Environmental Engineering Reference
In-Depth Information
7.3.5.2.2 Surfactant production by added bacteria ( P. aeruginosa strain
64). When rhamnolipid is used in short-term extractions of phenanthrene
or fluoranthene from sand vs. sand with illite clay, desorption levels are
different. However, there was little difference in the amount desorbed from
the two substrates after 24 h. Rhamnolipid biosurfactant was much more
effective in extracting phenanthrene and fluoranthene than lichenysin bio-
surfactant. Therefore, P. aeruginosa strain 64 rhamnolipid biosurfactant was
selected for testing on PAH-contaminated soils.
To evaluate the potential of the P. aeruginosa strain 64 biosurfactant for
desorption of PAHs, a preliminary test was performed using three contam-
inated soils: Southern Maryland wood treatment (SMWT) site, POPILE wood
treatment site in Arkansas, and POPILE soil stored at the U.S. Army Water-
ways Experiment Station (WES) in Vicksburg, MS (Table 7.9). P. aeruginosa
strain 64 was grown in broth containing glycerol (an energy source that also
helps promote pyocyanin pigment production). After removing cells, the
supernatant at different concentrations was used to extract the PAH-contam-
inated soil.
7.3.5.3 Bioaugmentation
Past success of bioaugmentation at the field scale for enhanced bioremedi-
ation has been mixed, but there are examples of its effective use (Vogel, 1996).
Thibault et al. (1996) showed enhanced degradation of pyrene in soils
Table 7.9 Concentrations of PAHs in Soils Used to Evaluate the Effectiveness of
Biosurfactant for Desorption
Concentration (mg/g)
Southern
Maryland Wood
Treatment Site a
Popile Wood
Treatment Site
(Arkansas)
Land
Treatment
Units (LTUs)
PAH Homologue
Naphthalene
0.5
2273
92
Acenaphthalene
7
19
11
Fluorene
14
1073
803
Anthracene
3
2080
1308
Phenanthrene
39
3810
2756
Fluoranthene
21
1880
1600
Pyrene
15
1237
991
Benzo(a)anthracene
3
291
225
Chrysene
3
324
261
Benzo(b)fluoranthene
1
101
97
Benzo(f)fluoranthene
1
96
85
Benzo(a)pyrene
1
76
65
Indenopyrene
<0.5
29
24
Total PAHs
236
1519
9150
PCP
280
2307
2340
a GC-MS analysis done by Dr. Sabine Apitz and Kathy Meyers-Schulte at SPAWARSY-
SCEN in San Diego, CA.
 
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