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Domtar Wood Preserving
Site
Trenton, Ontario, Canada
Project
Bioremediation of Polycyclic Aromatic
Hydrocarbon (PAH) & Pentachlorophenol
Summary
Soils impacted with PAH and Pentachlorophenol
were treated in situ and ex situ in an
independent study for the US EPA Superfund
Innovative Technology Evaluation (SITE)
program. The in situ treatment
plot’s initial mean PAH concentration was
118.0 mg/kg. Chlorophenol was not evaluated in
the in situ plot due to a very low
initial mean concentration of 1.61 mg/kg. The
ex situ treatment plot’s initial
mean PAH concentration was 1,774.4 mg/kg, and
the chlorophenol initial mean concentration was
182.8 mg/kg. The PAH mean concentrations were
reduced by 95%. The chlorophenol mean
concentration was reduced by 98%.
The Challenge
Remedial goals for PAHs and chlorophenols were
established by the Canadian Council of
Ministers of the Environment (CCME) in 1991
(Table 1). To reach these criteria, (e.g., PCP
= 5 mg/kg, Benzo(a)pyrene = 10 mg/kg, etc.)
removal efficiencies as high as 99% were
required in some sampling zones for some
compounds.
Table 1. DARAMEND Bioremediation on PAHs at a
former wood preserving
facility.
| |
Concentration (mg/kg)
|
| |
Ex Situ
(batch 1)
|
Ex Situ
(batch 2)
|
Guideline
|
| PAH Isomer |
Initial
|
251 days
|
Initial
|
209 days
|
(CCME)1
|
| Naphthalene |
3
|
2
|
2
|
1
|
40
|
| Acenaphthylene |
3
|
1
|
4
|
(0.2)2
|
--
|
| Acenaphthene |
9
|
1
|
28
|
0.2
|
--
|
| Flourene |
3
|
1
|
23
|
(0.2)
|
--
|
| Phenanthrene |
15
|
7
|
104
|
0.4
|
40
|
| Anthracene |
20
|
6
|
35
|
(0.2)
|
--
|
| Fluoranthene |
206
|
12
|
428
|
2
|
40
|
| Pyrene |
153
|
10
|
370
|
4
|
40
|
| Benzo(a)anthracene |
35
|
5
|
60
|
2
|
40
|
| Chrysene |
58
|
5
|
162
|
1
|
--
|
| Benzo(b+K)fluoranthene |
60
|
12
|
140
|
13
|
--
|
| Benzo(a)pyrene |
22
|
6
|
33
|
4
|
10
|
| Indeno(1,2,3-c,d)pyrene |
14
|
5
|
21
|
4
|
--
|
| Dibenzo(a,h)anthracene |
13
|
1
|
14
|
(0.2)
|
9
|
| Benzo(g,h,i)perylene |
12
|
5
|
20
|
4
|
40
|
| Total PAHs |
619
|
79
|
1,442
|
36
|
--
|
1. Canadian Council of Ministers of the
Environment Interim Soil Quality Criteria
(1991).
2. Values in parenthesis indicate the method
detection limit for samples reported as less
than the method detection limit.
The Solution
DARAMEND® was applied ex situ in two
treatment cells (plots) and in situ in
one treatment plot. The treatment cells were
enclosed within a greenhouse enclosure to
extend the length of the effective treatment
season. DARAMEND® was applied to the soil
surface and incorporated to a depth of 2 ft.
with a specialized deep rotary tiller. Mixing
also aerated and homogenized the soil. Water
was then applied to increase and maintain the
soil moisture content to 50%-60% of the soil
water holding capacity.
The Result
DARAMEND® bioremediation technology
supported efficient removal of all target
compounds in soil at the Domtar Wood Preserving
Site to levels below the CCME criteria. This
project was evaluated by the US EPA under its
SITE program and was determined to be among the
most effective bioremediation technologies
available for use on soils impacted with wood
preserving chemicals.
• PAH concentrations within the ex
situ plot were reduced by 95% (1,774.4
mg/kg to 95.2 mg/kg).
• Chlorophenol concentrations within the
ex situ plot were reduced by 98%
(182.8 mg/kg to 3.3 mg/kg).
• PAH levels within the in situ
plot were reduced by 47% (118.0 mg/kg to 62.6
mg/kg).
The Cost
The costs, as estimated by the US EPA during
the SITE program evaluation, were approximately
$60/ton for in situ applications and
less than $90/ton for ex situ
applications.
The Timeline
Treatment required 209 days in one treatment
cell, 259 days in the other, and 308 days
in situ.
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