覆膜态Fe(OH)_3在厌氧条件下生物降解苯和甲苯的初探

Anoxic biodegradation of benzene and toluene in the presence of Fe(OH)_3-coated sand

天然条件下氯代烃的污染经常会与石油烃的污染共存,对于这种混合污染羽的治理,第一步采用粒状铁还原氯代烃,后续利用微生物和第一步产生的副产物生物降解石油烃。苯系物是石油烃中毒性较大、存留时间较长的污染物,本文利用批实验的方法研究了厌氧条件下用Fe(OH)3覆膜于石英砂表面的Fe(Ⅲ)作为电子受体降解苯和甲苯。结果表明,Fe(Ⅲ)作为电子受体时苯和甲苯能够发生厌氧生物降解,经过驯化后苯和甲苯的降解速度明显加快。降解实验表明甲苯的降解速度比苯的降解速度快,苯降解的半衰期是4.02d,甲苯降解的半衰期是3.81d。

Petroleum hydrocarbon and chlorinated hydrocarbon multi-plumes usually coexist under nature conditions. The disposal of the contaminated plume is focused on the utilization of the products from granular iron permeable reactive barriers （PRBs） which can remove chlorinated hydrocarbons as the electron acceptor to biodegrade BTEX in the aquifer. Benzene and toluene are the most toxic compounds and tend to exist for a long time in the aquifer. This study focused on the biodegradation of benzene and toluene by using Fe（ Ⅲ ） from the Fe（OH）3-coated sand under anoxic conditions. Data obtained show that the biodegradation of benzene and toluene occurs when Fe（ Ⅲ ） is used as the only electron acceptor. After incubating, the rate of biodegradation will obviously increase. The biodegradation experiment indicates that the biodegradation rate of toluene is faster than that of benzene. The half life of benzene and toluene are 4.02 and 3.81 days respectively.