Comparison of biostimulation versus bioaugmentation with bacterial strain PM1 for treatment of groundwater contaminated with methyl tertiary butyl ether (MTBE).
Widespread contamination of groundwater by methyl tertiary butyl ether (MTBE) has triggered the exploration of different technologies for in situ removal of the pollutant, including biostimulation of naturally occurring microbial communities or bioaugmentation with specific microbial strains known to biodegrade the oxygenate. After laboratory studies revealed that bacterial strain PM1 rapidly and completely biodegraded MTBE in groundwater sediments, the organism was tested in an in situ field study at Port Hueneme Naval Construction Battalion Center in Oxnard, California. Two pilot test plots (A and B) in groundwater located down-gradient from an MTBE source were intermittently sparged with pure oxygen. Plot B was also inoculated with strain PM1. MTBE concentrations up-gradient from plots A and B initially varied temporally from 1.5 to 6 mg MTBE/L. Six months after treatment began, MTBE concentrations in monitoring wells down-gradient from the injection bed decreased substantially in the shallow zone of the groundwater in plots A and B, thus even in the absence of the inoculated strain PM1. In the deeper zone, downstream MTBE concentrations also decreased in plot A and to a lesser extent in plot B. Difficulties in delivery of oxygen to the deeper zone of plot B, evidenced by low dissolved oxygen concentrations, were likely responsible for low rates of MTBE removal at that location. We measured the survival and movement of strain PM1 in groundwater samples using two methods for detection of DNA sequences specific to strain PM1: TaqMan quantitative polymerase chain reaction, and internal transcribed spacer region analysis. A naturally occurring bacterial strain with > 99% 16S rDNA sequence similarity to strain PM1 was detected in groundwater collected at various locations at Port Hueneme, including outside the plots where the organism was inoculated. Addition of oxygen to naturally occurring microbial populations was sufficient to stimulate MTBE removal at this site. In some cases, however, inoculation with an MTBE-degrading culture may be warranted.
Smith
Amanda E
AE
Department of Land, Air and Water Resources, University of California, Davis, California, USA.
Hristova
Krassimira
K
Wood
Isaac
I
Mackay
Doug M
DM
Lory
Ernie
E
Lorenzana
Dale
D
Scow
Kate M
KM
D001420:Bacteria, Aerobic / Q000235:genetics / Q000502:physiology*; D001673:Biodegradation, Environmental; D002273:Carcinogens / Q000378:metabolism*; D004269:DNA, Bacterial / Q000032:analysis; D004784:Environmental Monitoring; D008738:Methyl Ethers / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D012989:Soil Pollutants / Q000378:metabolism*; D012997:Solvents; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D002273:Carcinogens; D004269:DNA, Bacterial; D008738:Methyl Ethers; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D012997:Solvents; D014874:Water Pollutants, Chemical; C043243:methyl tert-butyl ether
Appl Environ Microbiol. 1999 Nov;65(11):4788-92
10543787
Appl Environ Microbiol. 2001 Apr;67(4):1975-8
11282660
Environ Microbiol. 2001 Mar;3(3):220-5
11321538
Environ Sci Technol. 2001 Jan 15;35(2):312-7
11347603
Environ Sci Technol. 2001 Mar 15;35(6):1118-26
11347923
Appl Environ Microbiol. 2003 May;69(5):2616-23
12732529
Environ Sci Technol. 2001 May 1;35(9):1785-90
11355193
Biodegradation. 2000;11(2-3):171-86
11440243
Appl Environ Microbiol. 2001 Nov;67(11):5154-60
11679339
Appl Environ Microbiol. 2001 Dec;67(12):5824-9
11722940
Environ Sci Technol. 2002 Jan 15;36(2):190-9
11827053
Environ Sci Technol. 2001 Feb 15;35(4):658-62
11349274