Successful On Site Bioremediation of Fuel-Contaminated Soil at - - PowerPoint PPT Presentation

Successful On Site Bioremediation of Fuel-Contaminated Soil at CFS-Alert

David Juck1, Danielle Beaumier1, Sylvie Sanschagrin1, Etienne Yergeau1, Andrew Tam2, Chris McRae2, Don Kovanen2, Drew Craig2, and Charles W. Greer1

1National Research Council Canada, Energy, Mining and Environment 2National Defence, 8 Wing/CFB Trenton Environmental Management

April 26, 2016 2016 RPIC Federal Contaminated Sites National Workshop

Presentation Outline

• Site description of CFS-Alert
• Challenges in the Arctic
• Feasibility study
• Ex situ biopile implementation
• Opening the ‘Black Box’
• Conclusions

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CFS-Alert

CFS-Alert

• Built in 1950 as a weather station, Alert became a

Canadian Military Communications Research Facility in

• 1956. At its peak of activity in the 1970’s, 200 military staff

were stationed year around at CFS-Alert.

• Currently about 50-80 staff, mostly civilian contractors
• Our work there
• Started in 2006
• Site characterization and delineation
• In situ and ex situ bioremediation

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CFS-Alert

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Late August at CFS-Alert

Challenges in the Arctic

• Temperature
• Very short treatment window

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• 40
• 30
• 20
• 10

10 February April June August October December

• Average temperatures in June, July and August of -0.8°C,

3.3°C and 0.8°C, respectively.

Challenges in the Arctic cont.

• Desert conditions
• Total average annual precipitation is 153.8 mm (mostly in July,

August and September)

• Approximately the same as one month in Montreal
• Permafrost
• Impermeable barrier - can be a benefit or problem
• Contain the contamination to upper 1m of soil
• Horizontal movement of contamination during spring freshet
• Stability of infrastructure is based on the stability of the permafrost

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Challenges in the Arctic cont.

• Logistics
• Limited infrastructure
• Limited heavy equipment access and operator time
• Limited experience with remediation work
• All materials have to come in by airplane
• Can take 2 years to move material to site
• Site history
• Continual rotation of staff means little to no ‘corporate memory’ of

previous activities or installations

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CFS-Alert during heyday

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Biodegradation Feasibility Study

Feasibility Study – ‘Worm Farm Soil’

• Diesel contaminated

soil

• Alternate treatments

previously tried

• Nutrient

amendments

• 20-20-20 (N-P-K)
• MAP (mono-

ammonium phosphate)

• MAP most effective

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Ex Situ Biopile

2006 Diesel Pipeline Spill

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Biopile Construction

• Biopile treatment area built in 2007 to treat a diesel spill
• 40 x 100 m
• Sand foundation, geotextile, impermeable membrane and

sand base, berm approximately 2.0 m.

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Contaminated Soils

2006 Diesel Pipeline Spill

• Breach in diesel pipeline late September 2006
• Small amount of soil excavated at far end of spill
• Majority of soil excavated during 2007 field season
• Approximately 2,000 m3 of soil in total

Auxiliary Power Plant Spill 2007

• Spill during re-filling of fuel tank
• Excavation within 24 hours of spill event
• Approximately 500 m3 of soil excavated

Cat House Managed soils

• Contaminated soils from 3 areas excavated and combined (2011)
• Approximately 100 m3 of soil
• Contamination at least 12 years old

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Biopile Treatment

• Soil windrowed
• T=0 samples collected
• MAP treatment started in 2007
• ca. 250 kg MAP/year, turning once per year
• < 50 mg MAP/kg soil over total treatment
• Control pile – no MAP

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PHC Mineralization Activity

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10 20 30 40 50 60 70

LO-1 LO-2 LN-1 LN-2 LC S-1 S-2 S-3 S-4 HF sterile control

A 10 20 30 40 50 60 5 10 15 20 25 30 35 40 Mineralization (%) Time (days) B

2010

10 20 30 40 50 Mineralization (%) A 10 20 30 40 10 20 30 40 50 60

LO-1 LO-2 LN-1 LN-2 LC-1 SO-1 SN-1 SN-2 sterile control

Time (days) B

2008

F2 Concentrations – 2006 and 2007 Spills

• 2015 F2 average for all

biopile samples collected was 112 mg/kg (guideline

• f 260 mg/kg)
• No hotspots within biopile
• No significant changes in

control pile concentrations

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F2 Concentrations (mg/kg)

F2 Biopile Control

‘Cat House’ Managed Biopile

• Soils excavated from 3

different areas at Alert

• All spills over 15 years old
• F2 Starting average ca.

2,000 mg/kg

• Average F2 concentration

in August was 200 mg/kg

• One hotspot at guideline

concentration (414 mg/kg)

• ‘Aged’ soil responding very

rapidly to treatment

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500 1000 1500 2000 F2 Concentrations (mg/kg)

F2

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Opening the ‘Black Box’

Who’s there? What are they doing?

• We know that the PHCs are being degraded due to the

treatment system

• What are the population dynamics at play?
• What biodegradation pathways are being stimulated?
• Is the treatment targeting the organisms we want?
• Molecular biological methods are now available to answer

these questions

• Targeting the DNA and RNA of the organisms present in the system

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Metagenomic Analysis – Population Changes

• Decrease in diversity upon

contamination

• High initial numbers of

Gammaproteobacteria, decreased over time

• increase over time in

Actinobacteria

• Main Gammaproteobacteria

are Pseudomonas species

• Low numbers of

Pseudomonas in pristine soil

• Increased dramatically

following contamination

• Dynamic system

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Quantitative PCR

• Following the gene copy

number for alkane monooxygenase

• Important first step in alkane

biodegradation

• Significant initial increase in

Pseudomonas version

• Delayed increase in

Rhodococcus version

• Similar trend when gene

expression followed

• Similar trend observed with

ndoB (for aromatics biodegradation)

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Gene Copy Number (copies/ng DNA) Year

alkB (PspEu5&Pp) alkB1 (Q15)

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Conclusions

Conclusions

• Bioremediation of PHCs is a viable option under Arctic

conditions

• Simple ‘passive’ biopile system effective on new and aged

contamination

• More is not necessarily better when it comes to treatment

application

• More frequent application of low concentration nutrients keeps the

degraders happy

• Inhibition of activity with high concentrations of nutrients
• Cost effective solution
• Estimated at $45/m3
• Very active and dynamic indigenous microbial community

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Thank you

David Juck, Ph.D. Research Officer Tel: 514-496-5297 david.juck@cnrc-nrc.gc.ca www.nrc-cnrc.gc.ca