Environmental Engineering Reference
In-Depth Information
1.00E + 10
1.00E + 09
Pa 64 on verm
uninoculated soil
1.00E + 08
1.00E + 07
1.00E + 06
1.00E + 05
1.00E + 04
1.00E + 03
1.00E + 02
0
5
10
15
20
25
30
35
40
45
Time (days)
Figure 7.21 Survival of P. aeruginosa strain 64 on the vermiculite carrier in SMWT
site soil.
magnitude in the soil supplemented with the microbe vermiculite, suggest-
ing: (1) that addition of LB broth had a stimulating effect on the background
microbial population and (2) that these organisms were a major part of the
population. Their dominance lasted for at least 30 days. P. aeruginosa strain
64, which is a fluorescent pseudomonad, can be identified by the green
pigment released into the agar medium from the colonies. Pigment-produc-
ing colonies were observed up to about day 25, further suggesting that P.
aeruginosa strain 64 was present for considerable periods as a result of the
bioaugmentation on vermiculite. Strain EPA 505 or vermiculite was added
to SMWT soil, but was not detected during this experiment. In conclusion,
it appears that high concentrations of bacterial cells can be effectively intro-
duced into soil when carried on vermiculite. Inoculated vermiculite can be
prepared and stored in large quantities prior to use in a land-farming reme-
diation, a far simpler task than producing naked cells all at once just prior
to inoculation into the soil.
Figure 7.22 shows the ability of the added bacteria on vermiculite to
adapt to the POPILE soil during a 110-day microcosm incubation. Biostim-
ulation conditions (bulking agent (BA) and dried-blood fertilizer (DB)) pro-
duced an increase in viable bacterial colonies from the indigenous popula-
tions, but the greatest bacterial numbers were produced under
bioaugmentation conditions (Pa64), demonstrating the ability of the added
bacteria to survive in the highly contaminated soil.
 
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