Vapor Phase Remediation R1

2650 East 40th Avenue • Denver, Colorado 80205 • www.geotechenv.com2650 East 40th Avenue • Denver, Colorado 80205 • www.geotechenv.com

GROUND WATER SAMPLING • WATER LEVEL & PRESSURE • WATER SAMPLE FILTRATION • GROUND WATER REMEDIATION • GEOPHYSICAL MEASUREMENTSGROUND WATER SAMPLING • WATER LEVEL & PRESSURE • WATER SAMPLE FILTRATION • GROUND WATER REMEDIATION • GEOPHYSICAL MEASUREMENTS

VAPOR PHASE

REMEDIATION TECHNOLOGIES

The Nielsen Environmental Field School, Inc.

2012 North American Environmental Field Conference & Exposition



Agenda

• Introductions

• Vapor Intrusion Overview

• Vapor Phase Remediation Technologies

• Vapor Extraction

• Air Sparging





John Scripter

Technical Sales

[email protected]

603.654.6840



www.GeotechEnv.com

…a world leader in environmental technology,

manufacturing and product training since 1978.

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Audience Introductions

• Name

• Company name

• Experience with vapor phase remediation



What is Vapor Intrusion



The Facts About Vapor Intrusion

• 100,000 contaminated sites in US

in 2002*

• Contamination sources vary

• Problems associated with VI

– Health problems

– Decline in property values

– Liability for property owners

* Source: The National Research Council



Some Methods of Vapor Phase

Remediation

• Bioremediation

• Venting

• Bioventing

• Chemical Oxidation

• Excavation

• Dual Phase Extraction



At a given temperature, the mass of a gas dissolved in

a liquid is proportional to the pressure of the gas acting on the liquid.

Henry’s Law



What Happens When Boiling Eggs?

• To vaporize

contaminants

– Increase temperature

– Decrease pressure



Lower Pressure and Energy Required

Name

MolecularFormula

MeltingPoint (oC)

BoilingPoint (oC)

State at25oC

methane CH4 -183 -164 Gas

ethane C2H6 -183 -89 Gas

propane C3H8 -190 -42 Gas

butane C4H10 -138 -0.5 Gas

pentane C5H12 -130 36 Gas

hexane C6H14 -95 69 Gas

heptane C7H16 -91 98 Gas

octane C8H18 -57 125 Gas

nonane C9H20 -51 151 Liquid

decane C10H22 -30 174 Liquid

undecane C11H24 -25 196 Liquid

dodecane C12H26 -10 216 Liquid

eicosane C20H42 37 343 Liquid

triacontane C30H62 66 450 solid



What is Soil Vapor Extraction ?

Soil Vapor Extraction (SVE) extracts contaminants for the subsurface soil in a vapor form. Therefore , SVE systems are designed to remove contaminants that have a tendency to volatilize or evaporate easily such as volatile organic compounds (VOC’s) and some semi-volatile organic compounds ( SVOC’s) beneath the ground surface in the unsaturated zone IE: Vadose zone. By applying a vacuum through a series of underground wells, contaminants are pulled to the surface as vapor or gas.



Soil Vapor Extraction (SVE)

• Extracts contaminants from the subsurface soil in a vapor form

• Only works on contaminants which volatilize (or evaporate) easily

• Vacuum through underground wells

• Contaminants pulled to surface as vapor or gas

• Will not remove heavy oils, metals, PCB’s or dioxins



Soil Vapor Extraction

ApplicabilityThe target contaminants group for in situ SVE are VOC’s and some fuels. The technology is typically applicable only to volatile compounds with a Henry’s law constant greater than 0.01 or a vapor pressure greater than 0.5 mm Hg ( 0.02 inches Hg) Other factors, such as moisture content, organic content, and air permeability of the soil, will affect the SVE’s effectiveness. In situ SVE will not remove heavy oils, metals, PCB’s, or dioxins.

Because the process involves a continuous flow of air through the soil, however, it often promotes the in situ biodegradation of low-volatility organic compounds that may be present.




Design Considerations• Soil that has high percentage of fines and a

high degree of saturation will require higher vacuums

• Large screen intervals are required in extraction wells with highly variable permeability's or stratification, which may result in uneven delivery of gas flow from contaminated regions




Design Considerations (continued)• Soil that has high organic content or is extremely dry

has a high sorption capacity for VOC’s, which reduce removal rates

• SVE is not effective in the saturated zone; however, lowering the water table can expose more of the contaminated zone to the SVE ( LNAPLS)

• Exhaust air from the in situ SVE system may require treatment

• Residual liquids may require treatment or disposal




Data Needs• Depth and areal extent of contamination

• Concentration of contaminants

• Depth to water table

• Soil type and properties e.g., structure, texture, permeability, moisture content

• Pilot study: to determine radius of influence, flow rate, optimal vacuum and contaminant mass removal rates




LimitationsFactors that may limit the applicability and effectiveness of the process include:

• Soil that has high percentage of fines and a high degree of saturation will require higher vacuums ( $$$$$) and / or hinder on the system the operation

• Large screen intervals are required in extraction wells with highly variable permeability's or stratification, which otherwise may result in uneven delivery of gas flow from contaminated regions.




Limitations (continued)• Soil that has high organic content or is extremely dry

has a high sorption capacity for VOC’s, which reduce removal rates.

• SVE is note effective in the saturated zone; however, lowering the water table can expose more of the contaminated zone to the SVE ( LNAPLS)

• Exhaust air from the in situ SVE system may require treatment ($$$$)

• Residual liquids may require treatment or disposal( $$$$)



First Thing -Establish CFM

What are you measuring?

• CFM is a CFM .. Or is it ?

• SCFM, ACFM, ICFM… What does it mean ?



SCFM

Definition of SCFM– the term SCFM stands for Standard Cubic Feet Per Minute. It is referenced to a pre-specified atmospheric pressure, temperature, and relative humidity.

SCFM is referenced to 14.7 PSIA, 68 degrees F, and 0% relative humidity.

By specifying these parameters, the mass flow of compressed air and gas is clearly defined.



ACFM

Definition of ACFM– the term ACFM stands for Actual Cubic Feet Per Minute.

The ACFM is dependent on actual site conditions: PSIA, temperature, relative humidity.

By specifying these parameters, the mass flow of compressed air and gas is defined on actual site conditions.

The larger the difference between site conditions and SCF conditions, the larger the difference between SCF and ACF.



ICFM

Definition of ICFM– the term ICFM stands for Inlet Cubic Feet Per Minute.

The ICFM is dependent on the amount of air flow that enter in through the air filter on the equipment

Vacuum blowers / Pressure Blower manufacturer usually rated at SCFM conditions ….. BUT WHEN ARE YOU REALLY AT THOSE CONDITIONS ??

QUESTION: When you are measuring CFM, are you correcting for the location conditions or are you assuming it is SCFM because the meters says it reads in SCFM ?



BAROMETRIC PRESSURE

vs. ALTITUDE

FEET PSIA IN HG

0 (sea level) 14.70 29.92

1000 14.16 28.86

2000 13.66 27.82

3000 13.16 26.81

4000 12.68 25.85

5000 12.22 24.89

6000 11.77 23.98

7000 11.33 23.09

8000 10.91 22.22

9000 10.50 21.38

10000 10.10 20.58




Several blower options available depending on flow and vacuum requirements….including Centrifugal Fans, Regenerative, Rotary Lobe IE: Positive Displacement, Rotary Vane, Rotary Claw, Liquid Ring (Dual Phase – Multi-Phase Extraction {MPE} )

CONFIGURATIONS AVAILABLE

• Compact skid mounted designs

• Trailer Mounted and Enclosures available

• Complete systems including knockout drums, effluent pumps, temperature and vacuum switches, and controls



Soil Vapor Extraction “Rule of Thumb”

Blower Sizing Application

Blower CFM INHGG

Equipment Flow Range Vacuum Range

Centrifugal Fan 400-1500 1-3

Regenerative 20- 300 2-7

Rotary Lobe 50- 1000 5-15

Rotary Vane 5- 50 5- 28

Rotary Claw 30- 1000 5- 28

Liquid Ring 20- 1000 15- 28






• Complete systems including knockout drums, effluent pumps, temperature and vacuum switches, and controls

• A surface liner or clay cap gives control over the path of airflow.



Centrifugal Fan

Vacuum Application



Regenerative SVE in enclosure



Rotary Lobe

Vacuum Application



Rotary Vane

Vacuum application



Rotary Claw SVE Skid



Liquid Ring System

Vacuum Application for Multi- Phase



What is Air Sparging?

Since SVE cannot remove contaminants in the

saturated zone that lies below the water table,

Air Sparging technology pushes air into the

saturated zone to help flush (bubble) the

contaminants up into the unsaturated zone

where the SVE extraction wells can remove

them.



Air Sparging

• The process of blowing air directly into the ground water.

• As the bubbles rise, the contaminants are removed from the groundwater by physical contact with the air (i.e., stripping).

• Air and contaminants are carried up into the unsaturated zone (i.e., soil).

• As the contaminants move into the soil, a soil vapor extraction system is usually used to remove vapors.



Air Sparging

Applicability & LimitationsFor Air Sparging to be successful, the soil in the saturated zone must be loose enough to allow injected air to readily escape up into the unsaturated zone. Sites where coarse grained soil, sand, gravel are good candidates. Tight clays and poor permeable soil only inhibit the effectiveness of this technology. You can spend a lot of money on electricity and accomplish very little when the soil are not conducive for Air Sparging technology.

As with SVE, the added benefit of Air Sparging is that it provides an oxygen source which helps stimulate aerobic biodegradation.



Before you can size an Air Sparge

Blower – Do a pilot test• As with the SVE pilot, you will need to know just

how much air flow and PSIG will be required to push the air into the formation.

• Also when incorporating the technology with an SVE system how much is enough ? Too much ?

• Rule of thumb: size the Air Sparge unit air flow at 1/3rd to 1/5th of the SVE system air flow. You will want to be able to capture the vapors and not allow for off-site migration.



Air Sparging an Example

• Easier at warmer temperatures.

• Effected by moisture, organics, air permeability of the soil.

• Ineffective for heavy oils, metals, PCB’s or dioxins.

• Enhances biodegradation of low-volatility organic compounds.

• Principles based on Henry’s Law.



Air Sparge Blowers

Several blower options available depending on flow and pressure requirements

Configurations Available



• Complete systems to work in conjunction with an SVE System



Air Sparge “Rule of Thumb”

Blower Sizing Application Blower CFM PSIG

Equipment Flow Range Pressure Range

Regenerative 20- 300 < 4

Rotary Lobe 50- 1000 1-15

Rotary Vane 5- 50 1- 20

Rotary Claw 50- 350 5- 30

Rotary Screw 20- 200 +30- 150



Regenerative



Rotary Lobe



Rotary Vane



Rotary Vane

(Dual System)



Rotary Claw

Pressure Application



Rotary Screw



For Example:

SV and Sparge Together

Graphic Source: Environmental Geoscience Environmental Science in the 21st Century Textbook by Robert Stewart

Vadose Zone



Carbon Treatment

• May be required to treat the off-gas.

• 100 lb up to 20,000 lb vessels available

• Reactivated carbon, virgin carbon, coconut shell media and other types of media available depending on your application

• Low pressure and high pressure units

• 50 lb bags for media replacement available



Carbon Treatment

• Liquid Phase vessels

• 100 lb up to 20000 lb vessels available






Liquid Phase Carbon Vessels



Carbon Treatment

• Vapor Phase vessels

• 100 lb up to 20000 lb vessels available






Vapor Phase Carbon Vessels



Plume Eater

• Soils are flushed with oxygenated groundwater

• Pulls from the groundwater surface and re-injects, oxygenated water deep in the formation, creating convection currents

• Accelerates bio-remediation

• Maximum efficiency with minimal power

• No sub-surface moving parts

• Works in a variety of soil types

• No net change in groundwater volume

• Options available for use with other gases

• In Situ Technology – No re-injection permits or water treatment extraction required, water never leaves the subsurface



Summary

• Get proper data

• Choose right blower for your application

• Geotech can help in the discussion

• Let’s get coffee



Many companies can provide the

equipmentto keep these industries within

environmentally acceptable standards

… but Geotech provides more than that.



…your partner in

creating the

environmentally

safe planet

of the future!





John Scripter

Technical Sales

[email protected]

603.654.6840

Vapor Phase Remediation R1

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