BIOAUGMENTATION FOR THE IN SITU AEROBIC COMETABOLISM OF CHLORINATED SOLVENTS - Bioaugmentation for Groundwater Remediation - page 219

Table 8.1. Pilot Studies Performed at the Moffett Test Facility, California for Aerobic Cometabolism of CAHs Using Indigenous Microorganisms

Growth Substrates -
Average Injected
Concentration
(mg/L)

Injected
Concentration
(

Percent
Removal (%) Study CAH g/L) Key Findings

m

Semprini et al.
( 1990 )

Methane (5.3)
Oxygen (23.4)

TCE
trans-DCE
cis-DCE
VC

42-51
52-112
91-136
44

20-30
80-90
45-55
90-95

Cometabolism was concurrent with methane utilization

Less halogenated ethenes were transformed to a greater
extent

TCE removal was limited

1,1,1-TCA was not transformed

Semprini et al.
( 1991 )

Methane (6.6)
Oxygen (21.3)

TCE
trans-DCE
cis-DCE
VC

46
52
100
34

20
90
50
95

Results were consistent with previous tests

Methane inhibition of CAH transformation

Rates were temporally increased when a non-competing
substrate was added

Hopkins et al.
( 1993a )

Phenol (6.2-12.4)
DO (35)

TCE
cis-DCE

40
45

63-90
90

Microorganisms stimulated on phenol more effectively
transformed TCE and cis-DCE than those on methane

Greater removals were observed as phenol concentrations
were increased

Hopkins et al.
( 1993b )

Phenol (12.5-25)
DO (35)

TCE 62-1,000 88-90 Effective first-order removal was achieved over a broad

range of TCE concentrations

A maximum transformation yield of 0.062 g TCE/g phenol
was achieved

Hopkins and
McCarty
( 1995 )

Toluene (9)
Phenol (12.5)
DO (32)
H 2 O 2 (97)

TCE
trans-DCE
cis-DCE
1,1-DCE

250
125
125
65

50-90
74
90
50

Toluene was as effective as phenol in achieving TCE and
cis-DCE treatment

1,1-DCE transformation produced transformation toxicity
that lowered TCE removal efficiency

1,1,1-TCA as a background contaminant was not
transformed

Semprini et al.
( 2007b )

Butane (3.5-8.5)
DO (20)

1,1-DCE
1,1-DCA
1,1,1-TCA

65
200
140

86
0
0

1,1-DCE removal as observed

1,1,1-TCA and 1,1-DCA were not transformed

a TCA was present as a background contaminant at the Moffett Test Facility at a concentration of 46 m g/L. 1,1,1-TCA was not transformed to a significant extent in any of the tests
cited in Table 8.1
Note: m g/L-microgram(s) per liter; DO-dissolved oxygen; g-gram(s)