Anaerobic Degradation of Methyl tert-Butyl Ether (MTBE) and tert-Butyl Alcohol (TBA)

Abstract

The potential for anaerobic degradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) was investigated in laboratory incubations of sediments from a petroleum-contaminated aquifer and in aquatic sediments. The addition of humic substances (HS) stimulated the anaerobic degradation of MTBE in aquifer sediments in which Fe(III) was available as an electron acceptor. This is attributed to the fact that HS and other extracellular quinones can stimulate the activity of Fe(III)-reducing microorganisms by acting as an electron shuttle between Fe(III)-reducing microorganisms and insoluble Fe(III) oxides. MTBE was not degraded in aquifer sediments without Fe(III) and HS. [14C]-MTBE added to aquatic sediments adapted for anaerobic MTBE degradation was converted to 14CO2 in the presence or absence of HS or the HS analog, anthraquione-2,6-disulfonate. Unamended aquatic sediments produced 14CH4 as well as 14CO2 from [14C]-MTBE. The aquatic sediments also rapidly consumed TBA under anaerobic conditions and converted [14C]-TBA to 14CH4 and 14CO2. An adaptation period of ca. 250-300 days was required prior to the most rapid anaerobic MTBE degradation in both sediment types, whereas TBA was metabolized in the aquatic sediments without a lag. These results demonstrate that, under the appropriate conditions, MTBE and TBA can be degraded in the absence of oxygen. This suggests that it may be possible to design strategies for the anaerobic remediation of MTBE in petroleum-contaminated subsurface environments.

Biodegradation of three selected benzotriazoles under aerobic and anaerobic conditions

“…Inhibition of dehalogenation of monoaromatics in the presence of sulfate was also well documented in the literature (Gibson and Suflita, 1986;Madsen and Aamand, 1991;Milligan and Haggblom, 1999). Significant faster biodegradation of 5-TTri and CBT under Fe (III) reducing conditions in the present study suggests that Fe (III) reducing condition as a common anaerobic terminal electron accepting process in aquifer systems (Finneran and Lovley, 2001;Bradley et al, 2002) are favorable for the degradation of 5-TTri and CBT, but not for BT in aquifer environment. This can explain higher persistence of BT than 5-TTri and CBT reported in some aquifer systems (Cancilla et al, 2003).…”

Biodegradation of three selected benzotriazoles in aquifer materials under aerobic and anaerobic conditions

“…Inhibition of dehalogenation of monoaromatics in the presence of sulfate was also well documented in the literature (Gibson and Suflita, 1986;Madsen and Aamand, 1991;Milligan and Haggblom, 1999). Significant faster biodegradation rates of BT, 5-TTri and CBT under Fe (III) reducing condition in the present study suggest that Fe (III) reducing condition, as a common anaerobic condition in aquifer systems (Bradley et al, 2002;Finneran and Lovley, 2001), is favorable for the biodegradation of these BTs.…”

Biodegradation of the ultraviolet filter benzophenone‐3 under different redox conditions

“…Biodegradation of BP-3 was also observed under Fe (III)-reducing conditions. Iron (III) reduction is a common anaerobic terminal electron-accepting process in anaerobic systems of the natural environment [30,31]. This suggests that BP-3 in the natural environment would be less persistent under Fe (III)-reducing condition than under oxic conditions.…”