Anaerobic biodegradability of alkylphenols and fuel oxygenates in the presence of alternative electron acceptors

Abstract

Alkylphenols and fuel oxygenates are important environmental pollutants produced by the petrochemical industry. A batch biodegradability test was conducted with selected ortho-substituted alkylphenols (2-cresol, 2,6-dimethylphenol and 2-ethylphenol), fuel oxygenates (methyl tert-butyl ether, ethyl tert-butyl ether and tert-amylmethyl ether) and tert-butyl alcohol (TBA) as model compounds. The ortho-substituted alkylphenols were not biodegraded after 100 days of incubation under methanogenic, sulfate-, or nitrate-reducing conditions. However, biodegradation of 2-cresol and 2-ethylphenol (150 mg l(-1)) was observed in the presence of Mn (IV) as electron acceptor. The biodegradation of these two compounds took place in less than 15 days and more than 90% removal was observed for both compounds. Mineralization was indicated since no UV-absorbing metabolites accumulated after 23 days of incubation. These alkylphenols were also slowly chemically oxidized by Mn (IV). No biodegradation of fuel oxygenates or TBA (1 g l(-1)) was observed after 80 or more days of incubation under methanogenic, Fe (III)-, or Mn (IV)-reducing conditions, suggesting that these compounds are recalcitrant under anaerobic conditions. The fuel oxygenates caused no toxicity towards acetoclastic methanogens activity in anaerobic granular sludge.

Anaerobic biodegradation of BTEX using Mn(IV) and Fe(III) as alternative electron acceptors

“…Petroleum fuels are crude distillates that comprise a complex mixture composed predominantly of paraffins, cycloparaffins and aromatic compounds, together with additives such as MTBE (Bowlen and Kosson, 1995;Puig-Grajales et al, 2000). The BTEX (benzene, toluene, ethylbenzene and xylene isomers) compounds are primary constituents of petroleum-distillate fuels, and are chemicals of environmental concern as they are relatively soluble, toxic, carcinogenic, and can be very mobile in the environment (Dean, 1985).…”

Benzene Biodegradation under Anaerobic Conditions Coupled with Metal Oxides Reduction

“…Basal phosphate (25 mM), buffered mineral medium (pH 7.0), vernadite (amorphous MnO 2 -oxide), and goethite (amorphous FeOOH-oxyhydroxide) were prepared as previously described (Puig-Grajales et al 2000). Sodium thioglycolate and ascorbic acid were added to the medium at a final concentration of 25 mg/L in order to eliminate traces of oxygen in the medium.…”

Limits of anaerobic biodegradation

“…Highly branched hydrocarbons such as pristane and phytane tend to be more slowly degraded compared to their linear counterparts in aerobic environments (Alexander, 1999). The gasoline oxygenates such as methyl-tert-butyl ether with quartenary carbons, which were introduced into the environment a decade ago, have proven to be quite difficult for anaerobic biodegradation due to the long residence time of these compounds in subsurface environments (Prince, 2000;Puig-Grajales et al, 2000). In the case of reductive dechlorination, hard to access chloro groups in polychlorinated biphenyls tend to be resistant to anaerobic biotransformations (Wiegel and Wu, 2000).…”