethylbenzene and the xylene isomers (BTEX) under denitrifying conditions. The results show that BTEX can be degraded effectively by the mixed bacterial culture. The biodegradation of BTEX could be modeled by the substrate inhibition Monod equation. When the concentrations of BTEX were less than 50 mg x L(-1), the anaerobic degradation rates decreased with toluene > ethylbenzene > m-xylene > o-xylene > p-xylene > benzene. The ratio between the amount of nitrate consumed and the amount of the benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene degraded was 9.47, 9.26, 11.14, 12.46, 13.36 and 13.02, respectively. The electron acceptor needed in the initial anaerobic degradation of BTEX was nitrate, and then both nitrate and nitrite could be served as the electron acceptors for the further degradation of the intermediates of BTEX.