HIGH VACUUM MULTI-PHASE EXTRACTION CASE STUDIES MWCC CONFERENCE - - PowerPoint PPT Presentation

▶

Aug 30, 2023 27 likes •308 views

HIGH VACUUM MULTI-PHASE EXTRACTION CASE STUDIES MWCC CONFERENCE JULY 2019 High Vacuum Multi-Phase Extraction Soil vapor and groundwater extraction and treatment system Truck Mounted 450 CFM Air Flow 29 Inches Hg Max Vacuum

SLIDE 1

HIGH VACUUM MULTI-PHASE EXTRACTION – CASE STUDIES

MWCC CONFERENCE JULY 2019

SLIDE 2

High Vacuum Multi-Phase Extraction

§ Truck Mounted § 450 CFM Air Flow § 29 Inches Hg Max Vacuum § 50 GPM Water Extraction § Can extract from up to 6 wells at a time. § Soil vapor and groundwater extraction and treatment system

SLIDE 3

High Vacuum Multi-Phase Extraction Case Studies

§ Shallow LNAPL Zone § Deep Complex LNAPL Zonese

SLIDE 4

Shallow LNAPL Zone

§ Active Gas Station (Since Prior to 1988)

§ 3-12,000 gallon USTs

§ Former Gas Station and USTs

§ 2-4,000 gallon, 1-300 gallon waste oil UST § Removed in 1988 – Separate release R1988 given NFA in 2014

§ Known Release – 2008 § Geology

§ Silty Clay § Bedrock - 8-18 feet bgs § Groundwater flow to N/NW

SLIDE 5

LNAPL

§ Known Release (2008) – ~4500 Gallons – North dispenser § Measured in 3 Existing Wells After Release

§ MW-9, MW-10, MW-16 – Maximum thickness – 4.15 feet – MW-10

§ Recovery Wells Installed – November 2008

§ Measured in all 5 RWs – Maximum thickness – 4.06 feet – RW-2

§ Generally measured between 4.3 and 12.55 feet btoc (Intermittent)

SLIDE 6

Previous LNAPL Removal

§ LNAPL Gallons Removed Unknown § 10 MDPE events – October 2008 – February 2009 – 7,033 Gallons of Groundwater § Passive Recovery – May 2009 – October 2012 – ~44 gallons § Reduction in Thickness – LNAPL Remained in MW-9, MW-10, MW-16, RW-2, RW-3, RW-4, RW-5

SLIDE 7

High Vacuum Multi-Phase Extraction January 2018 – March 2018 (49 Days)

§ Measured LNAPL (Intermittent)

§ Prior to HVDPE: MW-9, MW-10, RW-4, RW-5 § Additional During HVDPE: MW-23

§ Six Extraction Wells (Different Combos, 4 Wells at a Time)

§ MW-10, MW-16, RW-2, RW-3, RW-5, RW-6

SLIDE 8

High Vacuum Multi-Phase Extraction Considerations

§ Stinger Placement

§ Initially – DTW/LNAPL

r 1 foot below

§ Final – Bottom of well

§ Measured Depth to LNAPL

§ Beginning (4 wells): 7 – 11.5 feet btoc § During (1 additional well): 8.5 – 9.5 feet btoc

§ Total Depth of Wells with LNAPL

§ 11 – 14 feet

SLIDE 9

High Vacuum Multi-Phase Extraction – Results

§ System Parameters

§ Air Flow: 125-167 CFM

Increase as saturated zone exposed (vapor increase) and LNAPL reaches MEP

§ Vacuum: 15-18 Inches Hg

Increase as saturated zone exposed (vapor increase); Consistent as LNAPL reaches MEP

§ Influent Conc: ~1,300 ppmv – 9,900 ppmv

High when saturated zone exposed

§ 131,590 Gallons of Groundwater Removed (2,676 Gallons/Day) § Avg. 1653.26 (Equivalent) Gallons of Hydrocarbons Removed (33.8 Gallons/Day) § Drawdown ROI/Vacuum ROI of Up to 60 Feet

SLIDE 10

High Vacuum Multi-Phase Extraction – Results

§ Stinger Depth, Well Combinations § Saturated Depths – SVE § LNAPL Mobilized § Periodic Increasing Trend – Saturated zone Dewatered (Dry wells) § Decreasing Trend at End § No LNAPL Remains in Wells

2,000 4,000 6,000 8,000 10,000 12,000 1/16/18 0:00 1/17/18 0:00 1/18/18 0:00 1/19/18 0:00 1/20/18 0:00 1/21/18 0:00 1/22/18 0:00 1/23/18 0:00 1/24/18 0:00 1/25/18 0:00 1/26/18 0:00 1/27/18 0:00 1/28/18 0:00 1/29/18 0:00 1/30/18 0:00 1/31/18 0:00 2/1/18 0:00 2/2/18 0:00 2/3/18 0:00 2/4/18 0:00 2/5/18 0:00 2/6/18 0:00 2/7/18 0:00 2/8/18 0:00 2/9/18 0:00 2/10/18 0:00 2/11/18 0:00 2/12/18 0:00 2/13/18 0:00 2/14/18 0:00 2/15/18 0:00 2/16/18 0:00 2/17/18 0:00 2/18/18 0:00 2/19/18 0:00 2/20/18 0:00 2/21/18 0:00 2/22/18 0:00 2/23/18 0:00 2/24/18 0:00 2/25/18 0:00 2/26/18 0:00 2/27/18 0:00 2/28/18 0:00 3/1/18 0:00 3/2/18 0:00 3/3/18 0:00 3/4/18 0:00 3/5/18 0:00 3/6/18 0:00 3/7/18 0:00 3/8/18 0:00 3/9/18 0:00 3/10/18 0:00 3/11/18 0:00

Vapor Inlet Concentration (ppmv)

Total Inlet Vapor Concentration Vs. Time

Dilution Stinger Depth Change Well Change and Stinger Depth Change Saturated Zone Exposed Saturated Zone Exposed/ Removal of LNAPL

SLIDE 11

High Vacuum Multi-Phase Extraction – Water Levels

9 9.5 10 10.5 11 11.5 12 1/16/2018 1/20/2018 1/24/2018 1/28/2018 2/1/2018 Depth to Water (feet)

MW-16

6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 1/16/2018 1/20/2018 1/24/2018 1/28/2018 2/1/2018 Depth to Water (feet)

MW-23

8 8.5 9 9.5 10 10.5 11 12/11/17 0:00 1/20/18 0:00 3/1/18 0:00 4/10/18 0:00 Depth to Water (feet)

MW-26

10 10.5 11 11.5 12 12.5 13 13.5 14 14.5 15 1/16/2018 1/20/2018 1/24/2018 1/28/2018 2/1/2018 Depth to Water (feet)

RW-5

§ Observation Wells

§ Dropped up to 3.34 feet

§ Extraction Wells

§ Dropped > 1 foot (1 week later)

SLIDE 12

October 2008 – February 2009 May 2009 – October 2016 March 2018 – April 2019

SLIDE 13

Deep Complex LNAPL Zones

§ Active Gas Station (Since 1950) – 1- 30,000 Gallon Compartmentalized UST § Former UST Basin § 1-4,000 gallon, 2-6,000 gallon and 1-8,000 gallon (Removed 1995) § Impact found in 1995 § Unknown release date and amount § Geology § Silty clay to sandy clay with sand and gravel lenses throughout § Bedrock – 25-45 feet bgs § Groundwater flow variable

SLIDE 14

LNAPL

§ First discovered in 1999 in MW-2 (2.0 feet) § Historically identified in 11 On-Site and Off-Site Wells (Intermittent) § Maximum historical thickness in MW- 15, July 2010 – 7.51 feet, DTW – 28.65 feet § Generally measured at depths of between 21 feet – 35 feet in wells (depending on location)

SLIDE 15

Previous LNAPL Removal

§ ~213 gallons removed since 1999

§ Manual Recovery (30+) – ~ 21 gallons § Mobile Dual Phase Extraction (MDPE) – 5 events between 2012 and 2016 – ~183 gallons § Active Skimming System (Pilot on MW-15 and MW-16) – Between 2013 and 2015 – ~9 gallons § Periodic Passive Recovery

§ > 50% reduction in MW-2 and MW-15 – Greater than 1 foot LNAPL remained

nsite

SLIDE 16

~5 – 10 feet ~25 – 35 feet

*Some areas of 20 feet

Laser Induced Fluorescence (LIF) Survey – 2012

§ 21 borings completed – 31 to 42 feet (refusal) § Multiple discontinuous zones (shallow and deep); above and below groundwater surface § Monitoring/Recovery wells screened in shallow and deep LNAPL zones § Estimated volume of LNAPL body – 2,332 gallons

SLIDE 17

7-Day Pilot Test (December 2016)

§ Considerations and Plan § LNAPL Measured in MW-12, MW-26, RW-5 (December 2016) § LNAPL Zones (LIF Data) § Extraction Wells (Six at a Time, Different Combos)

MW-2, MW-12, MW-15, MW-16, MW-26,

RW-5

SLIDE 18

7-Day Pilot Test Considerations

§ Wells generally screened in deep LNAPL zone § LNAPL Zones

§ Shallow (Limited): 5-10 feet bgs § Deep: 25-35 feet bgs

§ Measured Depth to LNAPL

§ MW-12 – 31.28 ft, TD – 35 ft § MW-26 – 31.06 ft, TD – 40 ft § RW-5 – 24.75 ft, TD – 37 ft

§ Role of Stinger Depth

§ Initial – DTW/LNAPL in Wells § Final – Bottom of LNAPL Zone/Bottom of Well

SLIDE 19

7-Day Pilot Test – Results

§ System Parameters

§ Air Flow: 34 – 78 SCFM (Highly Variable)

Initial highest air flow (multiple wells)
Decrease with reduction in wells and as saturated zone exposed

§ Vacuum: 21 – 25 Inches Hg

Remained consistent

§ Influent Conc: ~4,000 – 13,000 ppmv (Some Dilution)

High when saturated zone exposed

§ 26,920 Gallons of GW Removed and Treated § Average of 203.36 Gallons of Hydrocarbons Removed § Water Levels (Observation and Extraction Wells) – Dropped > 1 foot § Drawdown ROI/Vacuum ROI – Up to 45 Lateral Feet

SLIDE 20

7-Day Pilot Test - Results

§ Stinger Depth § Well Combinations § Dilution § Saturated Depths – SVE § LNAPL Mobilized § Increasing Vapor Concentrations – Saturated Zone Exposed § LNAPL Remained in Subsurface

2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 12/4/16 18:00 12/5/16 12:00 12/6/16 6:00 12/7/16 0:00 12/7/16 18:00 12/8/16 12:00 12/9/16 6:00 12/10/16 0:00 12/10/16 18:00 12/11/16 12:00 12/12/16 6:00 12/13/16 0:00

Vapor Inlet Concentration (ppmv)

Vapor Inlet Concentration (ppmv) Vs. Time

Dilution

Saturated Zone Exposed Well Change/ Stinger Depth Change Saturated Zone Exposed Saturated Zone Exposed Well Change/ Stinger Depth Change Initial Stinger Depth - ~26.5-32.5 ft Final Stinger Depth - ~33.5-38.5 ft

SLIDE 21

High Vacuum Multi-Phase Extraction Event March 2018 – July 2018 (134 Days)

§ Measured LNAPL (Intermittent)

§ Prior to HVME: MW-2, MW-12, MW-15, MW-16, MW-26, RW-4 § Additional During HVME: MW-21, MW-22

§ Nine extraction wells (different combos, 6 wells at a time)

§ MW-2, MW-12, MW-15, MW-16, MW-21, MW- 22, MW-26, RW-2, RW-5

SLIDE 22

High Vacuum Multi-Phase Extraction Event Considerations

§ Measured Depth to LNAPL

§ Beginning (6 wells): 31 – 33 feet § During (2 addtl wells): 38 – 41 feet

§ Total Depth of Wells with LNAPL

§ 35 – 46 feet

§ Stinger Placement

§ Bottom of LNAPL zone and/or bottom of well (pilot test data)

SLIDE 23

High Vacuum Multi-Phase Extraction Event – Results

§ System Parameters

§ Air Flow: 155 – 260 SCFM (Consistent 180 – 185 CFM)

Variable in beginning as saturated zone exposed
High when wells added

§ Vacuum: 15 – 22 Inches Hg (Consistent 21 – 22 Inches Hg)

Variable in beginning as saturated zone exposed
Low when wells added

§ Vapor Conc: 6,000 – 20,000 ppmv (No Dilution)

High as saturated zone exposed

§ Average of 17,689.7 Gallons (Equivalent) of Hydrocarbons Removed (131 GPD) § 555,020 Gallons of GW Removed (4,111 GPD) § Drawdown ROI/Vacuum ROI – Up to 55 Feet

SLIDE 24

High Vacuum Multi-Phase Extraction – Results

§ Stinger Depth § Well Combinations § Saturated depths – SVE § LNAPL Mobilized § Increasing Trend of Vapor concentrations – Saturated zone Dewatered § LNAPL Remains in Wells

§ Reduced Thickness § Reduced Occurrence

5,000 10,000 15,000 20,000 25,000 3/1/18 0:00 3/11/18 0:00 3/21/18 0:00 3/31/18 0:00 4/10/18 0:00 4/20/18 0:00 4/30/18 0:00 5/10/18 0:00 5/20/18 0:00 5/30/18 0:00 6/9/18 0:00 6/19/18 0:00 6/29/18 0:00 7/9/18 0:00 7/19/18 0:00 7/29/18 0:00 8/8/18 0:00

Vapor Inlet Concentration (ppmv)

Vapor Inlet Concentration (ppmv) Vs. Time

Well Change Well Change Saturated Zone Exposed Saturated Zone Exposed

SLIDE 25

High Vacuum Multi-Phase Extraction – Water Levels

36.00 36.50 37.00 37.50 38.00 38.50 39.00 39.50 40.00 40.50 3/1/2018 4/10/2018 5/20/2018 6/29/2018 8/8/2018

MW-13

33.00 34.00 35.00 36.00 37.00 38.00 39.00 3/1/2018 4/10/2018 5/20/2018 6/29/2018 8/8/2018

MW-14

36.00 37.00 38.00 39.00 40.00 41.00 42.00 43.00 3/1/2018 4/10/2018 5/20/2018 6/29/2018 8/8/2018

MW-21

Series1 28.00 30.00 32.00 34.00 36.00 38.00 3/1/2018 4/10/2018 5/20/2018 6/29/2018 8/8/2018

MW-9

Series1

§ Observation Wells

§ Dropped up to 13.25 feet – Some wells dry

§ Extraction Wells

§ Dropped up to 5.62 feet

SLIDE 26

March 2019 – DTW ~ 2 feet from SWL (1 Well) Max LNAPL Prior to HVDPE (11 Wells) July 2018 – October 2018 – DTW > 5 feet low (5 Wells)

SLIDE 27

High Vacuum Multi-Phase Extraction Case Study Conclusions

§ Effective at Reducing/Removing LNAPL within LNAPL Plume and Adjacent § Good Radius of Influence (Site Specific) § Previously Saturated Zones Exposed to SVE § LNAPL Mobilized

SLIDE 28

Thank you!

The Members of the ATC Team