Premium
Oxygen‐Enhanced Biodegradation of Phenoxy Acids in Ground Water at Contaminated Sites
Author(s) -
Tuxen Nina,
Reitzel Lotte A.,
Albrechtsen HansJørgen,
Bjerg Poul L.
Publication year - 2005
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.2005.00104.x
Subject(s) - biodegradation , contamination , oxygen , environmental chemistry , chemistry , environmental science , ecology , organic chemistry , biology
The effects of adding oxygen to anaerobic aquifer materials on biodegradation of phenoxy acid herbicides were studied by laboratory experiments with aquifer material from two contaminated sites (a former agricultural machinery service and an old landfill). At both sites, the primary pollutants were phenoxy acids and related chlorophenols. It was found that addition of oxygen enhanced degradation of the six original phenoxy acids and six original chlorophenols. Inverse modeling on 14 C 4‐chloro‐2‐methylphenoxypropanoic acid (MCPP) degradation curves revealed that increasing the oxygen concentrations from <0.3 mg/L up to 7 to 8 mg/L shortened the lag phases (from ∼150 d to 5 to 25 d) and increased first‐order degradation rate constants by 1 order of magnitude (from ∼5 × 10 −2 d −1 to up to 30 × 10 −2 d −1 ). Additionally, the degree of MCPP mineralization was increased (30% to 50% mineralized at low oxygen concentrations and 50% to 70% mineralized at high oxygen concentrations, based on 14 CO 2 recovery). These positive effects on degradation were observed even at relatively low oxygen concentrations (2 mg/L). Furthermore, effects related to the addition of oxygen on the general geochemistry were studied. An oxygen consumption of 2.2 to 2.6 mg O 2 /g dw was observed due to oxidation of solid organic matter and, to some extent (0.5% to 11% of the total oxygen consumption), water‐soluble compounds such as Fe 2+ , dissolved Mn, nonvolatile organic carbon, and NH 4 + . Overall, the results suggest that stimulated biodegradation by addition of oxygen might be a feasible remediation technology at herbicide‐contaminated sites, although oxygen consumption by the sediment could limit the applicability.