United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA 510-F-93-029
October 7993
4>EPA An Overview of
Underground Storage Tank
Remediation Options
-------
-------
EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
October 1993
An Overview Of
Underground Storage Tank
Remediation Options
Contents
,Groundwatef Remediation . , ;
"= -^
In Situ Air Sparging With Soil Vapor Extraction
EPA510-F-93-017
In Situ Bioremediatioii
EPA 510-F-93-018
In Situ Bioventing Combined With Low
Flow Air Sparging (Biosparging)
EPA 510-F-93-019
Vacuum Enhanced Pump and Treat
EPA 510-F-93-020
Pump and Treat
EPA 510-F-93-030
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-------
xvEPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-017
October 1993
Groundwater
Remediation For
UST Sites
In Situ Air Sparging With
Soil Vapor Extraction
In situ air sparging with soil vapor extraction (SVE) is
a technique for removing dissolved volatile contaminants
from groundwater. The technique injects air into the
saturated zone. The air forms bubbles that rise into the
unsaturated zone, carrying trapped and dissolved
contaminants. Extraction wells in the unsaturated zone
capture sparged air. If necessary, the air can then be
treated using a variety of vapor treatment options.
This technique is most effective in homogenous, permeable
aquifers. Performance data for this technique are limited.
In situ air sparging with soil vapor extraction is a rapid
remediation technique that can reduce contamination
levels in six months. It is also able to quickly remove
volatile organic compounds (VOCs) from below the
groundwater table.
Petroleum Types And Constituents
Gasoline and diesel ~ , . /
« Volatile organic compounds (VOCs) such as
benzene, toluene, ethylbenzene, and xylene (BTEX)
-------
la Situ Air Sparging With Soil Vapor Extraction
Advantages
Limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Tuning2
Costs5
Rapidly reduces volatile organic compounds (VOCs) from
below groundwater table
Can enhance and accelerate effectiveness of soil vapor
extraction (SVE) and downgradient pumping
Removes primarily volatile constituents
Effectiveness is limited in low permeability or
heterogeneous media
Difficult to control air distribution in groundwater
Can promote vapor and plume migration
Limited performance data are available; contaminant
levels may rebound over time
Vertical or horizontal extraction and injection wells
Trenches
Vacuum pump, compressor, or blower
Aboveground vapor treatment equipment (optional)
Vapor treatment options (if needed):
Vapor phase biofilter
Granulated activated carbon
Internal combustion engine
Catalytic oxidation unit
Thermal incinerator
Vacuum/pressure monitoring at the wellhead, pump,
compressor, blower, and observation points
Airflow rate
Vapor concentrations
Dissolved oxygen
Water levels
Constituent concentrations in groundwater and soil
Generally achieves maximum contaminant levels (MCLs)
for volatile constituents
For an ideal site3, ~90% reduction in 6 months to 1 year
For an average site4, ~90% reduction in 6 months to 2
years
For an ideal site3, $60,000 to $180,000
For an average site4, $120,000 to $200,000
^Parameters to monitor" are for performance purposes only; compliance monitoring parameters vary by state.
2Cteanup standards are determined by the state.
3An "ideal site" assumes no delays in corrective action and a relatively homogenous, permeable subsurface.
^An "average site" assumes minimal delays in corrective action and a moderately heterogeneous and permeable subsurface.
^Costs include equqxnent, and operation and maintenance.
-------
IvyEPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-018
October 1993
Groundwater
Remediation For
UST Sites
In Situ Bioremediation
In situ bioremediation is a technique for removing
biodegradable contaminants from groundwater. The
technique relies on microorganisms and supplemental
oxygen and nutrients to break down petroleum products
in the groundwater.
In situ bioremediation offers the advantage of being able
to treat contamination in place, without the need for
pumping or the subsequent treatment of pumped
groundwater. The technique is most effective in
permeable aquifers.
Petroleum Types And Constituents
Fresh or weathered gasoline, diesel, jet fuel,
kerosene, motor oil, heavy fuel oil, lubricating oils,
and crude oils ~
Volatile organic compounds (VOCs) such as
benzene, toluene, ethylbenzene, and xylene (BTEX);
residual semivolatile organic compounds (SVOCs)
such as polynuclear aromatic hydrocarbons; and
nonvolatile constituents ,~ ,-° ,-> .
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In Situ Bioremediation
Advantages
Limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs5
Degrades contaminants in place
Achieves lower concentration levels than pump and
treat
Effectiveness is limited in low permeability or
heterogeneous media
Ability to transport nutrients and oxygen might be
limited by soil and groundwater mineral content or pH
Targets only biodegradable constituents
Groundwater containment system
Oxygen delivery equipment
Nutrient delivery equipment
Injection trenches
Recovery walls or trenches
Pumps
Monitoring points
Recirculated groundwater treatment options:
Air stripping
Granulated activated carbon
Bioreactors
Constituent concentrations in groundwater
Mcrobial population in aquifer
pH and total organic carbon
Dissolved oxygen
Nutrient concentration
How rates
Generally, can achieve maximum contaminant levels
(MCLs)
Achieves > 90% reduction of biodegradable constituents
For an ideal site3, ~90% in 6 months to 1 year
For an average site4, ~90% in 6 months to 4 years
Longer time required to degrade heavier hydrocarbons
For an ideal site3, $150,000 to $250,000
For an average site4, $200,000 to $500,000
'"Parameters to mentor" are for performance purposes only; compliance monitoring parameters vary by state.
Cleanup standards are determined by the state.
3An "ideal site* assumes no delays in corrective action and a relatively homogeneous, permeable subsurface.
4An Average site" assumes mhhial delays h corrective action and a moderately heterogeneous and permeable surface.
5Costs Include equipment, and operation and maintenance.
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&EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403V/
EPA510-F-93-019
October 1993
Groundwater
Remediation For
UST Sites
In Situ Bioventing
Combined With Low
Flow Air Sparging
(Biosparging)
In situ bioventing combined with low flow air sparging
(biosparging) stimulates the aerobic biodegradation of
organic contaminants in groundwater by delivering
oxygen to the saturated and unsaturated zones. The oxygen
is delivered at a slow rate to encourage biodegradation
rather than volatilization.
Biosparging degrades volatile organic compounds (VOCs)
in place, reducing the need for subsequent vapor
treatment and the costs of remediation. This technique
is most effective in permeable aquifers.
Petr olejum Types Anid Constituents^
Fresh or weathered gasoline, diesel, jet fuel,
kerosene, motor oil, fuel oil, lubricating oils,
and crude oils , - x " :
Volatile organic compounds (VOCs) such as
benzene, toluene, ethylbenzene, and xylene (BTEX);
and residual semivolatile organic compounds
(SVOCs) such as polynuclear aromatic
hydrocarbons - - -
-------
In Situ Bioventing Combined With Low Flow Air Sparging
(Biosparging)
Advantages
limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs3
Degrades volatile organic compounds (VOCs) in place
Reduces air emissions and subsequent need for vapor
treatment
Effectiveness is limited in low permeability or
heterogeneous media
Difficult to control air distribution in groundwater
« limited performance data available
Vertical or horizontal extraction and injection wells
Vacuum pump, compressor, or blower
Aboveground vapor treatment (optional)
Vapor treatment options (might be needed for high
concentrations of contaminants):
« Vapor phase bio filters
Granulated activated carbon
, Internal combustion engine
Catalytic oxidation unit
Thermal incinerator
Vacuum/pressure monitoring at the pump, compressor,
blower, and observation points
Airflow rate
Dissolved oxygen
Water levels
Constituent concentrations in groundwater
Generally achieves maximum contaminant levels (MCLs)
for volatile constituents
New application; to date, few sites have been fully
remediated
Estimates for an ideal site4, $60,000 to $180,000
Estimates for an average site5, $120,000 to $200,000
Costs vary depending on vapor treatment costs and
treatment time
""Parameters to monitor are for performance purposes only; compliance monitoring parameters vary by state.
^cleanup standards are determined by the state.
%osts Include equipment, and operation and maintenance.
4An Ideal sis" assumes no delays h correctivB action and a relatively homogenous, peimeable subsurface.
5An "average site* assumes m Wrnal delays in corrective action and a moderately heterogeneous and permeable subsurface.
-------
&EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-020
October 1993
Ground water
Remediation For
UST Sites
Vacuum Enhanced
Pump And Treat
Vacuum enhanced pump and treat is a technique that
uses a surface-mounted vacuum pump to remove
contaminated soil vapors and groundwater simultaneously.
This method increases the rate of pumping, reducing
remediation time. The pumped water and soil vapors
can then be treated with a number of techniques.
Vacuum enhanced pump and treat is most effective when
used in aquifers with medium to low permeability (silts
and clays).
This method offers pumping rates that are 3 to 10 times
greater than conventional pump and treat rates.
Increased pumping rates result in decreased remediation
time.
Petroleum Types And Constituents
Dissolved gasoline and diesel, jet fuel, and
kerosene
Dissolved constituents such as benzene, toluene,
ethylbenzene, and xylene (BTEX)
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Vacuum Enhanced Pump And Treat
Advantages
Limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs5
Controls contaminant plume migration and reduces plurne
concentrations
Increases recovery rate of pumping by 3 to 10 times, reducing
remediation time
Effective in aquifers with low permeability
Can remove residuals from dewatered aquifer soils
Can require treatment of vapors from vacuum pump
Generates larger volume of water for treatment in a shorter
time than conventional pump and treat
Requires control of water table fluctuation to minimize
smearing contaminants
High iron content/hardness can affect water treatment
Vertical or horizontal extraction wells
Trenches
Vacuum blower or pump
Water pumps
Aboveground air/water treatment systems
Vapor treatment options:
Vapor phase biofilter
Granulated activated carbon
Internal combustion engine
Catalytic oxidation unit
Thermal incinerator
Water treatment options:
Air stripping
Granulated activated carbon
Bioreactors
Vacuum/pressure monitoring at well head, pump, blower
Airflow rate
Water discharge rate
Water levels
Constituent concentrations in groundwater
Influent and effluent concentrations from water treatment
system
Might not achieve maximum contaminant levels (MCLs)
For an ideal site3, 6 months to 1 year
For an average site4, 6 months to 2 years
For an ideal site3, $80,000 to $120,000
For an average site4, $100,000 to $180,000
Higher initial costs than some alternatives, but shorter
remediation time might lower total cost
'Parameters to monitor" are for performance purposes only; compliance monitoring parameters vary by state.
Cleanup standards are determined by the state.
3An Idea! site' assumes no delays in corrective action and a relatively homogenous, permeable subsurface.
4An "average site* assumes minimal delays in corrective actfon and a moderately heterogeneous and permeable subsurface.
^Costs Includa equipment, and operation and maintenance.
-------
&EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-030
October 1993
Ground water
Remediation F
UST Sites
Pump And Treat
Pump and treat is a technique that brings contaminated
groundwater above the ground through the use of
extraction wells. The water is then treated, normally
using one of three processes: granulated activated
carbon, air stripping, or bioremediation.
This technique is most effective in permeable aquifers. It
also can be used with in situ vapor extraction (SVE) to
enhance removal of volatile contaminants from the zone
of water table fluctuation.
A limitation of pump and treat is that it can take a long
time to achieve complete remediation, sometimes as long
as seven years even for an ideal site. In addition, this
method is subject to fluctuations of the water table that
can smear contaminants and complicate cleanups.
Petroleum Types And Constituents
Dissolved gasoline and diesel, jet fuel, and
kerosene
Dissolved constituents such as benzene, toluene,
ethylbenzene, and xylene (BTEX)
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Pump And Treat
Advantages
Limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs5
Controls contaminant plume migration and reduces
plume concentration
Not very effective in aquifers with low permeability
Can require expensive and lengthy long-term pumping
and treating
High iron content/hardness can affect water treatment
Requires control of water table fluctuation to miniroize
smearing contaminants
Might require off-site discharge permits
Vertical or horizontal extraction wells
Trenches
Water pumps
Aboveground water handling and/or treatment systems
Wastestream treatment options:
Air stripping
Granulated activated carbon
Bioreactors
Constituent concentrations in groundwater
Influent and effluent concentrations from water
treatment system
Water discharge rate
Water levels
Might not meet cleanup standards or maximum
contaminant levels (MCLs)
For an ideal site3, 3 to 7 years
For an average site4, 3 to 10 years or longer
For anideal site3, $150,000 to $200,000
For an average site4, $250,000 to $300,000
''Parameters to monitor* are for performance purposes only; compliance monitoring parameters vary by state.
Cleanup standards are determined by the state.
3An "ideal site" assumes no delays in corrective action and a relatively homogenous, permeable subsurface.
*An "average site* assumes m'rimal delays in corrective action and a moderately heterogeneous and permeable subsurface.
'Costs include equipment, and operation and maintenance.
-------
k>EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
October 1993
An Overview Of
Underground Storage Tank
Remediation Options
Contents
Soil Remediation , ;
In Situ Soil Vapor Extraction
EPA510-F-93-021
In Situ BioremediationBioventing
EPA510-F-93-022
Ex Situ BioremediationBiomounding
EPA 510-F-93-023
On-Site Low Temperature Thermal Desorption
EPA510-F-93-024
Ex Situ BioremediationLand Farming
EPA 510-F-93-025
In Situ Passive Biodegradation
(Natural Attenuation)
EPA510-F-93-026
Excavation and Off-Site Treatment
EPA 510-F-93-027
Excavation With Off-Site Landfill Disposal
EPA 510-F-93-028
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-------
&EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-021
October 1993
Soil Remediation For
UST Sites
In Situ Soil Vapor
Extraction
In situ soil vapor extraction (SVE) is a technique for
removing contaminants from unsaturated soils. The
technique draws fresh air into the ground with a vacuum
pump. The air brings the contaminants to the surface,
where they can be treated and safely discharged.
In situ soil vapor extraction is most effective in
coarse-grained soils such as sand and gravel. It requires a
minimum 5-foot-thick unsaturated zone of soil. This
technique can be used in conjunction with air sparging,
groundwater pumping, or bioremediation systems.
This technique is able to treat large volumes of soil
effectively and with minimal disruption to business
operations. It also can remove contamination from near
or under fixed structures.
Petroleum Types And Constituents
* Fresh and weathered gasoline and diesel
Volatile organic compounds (VOCs) such as
benzene, toluene, ethylbenzene, andxylene
(BTEX); and semivolatile organic compounds
(SVOCs) /
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In Situ Soil Vapor Extraction
Advantages
Limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs5
Effectively treats large volumes (>1,000 cu yd) of soil
Removes contamination near or under fixed structures
Causes minimal disruption to business operations
Removes volatile contaminants from the zone of water
table fluctuation '
Effectiveness limited in heterogeneous soils or soils with
high clay or organic content
Airflow may not contact all parts of soil
Leaves residual constituents in soil
Might require air discharge permits
Vertical or horizontal extraction wells
Trenches
Vacuum blower or pump
Injection and passive inlet wells
Aboveground vapor treatment equipment (optional)
Vapor treatment options (if needed):
Vapor phase biofllter
Granulated activated carbon
Internal combustion engine
Catalytic oxidation unit
Thermal incinerator
Vapor concentration
Airflow rate
Can remove 90% of volatile organic compounds (VOCs)
and semivolatile organic compounds (SVOCs)
For an ideal site3, 90% in 6 months to 1 year
For an average site4, 90% in 6 months to 3 years
Longer time required for heterogeneous soils and less
volatile constituents
For an ideal site3, $40,000 to $120,000
For an average site4, $100,000 to $150,000
Vapor treatment costs can drastically affect total costs
'Taramelers to monitor* are for performance purposes only; compliance monitoring parameters vary by state.
Cleanup standards are determined by the state.
3An Ideal site" assumes no delays in corrective action and a relatively homogeneous, permeable subsurface.
*An laverage sle" assumes m Wmal delays in corrective action and a moderately heterogeneous and permeable subsurface.
5Costs include equipment, and operation and maintenance.
-------
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-022
October 1993
v°/EPA
Soil Remediation For
UST Sites
In Situ Bioremediation:
Bioventing
In situ bioremediationbioventingis a technique for
removing biodegradable contaminants from
unsaturated soils. The technique injects oxygen into
contaminated soil The oxygen stimulates the aerobic
biodegradation of the organic contaminants in the soil
Oxygen is delivered at a low rate to encourage
biodegradation rather than volatilization.
Bioventing is most effective in coarse-grained soils such as
sand and gravel. It requires a minimum 5-foot-thick
unsaturated zone. This technique can be used in
conjunction with air sparging or groundwater pumping
systems.
This technique is able to treat large volumes of soil
effectively and with minimal disruption to business
operations. It also can remove contamination from near
or under fixed structures. Bioventing also reduces the
need for aboveground treatment because it works to
degrade contaminants in place.
Petroleum Types And Constituents ;
Fresh or weathered gasoline,' diesel, jet fuel,^
kerosene, motor oil, heavy fuel oil, lubricating oils,
and crude oils
Volatile organic compounds (VOCs) such as
benzene, toluene, ethylbenzene, andxylene (BTEX);
residual semivolatile organic compounds (SVOCs),
such as polynuclear aromatic hydrocarbons;^ and
nonvolatile constituents . / - "" ' ,
-------
In Situ Bioremediation: Bioventing
" ' ' " ' ^"^" . .,.', .'... .' . . i i ,'.,,:,-'"' . -..'
Advantages
limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs5
Degrades semivolatile organic compounds (SVOCs) and
nonvolatile organic compounds
Effectively treats large volumes (>1,000 cu yd) of soil
Causes minimal disruption to business operations
Degrades contaminants near or under fixed structures
Degrades volatile organic compounds (VOCs) in place, which
reduces air emissions and subsequent need for treatment
Targets only biodegradable constituents
Is a relatively slow process
Requires sufficient nutrients, moisture, active indigenous
microbial population, and pH of 6-9 to degrade contaminants
Effectiveness limited in heterogeneous soils
Vertical or horizontal extraction wells
Trenches
Vacuum blower or pump
Injection and passive inlet wells
Vapor treatment (optional)
Nutrient delivery equipment (optional)
Vapor treatment options (might be needed for high
concentrations of contaminants):
Vapor phase biofllter
Granulated activated carbon
Internal combustion engine
Catalytic oxidation unit
Thermal incinerator
Vapor concentration
Airflow rate
In situ respiration rate (oxygen consumption and carbon dioxide
production)
Soil contaminant concentration
Microbial population
Soil pH, moisture, and nutrients
Treats > 90% of biodegradable constituents
For an ideal site3, ~90% in 1 to 2 years
For an average site4, ~90% in 1 to 4 years
Longer time required to degrade heavier hydrocarbons
For an ideal site3, $40,000 to $120,000
For an average site4, $100,000 to $150,000
Vapor treatment and longer treatment times increase costs
''Parameters to monitor* are for performance purposes only; compliance monitoring parameters vary by state.
^Cleanup standards are determined by the state.
3An Ideal site" assumes no delays In corrective action and a relatively homogenous, permeable subsurface.
4An "average sla" assumes minimal delays in cxxrective action and a moderately heterogeneous and permeable subsurface.
^Costs include equipment, and operation and maintenance.
-------
IvvEPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-023
October 1993
Soil Remediation For
UST Sites
Ex Situ Bioremediation:
Biomounding
Ex situ bioremediationMomoundingis a technique
for removing biodegradable contaminants from
excavated mounds of soil. Nutrients are added to the soil
mounds, which are often several feet high, to facilitate
bioremediation. Aeration conduits and irrigation systems
are constructed in the mound.
Biomounding is most appropriate for shallow
contamination sites that cover a large horizontal area.
This is a low-maintenance technique that requires a
relatively short treatment time. Biomounding also
provides better control over aeration, moisture,
nutrient levels, and soil texture than other methods.
Petroleum Types And Constituents
f < >
Fresh, or weathered gasoline, diesel, jet fuel,
kerosene, motor oil, heavy fuel oil, lubricating oils,
and crude oils
i- '
Volatile organic compounds (VOCs) such as
benzene, toluene, ethylbenzene, and xylene.(BTEX);
residual semivolatile organic compounds (SVOCs)
such as polynuclear aromatic hydrocarbons; and ^
nonvolatile constituents ' ,
-------
Ex Situ Bioremediation: Biomounding
Advantages
Degrades semivolatile organic compounds (SVOCs) and
nonvolatile organic compounds
Requires low maintenance
Entails a relatively short treatment time
Enhances control and management of aeration, moisture,
nutrients, and soil texture
Can use treated soil as backfill
limitations
Targets only biodegradable constituents
Must excavate soil and remove debris
Requires sufficient nutrients, moisture, active indigenous
microbial population, and pH of 6-9 to degrade contaminants
System
Components
Plastic liner
Gravel and slotted pipe to provide air to mound
Nutrients
Blower
Soil vapor sampling probes
Irrigation system (optional)
Plastic cover (optional)
Vapor treatment equipment (optional)
Wastestream
Treatment
Vapor treatment options (might be needed for high
concentrations of contaminants):
Granulated activated carbon
Internal combustion engine
Catalytic oxidation unit
Thermal incinerator
Parameters to
Monitor1
Vapor concentration
Airflow rate
Soil contaminant concentration
Microbial population
Soil pH, moisture, and nutrients
Leachate analysis (optional)
Cleanup Levels
and Timing2
Treats > 90% of biodegradable constituents
For an ideal site3, -90% in 6 months to 18 months
For an average site4, ~90% in 6 months to 2 years
Longer time required to degrade heavier hydrocarbons
Costs5
For an average site4, $80,000 to $125,000 ($80 to $125/cu yd)
Unit costs generally decrease as soil volume increases
''Parameters to monitor" are for performance purposes only; compliance monitoring parameters vary by state.
^Cleanup standards are determined by the state.
An "ideal site* assumes no delays h corrective action and a relatively homogeneous, permeable subsurface.
An "^average sle* assumes mWmal delays n corrective action and a moderately heterogeneous and permeable subsurface.
TJosts include equipment, and operation and maintenance.
-------
&EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-024
October 1993
Soil Remediation For
UST Sites
On-Site Low
Temperature Thermal
Desorption
Low temperature thermal desorption is a technique
for removing contaminants from large volumes
(greater than 1,000 cubic yards) of soil. The technique
heats contaminated soil to relatively low temperatures
(200-1,000°F). The heat causes contaminants to vaporize
so that they can be treated with air emissions treatment
systems.
On-site thermal treatment is most effective on soil that
contains high levels of hydrocarbons. It requires less time
than bioremediation or soil vapor extraction (SVE). On-site
thermal treatment can be implemented rapidly and works
quicklywithin six to eight weeksat a relatively low cost.
Petroleum Types And Constituents
All types of petroleum products
-------
On-Site Low Temperature Thermal Desorption
Advantages
Limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs3
Rapid to implement
Minimizes long-term liability
Can reuse some types of soil for backfill
Expensive for soil with high moisture or day content
Might require air discharge permits
Excavation equipment
Sorting and sizing equipment
Rotary kiln
Offgas treatment equipment
Air emissions equipment
Contaminant concentrations in pre- and post-treatment
soil
Can excavate to cleanup standards
>99% removal efficiency
Typically completed in 6 to 8 weeks
For an average site4, $60,000 to $100,000 ($60 to
$100/cu yd)
"Parameters to monitor* are for performance purposes only; compliance monitoring parameters vary by state.
Cleanup standards are determined by the state.
3Costs h&de equjxnent, and operation and maintenance.
An "(average sStf" assurtes mWmal delays h corrective action and a moderately heterogeneous and permeable subsurface.
-------
&EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-025
October 1993
Soil Remediation For
UST Sites
Ex Situ Bioremediation:
Land Farming
Ex situ bioremediationland fanning (or land
treatment)is a technique for removing
biodegradable contaminants from excavated soil The
excavated soil and added nutrients are spread over a
lined treatment area. The area is periodically tilled to
facilitate the natural release of volatile organic
compounds (VOCs) and the biodegradation of
contaminants.
Land farming is effective on many soil types and a variety
of contaminants. It is also easy and inexpensive to design,
operate, and maintain.
Petroleum Types And Constituents
Fresh of weathered gasoline,* diesel, jet fuel, kerO-
sene, motor oil, heavy fuel oil, lubricating oils, and
crude oils , , -' ' "".-.'
Volatile organic compounds (VOCs) such, as , :
benzene, toluene, ethylbenzene, and xylene (BJEX);
residual semivolatile organic compounds (SVOCs)
such as poiynuclear aromatic hydrocarbons; and,,
nonvolatile constituents , : /
-------
Ex Situ Bioremediation: Land Farming
, :'.-,',! - :','' ' . ^^- . . , , ." .
- '" ':.' . '': .: . .''', " - , , . "''..'' ','.' ,,,,''. . "
Advantages
Limitations
System
Components
Wastestxeam
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs5
Simple and inexpensive to design, operate, and maintain
Effective on many soil types with a variety of
contaminants
Targets only biodegradable constituents
- Requires substantial space
Nutrients (fertilizer)
lined treatment cell with berms around the perimeter
Tilling equipment
lime (needed for low pH)
Irrigation equipment (optional)
Might need to treat or dispose of collected rainwater or
leachate
Soil contaminant concentration
MLcrobial population in soil
Soil pH, moisture, and nutrients
Leachate analysis (optional)
Treats > 90% of biodegradable constituents
For an ideal site3, -90% in 6 months to 2 years
For an average site4, ~90% in 6 months to 3 years
Longer time required to degrade heavier hydrocarbons
For an average site4, $20,000 to $70,000 ($20 to $70/cu yd)
Costs vary with the amount of soil to be treated and the
design of the containment cell
'"Parameters to monitor" are for performance purposes only; compliance monitoring parameters vary by state.
^Cleanup levels are determined by the state.
fyn "Heal site" assumes no delays in corrective action and a relatively homogeneous, permeable subsurface.
An "average site* assumes minftnal delays in corrective action and a moderately heterogeneous and permeable subsurface.
%osts include equipment, and operation and maintenance.
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v>EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-026
October 1993
Soil Remediation For
UST Sites
In Situ Passive
Biodegradation
(Natural Attenuation)
In situ passive biodegradation (natural attenuation) is
an approach for removing biodegradable contaminants
from soil. This method of remediation relies on
microorganisms to break down petroleum products in the
soil. It does not require the addition of oxygen or nutrients
to facilitate the process.
In situ passive biodegradation is extremely slow. It is most
appropriate when expedient remediation is not needed
and nearby receptors will not be affected by
contaminated soil. To date, few sites have been fully
remediated using this approach.
This technique offers low cost and minimal disruption to
business operations. In addition, this method generates
no wastestreams.
Petroleum Types And Constituents
Presh or weathered gasoline, diesel, jet fjiel, , ~ ,
kerosene ->r ' - { ^ " " " "~ 5 <, fv>,
* \ ^ '~ ~^',"
Volatile organic compounds (VOCs) such as , ^
benzene, toluene, ethylbenzene, andxylene (BTEX);
residual semivolatile organic compounds (SVOCs)
such as polynuclear aromatic hydrocarbons; and
nonvolatile constituents , ^
\
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In Situ Passive Biodegradation (Natural Attenuation)
Advantages
Costs substantially less than other methods
Eventually degrades volatile organic compounds (VOCs),
semivolatile organic compounds (SVOCs), and
nonvolatile organic compounds
Causes minimal disruption to business operations
Generates no wastestreams
Reduces potential for human contact with contaminated
soil or soil vapor
Limitations
Targets only biodegradable constituents
Is an extremely slow process
Requires sufficient nutrients, moisture, active
indigenous microbial population, and pH of 6-9 to
degrade contaminants
To date, few sites have been fully remediated
System
Components
Monitoring wells
Soil borings
Soil vapor probes
Wastestream
Treatment
None
Parameters to
Monitor1
Soil and groundwater contaminant concentrations
Oxygen and carbon dioxide
Cleanup Levels
and Timing2
Can achieve risk-based cleanup levels
Computer models project average remediation times of
50 to 200 years
Longer time required to degrade heavier hydrocarbons
Costs3
Costs vary depending on monitoring frequency and risk
assessments
Average risk assessment costs: $10,000 to $50,000
Average monitoring and reporting costs: $10,000 to
$60,000
"Parameters to monitor" are for performance purposes only; compliance monitoring parameters vary by state.
^Cleanup standards are determined by the state.
3Costs Include equipment, and operation and maintenance.
-------
&EPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403W
EPA510-F-93-027
October 1993
Soil Remediation For
UST Sites
Excavation And Off-Site
Treatment
Excavation and off-site treatment is a method for
removing contaminants from small volumes (less than
1,000 cubic yards) of soil that cannot be treated
effectively on site. Contaminated soil is excavated and
then treated. Typical treatment facilities include:
Low temperature thermal desorption facilities
Asphalt plants
Incinerators
This technique can be used with many different kinds of
soils and contaminants. It offers the benefit of actually
destroying contaminants rather than simply moving them
from one location to another.
Petroleum Types And ^ohstituents
« All types of,petrpleuni:products, , ,-
-------
Excavation And Off-Site Treatment
Advantages
limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs3
Easy and rapid to implement
Destroys contaminants
Minimizes long-term liability
Can reuse some types of soil for backfill
Effective on soils with varying concentrations and
constituents
Expensive for large volumes of soil with low contaminant
concentrations, high moisture, or clay content
Transportation costs can be high
System components can include:
Excavation equipment
Trucking equipment .
Equipment for sorting and sizing -
Rotary dryer or kiln
Thermal screw
Offgas treatment equipment
Air emissions equipment
Contaminant concentrations in pre- and post-treatment
soil
Can excavate to cleanup standards
>99% removal efficiency
Typically completed in 1 to 3 days
For an average site4, $70,000 to $180,000 ($70 to
$180/cu yd)
^Parameters to monitor" are for performance puiposes only; compliance monitoring parameters vary by state.
^Cleanup standards are determined by the state.
^Costs include equipment, and operation and maintenance.
4An ^average site" assumes mh'mal delays in corrective action and a moderately heterogeneous and permeable subsurface.
-------
k-xEPA
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
5403V/
EPA510-F-93-028
October 1993
Soil Remediation For
UST Sites
Excavation With Off-Site
Landfill Disposal
Excavation with off-site landfill disposal involves
removing small volumes (less than 1,000 cubic yards)
of soil with high concentrations of contaminants.
Contaminated soil is excavated and trucked to a landfill
for disposal
A limitation of this method is that it simply moves
contaminants to a landfill without treating or destroying
them. The technique also is subject to extensive land
disposal restrictions, which can vary between states and
counties. It is also subject to constraints in landfill capacity.
Petroleum Types And Constituents
All types of petroleum products
-------
Excavation With Of f -Site Landfill Disposal
Advantages
Limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs3
Easy and rapid to implement for small volumes of
soil
Simply moves contaminants; does not treat
Not cost-effective for large soil volumes or soil with low
contaminant concentrations
Cannot remove soil from under buildings or structures
t,
Might need to meet landfill acceptance criteria or
address landfill capacity constraints
Can pose long-term liability
Excavation equipment
Trucking equipment
Land disposal restrictions in some states/counties
Confirmatory soil sampling after excavation
Can excavate to cleanup standards
Concentrations will persist in landfill
Typically completed in 1 to 3 days
For an average site4, $45,000 to $200,000 ($45 to
$200/cu yd)
'"Parameters to monitor" are for performance purposes only; compliance monitoring parameters vary by state.
Cleanup standards are determined by the state.
"Costs include equipment, and operation and maintenance.
' 4M laverage sRa" assumes m'rtnal debys h correcBve action and a moderately heterogeneous, permeable subsurface.
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