Remediation of Oil Polluted Soil in the Arctic...Remediation of Oil Polluted Soil in the Arctic –...

Remediation of Oil Polluted Soil in

the Arctic One-Day Conference

Summary

Remediation of Oil Polluted Soil in the Arctic – Conference Summary 2

FES Project number: 2018/001185

FES project manager: Birgitte Weber Blicher

Consultant: NIRAS

Consultant project number: 10400881

Reported by: Charlotte Riis

Quality assurance by: Søren Rygaard Lenschow


1. INTRODUCTION ................................................................................................. 6

1.1 Background of the report ...................................................................................... 6

2. KEYNOTE ........................................................................................................... 8

3. LANDFARMING .................................................................................................. 9

3.1 The practical implementation ................................................................................. 9

3.1.1 Background and objective .................................................................................. 9

3.1.2 Method ............................................................................................................ 9

3.1.3 Results .......................................................................................................... 10

3.1.4 Conclusion ...................................................................................................... 11

3.2 Microbial oil degradation in arctic soil .................................................................... 11

3.2.1 Background and objective ................................................................................ 11

3.2.2 Method .......................................................................................................... 12

3.2.3 Results .......................................................................................................... 12

3.2.4 Conclusion ...................................................................................................... 12

3.3 Chemical fingerprints in oil analyses ..................................................................... 12

3.3.1 Background and objective ................................................................................ 12

3.3.2 Method .......................................................................................................... 13

3.3.3 Results .......................................................................................................... 13

3.3.4 Conclusion ...................................................................................................... 14

3.4 Discussion (Q&A) ............................................................................................... 14

4. BIOREMEDIATION ........................................................................................... 15

4.1 Background and objective ................................................................................... 15

4.1.1 Eureka High Arctic Weather Station ................................................................... 15

4.1.2 Alert .............................................................................................................. 15

4.2 Method ............................................................................................................. 16

4.2.1 Eureka – In Situ Biopile.................................................................................... 16

4.2.2 Alert – Ex situ biopile ....................................................................................... 16

4.2.3 Alert – Bio barrier............................................................................................ 16

4.3 Results.............................................................................................................. 16

4.3.1 Eureka – In Situ Biopile.................................................................................... 16

4.3.2 Alert – Ex situ biopile ....................................................................................... 17

4.3.3 Alert – Bio barrier............................................................................................ 17

4.4 Conclusion ......................................................................................................... 17

4.5 Discussion (Q&A) ............................................................................................... 17

5. OVERVIEW OF REMEDIATION TECHNIQUES IN ANTARCTICA .......................... 19


5.1.1 Casey ............................................................................................................ 19

5.2 Method ............................................................................................................. 19

5.2.1 Casey – Reactive barrier .................................................................................. 19

5.2.2 Casey - Biopiles .............................................................................................. 20

5.3 Results.............................................................................................................. 20

5.3.1 Casey - Reactive barrier ................................................................................... 20

5.3.2 Casey - Biopiles .............................................................................................. 20

5.4 Conclusion ......................................................................................................... 20

5.5 Discussion (Q&A) ............................................................................................... 20

6. BIOPILES IN ANTARCTICA .............................................................................. 21



6.2 Method ............................................................................................................. 21

6.3 Results.............................................................................................................. 21

6.3.1 Experience with establishment of biopiles ........................................................... 21

6.3.2 Results from operation of biopiles ...................................................................... 22

6.4 Conclusion ......................................................................................................... 22

6.5 Discussion (Q&A) ............................................................................................... 22

7. IN SITU REMEDIATION IN NORTH SWEDEN .................................................... 24


7.1.1 Vittangi petrol station ...................................................................................... 24

7.1.2 Piteå fuel depot ............................................................................................... 24

7.1.3 Stöde trucks filling station ................................................................................ 24

7.2 Method ............................................................................................................. 24


7.2.2 Piteå fuel depot ............................................................................................... 24

7.2.3 Stöde truck filling station ................................................................................. 24

7.3 Results.............................................................................................................. 25


7.3.2 Piteå fuel depot ............................................................................................... 25

7.3.3 Stöde truck filling station ................................................................................. 25

7.4 Conclusion ......................................................................................................... 25

7.5 Discussion (Q&A) ............................................................................................... 25

8. ELECTROKINETIC REMEDIATION ..................................................................... 26


8.2 Method ............................................................................................................. 26

8.2.1 EK-BIO .......................................................................................................... 26

8.2.2 EK-ISCO/EK-TAP ............................................................................................. 26

8.2.3 Suspended EK................................................................................................. 27

8.2.4 EK in Grønnedal?............................................................................................. 27

8.3 Conclusion ......................................................................................................... 27

8.4 Discussion (Q&A) ............................................................................................... 27

9. CHEMICAL OXIDATION .................................................................................... 28


9.2 Method ............................................................................................................. 28

9.3 Results and conclusion ........................................................................................ 28

9.4 Discussion (Q&A) ............................................................................................... 29

10. THERMAL REMEDIATION ................................................................................. 30

10.1 Background and objective ................................................................................ 30

10.2 Method .......................................................................................................... 30

10.3 Results .......................................................................................................... 30

10.4 Conclusion ...................................................................................................... 30

10.5 Discussion (Q&A) ............................................ Fejl! Bogmærke er ikke defineret.

11. REMEDIATION OF FUEL OIL AT LIGHTHOUSES ................................................ 31


11.2 Method .......................................................................................................... 31

11.3 Conclusion and future activities ......................................................................... 31

11.4 Discussion (Q&A) ............................................................................................ 31


12. CLOSING OF COAL MINE .................................................................................. 32


12.2 Method .......................................................................................................... 32

12.3 Results .......................................................................................................... 32

12.4 Conclusion and reflexions for future process ....................................................... 32

12.5 Discussion (Q&A) ............................................................................................ 33


1. Introduction

1.1 Background of the report

On 15 March 2018, the Danish Ministry of Defence Estate Agency held a conference concerning

remediation methods for cleaning up oil pollution in the Arctic: Remediation of Oil Polluted Soil

in the Arctic.

The purpose of the conference was to identify the best ways to deal with oil pollution in the

Arctic. The Ministry of Defence requires this knowledge in order to assess potential remediation

projects at the Danish Defence base areas in Greenland, specifically including at Grønnedal on

the south eastern coast of Greenland. As the temperature, logistics and hydrogeological condi-

tions in Greenland are so different from temperate areas as Denmark, the methods for han-

dling oil contamination usually applied by the Danish Defence cannot necessarily be used in

Greenland.

The purpose of this initiative was to invite speakers from all over the world to the conference

to provide inspiration and share experience in handling oil pollution in the Arctic, Antarctica

and under Arctic conditions in northern Scandinavia.

This report is a summary of the conference speeches and a summary of the discussions follow-

ing the individual speeches. The report will be used by both the Ministry of Defence and the

Greenland authorities to assess the viability of the individual methods in Grønnedal.

In Table 1.1 the conference programme is summed up.


Summa-

rized in

section

no.

Speech title Speaker

2 Key-Note speech Niels Henrik Hedegaard

(Danish Ministry of Defence)

3 Landfarming - Theory and practice. An exam-

ple from Northeast Greenland.

Jan H. Christensen (Copenha-

gen University), Anders R.

Johnsen (GEUS), Peter Henrik-

sen (NIRAS)

4 Bioremediation of Petroleum Hydrocarbons in

the Canadian Arctic.

David Juck (National Research

Council, Canada)

5 An Overview of Hydrocarbon Remediation

Techniques and Activities Conducted at Aus-

tralian Antarctic Stations.

Tim Spedding (Australia Ant-

arctic Division)

6 Building and Operating Biopiles to Remediate

Fuel Contaminated Soil in Antarctica.

Rebecca Mc Watters (Australia

Antarctic Division)

7 Case studies of Successful In situ Treatment of

Oil Contamination Under Arctic Conditions

Jonny Bergman (RGS Nordic,

Sweden)

8 Potential of Electrokinetic Remediation of Oil

Contaminated Soils.

Lisbeth M. Ottosen (DTU)

9 Effective Remediation of Petroleum Hydrocar-

bons in Water-Borne Deposits at Grønnedal

Using Chemical Oxidation.

Jarl Dall-Jepsen (COWI)

10 In situ Thermal Treatment in Arctic? Kim Jensen (Arkil)

11 Remediation of Fuel Leaks from Remote Light-

houses in Northern Norway.

Liv Marit (Rambøll Norway)

12 Project Management of the Closure of Coal

Mining in Svalbard.

Frank Holmgaard (Rambøll

Norway)

Table 1.1 Speeches at the conference on 15 March 2018 and chapter numbers in this report in

which each speech is summarized.


2. Keynote

Key-Note Speech

By Deputy Permanent Secretary of State for Defence Niels Henrik Hedegaard, The Danish Min-

istry of Defence

The conference will focus on the status and trends of remediation of oil contaminations aiming

to reduce the risks for the Arctic ecosystem and its inhabitants. Today a number of experts will

share their experiences with us in order to increase our knowledge of environmental protection

from sources of oil contamination. Based on the presented experiences we hope to be able to

identify the best remediation methods and keep us updated on the most efficient methods un-

der the special and challenging climate conditions.

What’s special for the Arctic? Several factors play an important role: a unique ecosystem, a

small population density, a very cold climate and a special geology. These factors make the

Arctic more vulnerable, and it is more difficult to perform remediation than in most of the envi-

ronments, in which we normally operate.

In high concentrations oil is poisonous for most organisms, and the low temperatures in the

Arctic reduce the rate of all physical and biological processes related to decomposition such as

dissolution, dispersion, evaporation and biodegradation. In the marine environment the oil can

be accumulated in biota representing food sources for animals and humans.

The Danish Defence has many important tasks in Greenland and the Arctic such as protection

of the territorial integrity, mapping of the seabed and the ice, inspection of fishing vessels,

performing rescue operations etc. The access to the North Eastern Greenland primarily hap-

pens via airports in Mestersvig and Station Nord, which is run by the Defence.

The Ministry of Defence has a strategy for environment and energy for 2016-2020. This strat-

egy focuses also on initiatives to reduce the energy consumption in buildings etc. and to estab-

lish a more eco-friendly energy supply in Greenland.

For a longer period the Danish Defence has had a strong focus on prevention of unwanted im-

pacts on soil and groundwater at the military bases, including training and modernization of

the POL management facilities (POL is the abbreviation of Petroleum; Oil and Lubricants). A

number of inspections and remediations have been carried out to handle the residual contami-

nation from former oil spills at the military bases. However, a number of oil contaminations

and other environmental challenges still remain.


3. Landfarming

Landfarming - Theory and practice. An example from Northeast Greenland.

Design, operation, monitoring program, results – by Peter Henriksen, NIRAS

Microbial oil degradation in Arctic soil – by Anders R. Johnsen, GEUS

Results from oil and “fingerprinting” analysis – by Jan H. Christensen, Copenhagen University

3.1 The practical implementation

3.1.1 Background and objective

We have conducted a pilot project with landfarming in Mestersvig, North East Greenland. The

background was an oil contamination in the soil detected at the power station with oil of the

type Arctic Grade C – a petroleum-like diesel oil. The contamination was assessed to pose a

risk for a nearby lake and the local birdlife at the lake.

Mestersvig is an airport with a gravel runway, which is primarily used during summer, where

app. 1 plane per week is landing. The station is situated in the National Park in a river delta

leading water from the river and Mestersvig into Noret and from there into the sea.

The climate in Mestersvig is close to Arctic desert with an annual precipitation of app. 300 mm.

The average temperature is only above 5oC for 2 months per year (July and August). The av-

erage temperature in August, which is the warmest month of the year, is about 10oC. The ac-

tive soil layer is app. 2 meters thick.

We performed an immediate remediation by laying out oil absorbing “sausages” in a ditch.

Various potential remediation methods were assessed. Subsequently feasibility studies were

initiated for treatment of the oil-polluted soil by landfarming. We conducted laboratory tests

for determination of the optimal amount of fertilizer. The design was made according to the

following demands:

The plant must be self-draining, but must secure sufficient moisture in the soil.

It must be resistant against frost.

It must be capable of being operated with one annual operating period.

The pilot test must run over 5 years.

No remedial target has been determined – a sub-purpose of the pilot test is to clarify

how low concentrations can be achieved by the method.

3.1.2 Method

The landfarming method entails adding fertilizer to the excavated soil in order to stimulate the

naturally occurring bacteria, so that the oil in the soil can be microbially degraded. Apart from

bioremediation the oil is also removed by evaporation and chemical degradation during the

excavation and the subsequent treatment by landfarming. The focus of this speech is the bio-

degradation.

By landfarming the oil-polluted soil is excavated at the power station (app. 3,000 m3) and a

plant is established, where the stimulated degradation can take place under controlled condi-

tions.

The landfarming site in Mestersvig is 14,000 m2 (160 m x 90 m). The landfarm is constructed

with a frost and oil resistant High Density Poly Ethylene Liner (HDPE) of 1.5 mm with geotex-

tiles on each side at the bottom. Above this there is a protection layer of 0.3 m consisting of

sieved sand. The polluted soil is laid out upon the protection layer. The construction prevents


contact with the underlying soil and enables collection of percolate (leaking water) from the

polluted soil. The construction also ensures that moisture from the protection layer can evapo-

rate into the polluted soil during drought periods securing sufficient moisture in the soil for the

bioremediation.

The plant in Mestersvig is constructed with the landfarm, two downstream basins (basin 1 and

basin 2) from which the water is conducted into Noret through a channel. Between the land-

farm and basin 1 a sluice gate has been established to retain the water in the protection layer.

The total water capacity is 1,250 m3 in the protection layer, 2,250 m3 in basin 1 and 400 m3 in

basin 2, corresponding to a total of app. ½ year’s precipitation. The basins are established in

order to secure control with the percolate from the landfarm, which can contain elevated con-

tents of oil compounds and nitrogen from the fertilizer.

The plant operation is conducted by adding 3 types of fertilizer, which are ploughed down me-

chanically in the polluted soil in early August, when the landfarm is accessible to machinery. 2

slow-releasing fertilizers are added to secure that there is sufficient fertilizer available

throughout the summer period, and a fertilizer, which is immediately soluble. After ploughing

the site is watered, so that the fast-soluble fertilizer is immediately accessible for the bacteria.

Monitoring through sampling of soil and water is performed for adjustment of operation and

assessment of the effect of the landfarming. In addition weather conditions and precipitation

are monitored via weather station and by measurement of the water level, soil temperature

and humidity. Soil samples from the landfarm are taken using a MIS method (Multi Incre-

mental Sampling), providing representative samples covering the whole soil volume in the

landfarm and securing a high degree of reproducibility in the sampling thus securing reliable

results. Soil samples are collected once a year in early August before adding fertilizer. Water

samples are collected as triplicates at the sluice gate, from both basins (3 locations in each)

and at 3 locations in the channel leading the water into Noret. Water samples are collected 3

times during the operation period; mid-July (thaw), mid-August and end-of-August. The water

in the protection layer is also sampled 3 times during the 5 years of operation.

3.1.3 Results

The landfarming plant was established during the summer seasons of 2011 and 2012 and has

been in operation through 2016. The total oil content in the soil at the landfarm has decreased

from 40 tons, before it was excavated and removed, to 3 tons in 2017. In connection with the

excavation and removal of the soil there was a considerable decrease, primarily due to evapo-

ration in connection with the physical handling of the soil. During the operation period of the

landfarm the oil concentration in the soil has decreased – most in the beginning and subse-

quently more slowly. The concentration level at the latest measurement in 2017 was at 585

mg total hydrocarbons (THC)/kg.

Looking at the oil composition over time the C10-C15 fraction dominates both in 2012 (start-

up) and 2017 (latest sampling), but there is a significant reduction. The light fraction (C6-C10)

is almost completely reduced, probably by evaporation during establishment and ploughing.

The heavier fractions (C15-C20 and C20-C35) form a smaller part of the oil contents and are

only slightly reduced, as these fractions are both less volatile and less degradable.

The highest concentrations of total hydrocarbons are seen in the protection layer, whereas a

large reduction is seen throughout the system from the landfarm to the channel over the entire

operation and monitoring period. The largest reduction appears from the landfarm to the sluice

gate, after which the concentrations decrease further out through the basins and the channel.

In 2017 133 µg/l of total hydrocarbons (THC) was measured in basin 1. A worst case flux for

2017 to Noret is calculated at 0, 65 kg of total hydrocarbons. The flux calculation is assessed


to be conservative (over-estimated), as all the precipitation is included and hence the part of

the precipitation, which will evaporate or run off via the surface, has not been deducted.

In 2015 and 2016 a sudden increase in the concentration of total hydrocarbons occurred in

basin 2. This was caused by an algal bloom and was especially remarkable in 2016 due to an

exceptionally warm summer. Commercial analyses of total hydrocarbons cannot distinguish

between oil components and naturally occurring hydrocarbons derived from fatty acids in the

cells of the algae. The increased concentration of total hydrocarbons in the basins is hence not

due to oil, but rather to the algal bloom.

The concentrations of nitrogen in the water in the protection layer below the landfarm are ex-

pectedly high due to the supply of fertilizer. The concentrations drop significantly throughout

the two basins and the channel. A worst case flux to Noret for 2017 has been calculated at 79

kg of nitrogen. This corresponds to the discharge from 19 persons. The flux calculation is per-

formed conservatively in the same way as for the oil discharge.

3.1.4 Conclusion

Landfarming is an efficient low technology method of cleaning up oil contaminated soil under

arctic conditions. The primary removal mechanisms are microbial degradation and evaporation.

In the period of 2012-2017 a reduction of the oil contents in the soil of 82-94% has been

achieved in spite of a very short season of only 2 months with temperatures above 5oC.

Increased levels of oil components and nitrogen in the surplus water (percolate) from the land-

farm were significantly reduced (90-94%) by "self-purification" in the two basins downstream

of the landfarm.

A control field was only fertilized in 2012 and 2013, but the degradation continued subse-

quently. This indicates a potential for continued degradation in the landfarm, although the fer-

tilization has stopped.

3.2 Microbial oil degradation in arctic soil


Landfarming is based on evaporation of the light oils and biodegradation of the remaining oil

components, mainly by complete mineralization to carbon dioxide and water. The two control-

ling factors for the degradation are temperature and nutrients.

In order to study the influence of these two factors on microbial conditions in the Arctic we

started by performing laboratory tests with soil from Station Nord.

The soil at Station Nord does not contain any organic substances, and the microorganisms are

not particularly active. There is permafrost from 1 m below ground. Spill of jet fuel will perco-

late down through the top 1 meter of soil and settle on top of the permafrost or maybe dis-

perse horizontally at that depth.

Tests with the 14C-marked jet fuel have been performed at 5oC with addition of fertilizer in dif-

ferent concentrations (N.P.K. in the ratio of 15:5:14). The results show that supply of fertilizer

in even small concentrations results in a significantly increased degradation and that too high

concentrations of fertilizer inhibit the bacteria so that the decomposition can stop completely.

The results also show that salt at too high concentrations can inhibit the degradation.

Furthermore, degradation tests were carried out under different temperatures (-5oC, 0oC,

+5oC, +10oC). At -5oC no degradation was seen. At +5oC and +10oC an increased degradation


was observed. At 0oC degradation occurs, however with a prolonged adaptation period. A mi-

crobial degradation is thus in progress as long as the temperature is at or above 0oC.

In connection with the landfarming project in Mestersvig, laboratory analyses of soil from the

landfarm have been carried out to determine whether there are naturally oil-degrading bacte-

ria present in the soil, whether the naturally occurring bacteria can be stimulated and whether

there are degraders for all oils present.

3.2.2 Method

Soil and water samples from the landfarm in Mestersvig from every year in the period 2012-

2017 have been analysed for various specific degraders (bacteria) using the MPN (Most Prob-

able Number) method. The objective is to investigate the microbial composition of various oil-

degrading bacteria over time in the landfarm.

3.2.3 Results

Analyses show that there is a very large microbial population of degraders (number of bacte-

ria) in the landfarm – on a par with similar sites in Denmark. There is also a large metabolic

diversity, so that degraders have been found both for the more readily degradable compounds

and for the more recalcitrant compounds. This shows that the degradation proceeds com-

pletely (to carbon dioxide and water) for also a part of the complex oil compounds. For the

very complex oil compounds, no degraders have been found - this will be the same under Dan-

ish / temperate conditions.

When the concentrations of total hydrocarbons (all oil compounds) decrease, and only reduced

slowly, the very heavy and complex oil compounds remain.

The results from soil and water samples taken at various places at the plant show that in the

untreated soil there is very little microbial activity, whereas there is a very high microbial ac-

tivity (degradation) in the landfarm. The number of bacteria is very low in the two basins,

probably due to washout.

3.2.4 Conclusion

Supply of fertilizer in even small concentrations gives a significantly increased degradation, but

too high concentrations of fertilizer inhibits the bacteria so that the degradation can stop com-

pletely. Microbial degradation occurs as long as the temperature is at or above 0oC.

Oil-degrading bacteria occur naturally in Arctic soil. By addition of fertilizer the microbial activ-

ity is stimulated and the number of bacteria is increased by more than a 1000 fold.

The naturally occurring bacteria can grow on a wide variety of different oil compounds. Some

of the more heavily degradable aromatic hydrocarbons can also be degraded. However, some

of the very heavy and complex oil compounds are limited to co-metabolic degradation.

3.3 Chemical fingerprints in oil analyses


Oil is usually analysed with commercial analyses of total hydrocarbons divided in fractions and

with specific analyses of the PAH’s, for which guideline values have been stipulated. However,

oil is an incredibly complex mixture of over 100,000 different individual compunds. The most

readily degradable substances are not necessarily the most toxic substances. Overall oil com-

punds can be grouped into:


Alkanes – non-toxic, food for bacteria

Multi-chain alkanes, such as naphthalene – a little harder to degrade and a little more

toxic

Aromatics (e.g. PAHs) – difficult to degrade, toxic

Other hydrocarbons (e.g. asphaltenes, NSO compounds)

Organometallic compounds

The typical division in fractions:

C6-C10: Easily degradable

C10-C25: Complex mixture. By degradation an increase is often seen in this fraction

due to formation of degradation products

C25-C35: Including PAHs. Often the PAHs included in the standard analysis (and for

which guideline values are stipulated) do not occur in oil, but other PAHs occur. These

are typically not included in the analysis.

By degradation where no mineralization to carbon dioxide and water occurs, degradation prod-

ucts are formed, which are often more water-soluble, i.e. more mobile.

The measured removal of e.g. PAHs from the landfarm does not distinguish between physical

and biological removal mechanisms.

3.3.2 Method

Samples from the landfarm in Mestersvig are analysed using the “fingerprinting” method. The

method involves an assessment of removal and degradation of more than 500 oil compounds

in the landfarm. This includes a quantitative removal of alkanes and alkylated PAHs as well as

a distinction between physical removal processes (evaporation and washout) and biodegrada-

tion.

Furthermore, a verification of the biodegradation by analysing specific degradation indicators

(metabolites) was made. For some compounds found as various isomers bacteria have a pref-

erence for one of the isomers. By analysis of the specific isomers and the development in the

ratio between the isomers it can be verified whether a biodegradation of the mother compound

actually occurs.

Analyses are also made of metabolites (typically aromatic acids). A single oil compound can

form between 5 and 30 metabolites.

Focus for these analyses from Mestersvig has primarily been on PAH removal.

3.3.3 Results

Results show that 94-98% of the di-aromatic compounds (naphthalenes) have been removed

by evaporation in connection with establishment of the landfarm. Subsequently a further de-

crease in concentrations occurred in the period of 2012-2017. The removal mechanism in this

period cannot be distinguished solely based on the concentrations.

The results from the degradation indicators show that the isomer ratio decreases in the period

2012-2017, which shows that a degradation of these substances actually happens. This counts

for aliphates and 2-2½ ring aromatic compounds, whereas the results are not as unambiguous

for the 3-ring aromatic compounds.

The results from the fingerprinting analyses (shown as 3D chromatograms) show that during

the period a wide range of degradation products are formed, which proves that microbial deg-

radation is occurring in the landfarm.


3.3.4 Conclusion

90-100% of the most volatile mono and diaromatic hydrocarbons has been removed before

and during establishment of the landfarm. An almost complete removal of alkanes and C1-C1-

akylated di-aromatic compounds has taken place in the landfarm in the period 2012-2014.

Removal of the more recalcitrant and potentially toxic alkylated 3-ring PAHs and sulphurous

aromatic compounds occurs from 2015 and onwards.

Indicator conditions for biodegradation show that biodegradation and not only evaporation oc-

curs in the landfarm. Very complex mixtures of aromatic acids have been detected in the per-

colate from the landfarm, which is a strong verification of the occurrence of biodegradation.

Only very low (µg/l) concentrations of aromatic acids have been detected in the basins.

Chemical fingerprinting data in combination with quantification of oil-degrading bacteria and

detection of degradation products have conveyed to a strong knowledge of the ongoing bio-

degradation in the landfarm and of biogenic contents in the total hydrocarbon analysis.

3.4 Discussion (Q&A)

Q: Has the toxicity been analysed before and after the landfarm?

A: No. This was not part of the project. If so, you should determine, where you want to meas-

ure (soil, water, location?).

Q: What is the cost of project? A: 35 million DKK

Q: By forming soluble and potentially more toxic degradation products you could risk creating

a larger/more toxic problem by landfarming?

A: This is an important research question. You achieve lower concentrations, but a more com-

plex number of compounds. It is important to document complete mineralization.

Q: Could you import bacterial cultures?

A: That is not necessary – the naturally occurring bacterial culture is diverse and can be stimu-

lated.

Q: Have you measured the oxygen contents in the soil?

A: No, only in the water.


4. Bioremediation

Bioremediation of Petroleum Hydrocarbons in the Canadian Arctic.

By David Juck, National Research Council, Canada

4.1 Background and objective

Introduction to working under arctic conditions:

The treatment period is limited, where the temperature is above 0oC; app. 8-12 weeks

(June-August). In Alert the average temperature during the warmest month (July) is

3.3 oC.

The sites are located in arctic desert. In Alert the annual precipitation is 154 mm.

There is no groundwater.

Contaminant spreading occurs horizontally during spring by thaw.

Infrastructure (buildings) is founded directly in the permafrost, i.e. there is risk of sub-

sidence damage by excavation close to buildings.

Logistical limitations by means of limited infrastructure at the stations, limited access

for heavy machinery, local manning has limited experience with remediation, freight of

materials to the stations can take up to 2 years.

Big rotation of employees at the stations and inadequate written documentation of ac-

tivities through time, i.e. the total historic knowledge of activities and installations is

limited.

Examples are shown from 2 sites in northern Canada: Eureka, where an in situ biopile was

established and Alert, where an ex situ biopile and an in situ bio-barrier were installed.

4.1.1 Eureka High Arctic Weather Station

Spill of 37,000 litres of diesel oil posing a risk to a neighbouring reservoir, which is the drinking

water supply of the station. App. 3,200 m3 of soil is contaminated.

4.1.2 Alert

Two spills of fresh diesel oil have occurred at the Alert station; one in 2005 and one in 2006.

Additionally an oil contamination from a 12 year old spill was detected. Here the composition

of oils can prove more recalcitrant.

Initially laboratory tests were made with soil from the fresh spill in order to determine the op-

timal fertilizer type for stimulation of the bacterial degradation. MAP (Mono-Ammonium-

Phosphate) was chosen. Based on this a minor biopile was built in 2005 and subsequently a

larger biopile plant was built in 2007 in order to treat excavated diesel-polluted soil from both

fresh spills (total of 2,500 m3 soil).

In 2011 biopiles for treatment of the older oil spill (total of 100 m3 soil) were established in a

separate area within the same biopile plant.

At the Alert station further spills had occurred, where the contamination has spread in the di-

rection of vulnerable water recipients. To protect the recipients a bio barrier perpendicular to

the flow direction was installed.


4.2 Method

4.2.1 Eureka – In Situ Biopile

The oil-polluted soil was treated where the spill occurred, i.e. it was not removed. An annual

treatment was carried out consisting of supply of fertilizer (NPK in the ratio of 15:3:2) and wa-

tering, after which the top 40 cm of the soil was mechanically reversed (with engine power).

Since year 2000 annual samples have been taken for chemical, microbial and molecular bio-

logical analysis. The analyses with Functional Gene Microarray were carried out in the years

2002-2002 and in 2004.

4.2.2 Alert – Ex situ biopile

The biopile plant was established on a sand foundation with geotextile, impermeable mem-

brane and a protective sand layer as well as berms of app. 2 meters around the whole biopile

site. The contaminated soil was laid out in windrows. Once a year since 2007 the soil has been

reversed with an excavator and fertilizer is added (MAP). No leachate collection system has

been established, as there is water shortage due to desert conditions and hence a need to

keep all the water in the biopile plant. A control-pile without fertilizer-supply (MAP) was estab-

lished.

The method is thus similar to landfarming with the difference that the soil by landfarming is

evenly dispersed over the whole site, whereas biopiles are laid out in windrows (comment from

reporter).

In order to investigate which removal mechanisms are active in the reduction of the oil con-

centration metagenomic analyses have been performed in order to study the occurrence of

microorganisms and analyses of stable 15N-isotopes (15N Stable Isotope Probing) have been

performed to prove that biodegradation of oil compounds actually takes place.

4.2.3 Alert – Bio barrier

The design of the bio barrier is based on the good experiences gained with the biopile with

MAP-addition (fertilizer). The idea is to establish a in situ mini-bioreactor, so that the oil com-

pounds in the water running through the barrier are degraded in the barrier. The bio barrier

was established in July 2017. A ditch of app. 1 meter’s depth and 26.5 meters’ length was ex-

cavated. The bottom was covered with geotextile. A piping system for supply of fertilizer and

ventilation and for collection of leachate above the permafrost was installed in this ditch. The

fertilizer (MAP) was placed as pellets in the pipes along the bottom of the ditch. Oxygen was

supplied via ventilation pipes attached to wind turbines app. 2.2 m above ground creating a

vacuum and hence drawing fresh air into the barrier.

A longitudinal transect for monitoring was established across the barrier with monitoring points

upstream, in and downstream of the barrier.

4.3 Results

4.3.1 Eureka – In Situ Biopile

Soil concentrations of total oil compounds have been reduced during the 7 years of operation

with app. 85% in the active layer from app. 10,000 mg/kg to app. 1,000 mg/kg, i.e. below

their criteria of 2,500 mg/kg. There has also been a reduction of app. 60% in the permafrost

layer (unknown to which depth, Ed.)


The results of the microbiological analyses show that there is a large number of bacteria pre-

sent in the biopile and a stimulation of the bacteria occurred during the treatment, as the

number of bacteria is app. 10 times higher than in the control field. Furthermore the results

show that the composition of bacteria is dynamic and changes over time concurrently with the

oil being degraded. All bacteria are naturally occurring bacteria, adapted to the Arctic condi-

tions.

4.3.2 Alert – Ex situ biopile

Results for naphthalene and hexadecane for 2008 and 2010 show that the degree of minerali-

zation (the degradation) increases during the field season and that it was higher in 2010 than

in 2008, the year after the establishment of the plant.

Results for total concentrations of the fraction C10-C16 in the ”fresh spill” soil during the pe-

riod 2007-2015 show that the concentrations have dropped by app. one order of magnitude in

the biopile, whereas the reduction in the control field is much smaller. The average concentra-

tion in the biopile was 112 mg/kg in 2015 for the C10-C16 fraction, which is below the criteria

of 260 mg/kg.

Results for the total concentrations of the C10-C16 fraction in the aged spill-soil in the period

2011-2015 also show a decrease by app. one order of magnitude in the biopile – an average

from app. 2,000 mg/kg to app. 200 mg/kg. The soil hence reacts very quickly to the treat-

ment.

The treated soil will be removed from the biopile plant so that soil from other oil spills can be

treated there.

The metagenomics analyses of the bacterial population show that the bacterial composition is

very dynamic . Thus the bacterial composition changes over time due to the changed composi-

tion of oil compounds.

The 15N-isotope analyses show an increase in the isotope ratio 15N/14N in the DNA of the de-

graders, which shows that the required bacteria are present and that they are active.

4.3.3 Alert – Bio barrier

Results from the operation of the bio barrier are not yet available, but naturally occurring ac-

tive degraders of alkanes and aromatic compounds have been detected.

4.4 Conclusion

Bioremediation is a viable remedial method under Arctic conditions. A simple ”passive” biopile

plant is efficient for remediation of both fresh and aged oil contamination. It is important not

to overdose the fertilizer, as high concentrations of fertilizers can inhibit the bioremediation.

More frequent supply of low-concentrated fertilizer dozes is optimal for the bacteria. Very ac-

tive naturally occurring microorganisms are detected under Arctic conditions.


Q: Have you any data for the heavy oil compounds?

A: We have no significant concentrations of the heavy oil fractions (F3)

Q: Do you have sulphurous aromatic compounds?

A: We have not performed very detailed chemical analyses (fingerprinting or so, as it wasn’t

included in the objective and budget)


Q: What is the planned frequency for monitoring of the bio barrier?

A: Annual sampling is scheduled

Q: What is the radius of influence of the ventilation wells in the bio barrier?

A: There is very little influence in the permafrost. A gravel layer has been installed in the bar-

rier to increase oxygenation. It is planned to install similar bio barriers at other sites.

Q: How thick is the membrane in the biopile?

A: Cannot remember the precise thickness

Q: What is the aim of the clean-up?

A: The state clean-up criteria are 260 mg/kg for the fraction F2 (C10-C16, Ed.). At some sites

metal contamination is also a problem. Typically, the overall guidelines/clean-up criteria are

set as remedial objectives, but it is possible to establish site-specific clean-up criteria under

special conditions, such as at sites with a natural high background content of arsenic, the

clean-up criteria may be elevated.

At Alert different types of toxicity tests has been performed and no toxicity effects have been

detected.

Q: Which toxicity test has been used?

A: E.g. Microtex and earth-worm-test.


5. Overview of remediation techniques in Antarctica

An Overview of Hydrocarbon Remediation Techniques and Activities Conducted at Australian

Antarctic Stations.

By Tim Spedding, Australia Antarctic Division, Environmental Risk & Remediation Team


The Australian Antarctic Division is responsible for research/science, operation and logistics as

well as strategies and guidelines. They operate at 4 Australian stations: Casey, Davis, Mawson

and Macquarie Island (Macquarie Island is an island situated between Antarctica and New Zea-

land). Less than 0.5% of Antarctic is ice-free. Most of the stations and most infrastructure are

located in these areas and in these areas the risk of impact of human activity is greatest.

There is no ownership of Antarctica. Commitments to perform remedial actions in Antarctica

are based on the Madrid 1991 Protocol "PROTOCOL ON ENVIRONMENTAL PROTECTION TO

ANTARCTICA TREATY, ANNEX III: WASTE DISPOSAL AND WASTE MANAGEMENT". They em-

phasize that risk is assessed both for leaving pollution behind and by remedial action - they

operate from a more holistic approach, where the overall environmental impact is assessed

and optimized.

Australian Antarctic Division has an ongoing collaboration with e.g. Melbourne University, Uni-

versity of New South Wales and Queens University (Canada).

Contamination in Antarctica typically includes old waste (in waste dumps and on the seabed),

oil/fuel spills and wastewater discharge. The logistical constraints in Antarctica are very similar

to the ones in the Arctic. There is very little organic matter in the ground. It is not permitted to

bring non-native animal species or bacteria to Antarctica, who do not occur naturally in Antarc-

tica. If soil is imported from areas outside of Antarctica, this soil must be sterilized prior to

import. The permafrost and freeze/thaw cycles result in a special catchment area hydrology.

5.1.1 Casey

In September 1999 (winter) there was an oil spill of 8,000-10,000 l fuel oil (mixture of 75%

Bergen and 25% ATK). In order to prevent spreading of oil contaminated meltwater to down-

stream recipients a Permeable Reactive Barrier (PRB) was installed.

5.2 Method

5.2.1 Casey – Reactive barrier

The reactive barrier is constructed using activated carbon (GAC), which adsorbs the oil com-

pounds, when they pass the barrier, slow-releasing fertilizer, which continuously releases nu-

trients to stimulate the biological degradation, and zeolites, which remove surplus nutrients

before the water runs out through the barrier. The design was based on a minimal energy con-

sumption and as limited infrastructure as possible and that the solution must be cost-effective.

The barrier can treat a mixture of polar and non-polar contaminants, e.g. oil, solvents, PCBs

and heavy metals.

By establishment of the barrier it is important to secure meticulous drainage, as otherwise it

will freeze in the winter. To further prevent freezing heat threads are installed in the barrier.

The barrier was excavated and re-established in 2010. Experiences from the period 1999-2010

include that fine particles are transported into the barrier, reducing permeability over time.


5.2.2 Casey - Biopiles

At the Casey station biopiles have also been used to treat excavated, oil-polluted soil. At the

installation an impermeable barrier is laid out under the biopiles and infrastructure is installed

directly in the soil for nutrient supply (fertilizers) and to aerate the soil to stimulate the oil

degradation.

5.3 Results

5.3.1 Casey - Reactive barrier

No results are shown from the active barrier, as it is installed in the summer of 2017.

5.3.2 Casey - Biopiles

A reduction of the total oil content occurs over 5 years of operation from app. 3,500 mg/kg to

app. 500 mg/kg.

5.4 Conclusion

The overall remediation strategy in Antarctica includes:

Encapsulation (such as Permeable Reactive Barrier)

Biopiles

Study and washing of coarse-grained materials (stones, blocks) and further ”polishing”

prior to recycling.


There was no discussion following the speech.


6. Biopiles in Antarctica

Building and Operating Biopiles to Remediate Fuel Contaminated Soil in Antarctica.

By Rebecca McWatters, Australia Antarctic Division


Introduction by Tim Spedding (previous speech).

6.2 Method

After the oil spill at the Casey station in 1999 the reactive barrier was installed (see Tim Sped-

ding’s speech). However, the oil pollution was not reduced significantly at the spill location. A

more aggressive action was necessary. Hence, in 2012 the soil was excavated, and 8-9 bio-

piles were established.

Biopiles are based on using naturally occurring bacteria for degradation of oil contaminated

soil. The degradation is stimulated by adding oxygen and perhaps fertilizer. It is not allowed to

use bacteria or other substances which are not naturally occurring on the site.

The membrane under the biopile plant is a composite membrane and consists of a geosyn-

thetic clay membrane (GCL), a geomembrane, geotextile and a protection layer (soil). The

membrane is also aimed at separating the contaminated soil from the surrounding environ-

ment.

2 layers of geotextile are laid out over the biopiles as cover. This is done to retain the water,

as Casey is situated in a very arid area. The cover is regularly replaced, as it is decomposed by

the harsh weather conditions.

Berms are established around the biopile plant.

There is very little soil available at Antarctica, and hence much is done to treat the soil in order

to reuse it for other purposes after clean-up.

6.3 Results

6.3.1 Experience with establishment of biopiles

Challenges with installation and design:

The soil at Casey is very coarse-grained. Fine-grained material is important, as it re-

tains the moisture.

During summer a massive water pulse occurs in connection with thaw. It is important to

divert the water away from the biopile plant to prevent the water from entering the

biopiles or undermine the area underneath.

The lowest layer of the membrane is a GCL (geosynthetic clay membrane). It is impor-

tant to keep the bentonite clay in the membrane hydrated as otherwise it will dry up

and cause leakages, through which leachate can migrate. The clay is kept moist, if

there is a heavy weight on top. At the edge of the piles the weight is less heavy, and

the risk of desiccation is thus higher.

The cover layer of geotextile is permeable. If you use impermeable materials (plastic or

geomembrane), it will be destroyed very quickly by the heavy winds.


They use black cover materials to increase the temperature as much as possible in the

piles. They do not want to heat the soil to avoid using unnecessary fuel for the clean-

up.

Experience with operation of biopile plants:

They turn the soil in the piles mechanically once a year

Aeration systems: initially they had installed a ventilation system in the piles to add

oxygen. This didn’t work. In future biopiles ventilation systems will not be installed.

Drainage system: For optimal operation leachate is recycled 3 times a week during the

season. It is important to keep the soil moist to increase the biodegradation activity.

Fertilizer: Initially they added fertilizer as pellets (dry). Based on their experience it

would be better to add fertilizer as liquid. It is important not to add too much fertilizer.

One portion of fertilizer should be sufficient.

6.3.2 Results from operation of biopiles

Looking at the degradation as a function of days where the temperature is above 0oC, the

highest degradation rates are seen in the beginning, shortly after establishment of the biopile

plant.

The removal processes before the excavation were bioremediation (slow) and no evaporation,

whereas during the excavation and during the biopile treatment both biodegradation and

evaporation were important removal mechanisms.

The conclusions on microbial conditions are similar to the conclusions from the Mestersvig pro-

ject.

6.4 Conclusion

The research team at Antarctica has gained experience with: clean-up of oil spills, excavation

of polluted soil and establishment and operation of biopiles and of barrier systems under bio-

piles.

They continue working with methods to accelerate the biodegradation. One example is bio cells

consisting of minor soil volumes that are water-saturated and where the conditions can be

controlled more directly. One of the test methods is to add surfactants. Another method con-

sidered is electrokinetic oxidation in the biopiles above ground.

Furthermore they continue working with stipulation of remediation criteria and guidelines for

reuse of soil, ecotoxicology and costs, technical challenges and politics.

She asks, why remediation criteria in Scandinavia (Sweden/Norway) are so much lower than in

other countries such as in Canada.


Q: Why have they stopped measuring the oxygen level in the soil?

A: Because the results didn’t provide any valuable information

Q: Concerning the bentonite membrane – are non-native bacteria introduced?

A: According to normal practice all soil imported to Antarctica is sterilized. In this particular

clay soil there was entirely sulfate-reducing bacteria.

Q: Regarding reuse of soil – what are the plans of the Mestersvig project for potential reuse of

the soil?

A: One of the next steps of the project is to conduct a risk assessment for reuse of the soil,

including assessment of the potential future applications of the soil.



7. In situ remediation in North Sweden

Case studies of Successful In situ Treatment of Oil Contamination under Arctic Conditions

By Jonny Bergman, RGS Nordic, Sweden.


The three sites are located in Northern Sweden. There is no permafrost, but frost down to 2-

2.5 meters depth. The Arctic conditions slow down the biological and chemical reactions and

involve large costs for heating above-ground installations and for operation e.g. due to icing.

The frozen soil form a “lid”, which causes slow infiltration of surface spill and provides a good

protection against vapour intrusion into buildings.

7.1.1 Vittangi petrol station

Oil spill due to leaking fuel pipe because of ground movements due to frost. The aim of reme-

diation is primarily to stop the oil migration and to remove free phase oil. The oil pollution cov-

ers app. 1,200 m2 from 0-5 meters depth. The many installations and tanks at a petrol station

pose a challenge to remediation.

7.1.2 Piteå fuel depot

App. 16,000 tons of oil-polluted soil with concentrations of more than 10,000 mg/kg total hy-

drocarbons have been excavated. At a harbour close by soil for filling of the harbour site is

required.

7.1.3 Stöde trucks filling station

The site is a closed diesel tank station. The oil pollution covers app. 1,000 m2 from 0-3 meters

depth.

7.2 Method


MPE (multiphase-extraction) has been deployed for removal of free phase oil and AS (air

sparging) and SVE (soil vapour extraction) have been used for removal of dissolved oil com-

pounds . The methods are chosen to secure a rapid remediation, which can be carried out dur-

ing a single summer season. The top soil layer has been excavated to identify locations of

pipes and tanks and for identification of the leaking pipe.


The oil-polluted soil is treated in biopiles ventilated with heated air and amended with fertilizer.

Estimated remediation time: 2 years.

7.2.3 Stöde truck filling station

The shallow source area was excavated (500 tons soil). The deeper contamination was treated

with

Soil flushing and ISCO (chemical oxidation) under the building

Biosparging with nutrient supply (NP in the ratio 10:1 to 100C).


Initially we conducted a pilot test to estimate the volume of injection. We performed monitor-

ing of the groundwater and soil gas as well as of the indoor air of the building.

7.3 Results


Within one year the free phase in the monitoring wells was removed. The dissolved concentra-

tions are still rather high.

The free phase has been removed and concentrations are below 30% of the solubility, which

means that the mobility of the remaining oil pollution has been reduced. The remediation level

has been approved by the authorities.

25 m3 of oil has been removed and destructed. App. 7 m3 of oil has been treated with catalytic

oxidation. A total of 30-35 m3 of oil has been removed in one year.


The oil contamination has been totally remediated in 1½ years to below the determined crite-

ria.

Biopiles are recommended for sites with a large distance to treatment facilities, where there is

enough space and where the treated soil can be reused. This is a simple and robust method. It

helps to heat the soil, as it speeds up the biological processes.

7.3.3 Stöde truck filling station

The remediation has been going on for 1½ years. Degradation rates for biosparging has been

calculated from the produced carbon dioxide. Concluding groundwater concentrations were

below the remediation goal (not indicated, ed.), some below the detection limit. Significant

reduction of concentrations were seen in the course of the first 6 months, after which the con-

centrations have stayed at the same level.

In connection with soil flushing 600 m3 of water were treated and recirculated, equivalent to

app. 9 porewater volumes. Surface-active compounds and chemical oxidants were added dur-

ing 3 events. The groundwater concentrations after the remediation were below the detection

limit.

7.4 Conclusion

Remediation under Arctic conditions calls for finding practical solutions. Use risk-based reme-

diation criteria. Sometimes it is more practical to close down the remediation during the cold

periods. Use of some energy for heating can be rewarding in terms of a shorter remediation

period. Remote monitoring can save costs.




8. Electrokinetic remediation

Potential of Electrokinetic Remediation of Oil Contaminated Soils.

By Lisbeth M. Ottosen, DTU


Electrokinetic processes can be used for distribution of reagents in porous media. We haven’t

yet used electrokinetic remediation methods under Arctic conditions. The aim of this speech is

to assess the viability of such methods under Arctic conditions and in that case which to use.

To use EK in Arctic areas, the power supply must be based on green energy (wind, solar).

8.2 Method

The predominant electrokinetic processes are in:

Clay soil: Electromigration (transport of ions) and electroosmosis (transport of pore

fluid) and to a lesser degree electrophoresis (transport of charged particles)

Sandy soil: Electromigration (transport of ions) and electrophoresis (transport of

charged particles) and to a lesser degree electroosmosis (transport of pore fluid).

Electrokinetic transport (EK) can be used in combination with other remediation methods, as

electrokinetics enables transport of reagents into dense sediments such as clay. EK can be

used together with bioremediation (EK-BIO) with chemical oxidation (EK-ISCO and EK-TAP) or

as a method for containment to prevent contamination migration (Fencing).

8.2.1 EK-BIO

EK-BIO for remediation of oil compounds is based on amending an oxidizing agent (e.g. nitrate

or sulfate), which is distributed in the contaminated soil by electrokinetic transportation proc-

esses. According to literature EK-BIO has been tested for oil compounds. The tests showed

that EK-BIO resulted in faster degradation of total hydrocarbons than by using BIO alone or EK

alone.

EK-BIO has been tested in full scale in Denmark on chlorinated solvents with a positive result.

8.2.2 EK-ISCO/EK-TAP

Chemical oxidation of oil compounds can be performed using for example Fenton’s reagent,

peroxide, permanganate and persulfate. Laboratory tests referred to in the literature have

proved that EK combined with chemical oxidation has proven effective for remediation of oil

contaminated soil.

A variation of EK with chemical oxidation is EK-TAP, Electrokinetic Enhanced Thermally Acti-

vated Persulfate. This method aims at distributing the chemical oxidation agent persulfate in

the soil using electrokinetics, and that the same electrodes subsequently are used for heating

of the soil to activate persulfate, so that the contamination can be decomposed by oxidation

(by changing the power from direct current to alternating current). Quotation from the litera-

ture indicates that persulfate oxidation (with iron-activation) is able to treat soil contaminated

with diesel and fuel oil.


8.2.3 Suspended EK

Excavated soil can be treated ex situ with electrokinetic remediation. Laboratory tests reported

in the literature show degradation of oil compounds in soil from Arctic sites. Laboratory tests

with soil from Sisimiut, Greenland, showed removal of heavy metals, TBT and PCB of more

than 40% and less than 35% removal of PAHs.

8.2.4 EK in Grønnedal?

The coarse-grained soil in Grønnedal does not speak for the use of EK-BIO or EK-TAP. A possi-

bility to use EK in Grønnedal could be to establish an EK barrier along the coastline to fence

the contamination from migrating to the sea. Using an EK fence will enable catching polar pol-

lutants flowing through the barrier. Also nutrient amendment and oxidation can be applied in

the EK barrier. If the source area itself is not remediated, a barrier solution must be run for as

long time as the contamination is still present and poses a threat to the downstream recipi-

ents.

8.3 Conclusion

For Arctic conditions the potential EK methods could be:

EK-TAP for oil remediation in cold areas

Suspended EK for remediation of sediments with mixted contaminants

EK-barrier for containment of contamination in Grønnedal

There is still a number of knowledge gaps regarding the EK techniques to be clarified through

tests in laboratories and in the field.


Q: How much power do the methods need?

A: They aren’t very power-consuming, and we use low voltage direct current, which isn’t dan-

gerous. EK-BIO remediation in Denmark used app. 25% of a typical power consumption for a

thermal remediation of the same volume.

Q: Can the bacteria survive the electrical field?

A: Literature shows that they can

Q: How large a temperature rise is necessary to activate in EK-TAP?

A: To app. 30-40oC.


9. Chemical oxidation

Effective Remediation of Petroleum Hydrocarbons in Water-Borne Deposits at Grønnedal Using

Chemical Oxidation.

By Jarl Dall-Jepsen, COWI


Grønnedal in situated in Southwestern Greenland facing the Arsuk Fiord. Oil contamination has

been detected app. at 32 locations with contamination in the unsaturated zone and at 4 loca-

tions with oil contamination in the saturated zone (below groundwater level). The speech pre-

sents a pilot test carried out in Grønnedal to test chemical oxidation for remediation of oil con-

tamination in the saturated zone.

The challenges in Grønnedal are, among other things, that the terrain slopes steeply down to

Arsuk Fiord and the fact that contaminated areas are close to the fiord with a tidal water im-

pact of app. 2 meters. The geology consists of 5 meters of glacial deposits on top of bedrock.

The glacial sediments consist of coarse materials (sand and gravel). There is a large seasonal

variation in the groundwater level.

The risk assessment shows that due to the dilution there is no unacceptable impact on the

fiord. No free phase oil has been detected in the fiord. The monitoring shows a rather stable

flux of oil compounds to Arsuk Fiord.

Based on a review of potential remedial actions chemical oxidation with hydrogen-peroxide-

activated persulfate is identified as a possible method for remediation of the contamination in

the saturated zone. Pilot tests were carried out in the summer of 2015.

The objective of the pilot test was to determine injection design, assess the remediation effi-

ciency and clarify any secondary effects of the chemical oxidation.

9.2 Method

During 14 to 22 June 2015 we conducted pilot tests at 2 sites (POL and Kraften), both heavily

oil-contaminated sites and situated at a reasonably large distance from the fiord (125 m). We

performed injections and monitoring in existing wells. We injected 20 m3 and 27 m3, respec-

tively, of injection fluid at the two sites. A total of 4,200 kg of persulfate and 8,000 litres of

hydrogen peroxide were injected.

9.3 Results and conclusion

We were able to inject the required amount of persulfate. Indicator parameters indicate that

persulfate has been distributed around the injection wells and has subsequently been con-

sumed. It is assessed that the persulfate is active for 5 days and has not migrated to the fiord.

However, it can be a challenge to treat the contaminated areas located closer to the fiord, as

there can be a risk of spreading of oxidants to the fiord.

It has not been possible to document the effect of the treatment on the contents of oil com-

pounds in the groundwater. Possibly because the soil is heavily contaminated and the pilot test


only treats a small part of the contamination, so that the groundwater is rapidly re-

contaminated.

In spite of this, the speaker assesses that chemical oxidation has a good potential as a reme-

diation method in the saturated zone.


Q: Have they considered photo-induced toxicity? This is a well-known phenomenon in connec-

tion with chemical oxidation?

A: No. The idea is that with chemical oxidation degradation products are not created, but that

a complete mineralization occurs.

Comment: Very likely a complete mineralisation will not occur by chemical oxidation of such

complex compound mixtures as oil. There are many studies in the literature of chemical oxida-

tion of oil compounds – also light fuels and aromatic compounds. These confirm that a com-

plete mineralization does not occur, but that other aromatic compounds are created. It should

be possible to document this by analyses of the composition (fingerprinting) before and after

the treatment, respectively.


10. Thermal remediation

In situ Thermal Treatment in Arctic?

By Kim Jensen, Arkil


Thermal remediation by thermal conductivity, known as ISTD/ESTD (In Situ/Ex Situ Thermal

Desorption) is a well-documented method of remediation of oil contamination and a large

number of other types of contaminations (chlorinated solvents, mercury, tar etc.). The speech

aims at assessing whether thermal remediation is viable under Arctic conditions.

10.2 Method

Thermal remediation is based on the contaminated soil volume being heated up to the tem-

perature, which makes the actual contaminants evaporate. Ventilation wells are also installed

in the soil, which extract the evaporated contaminants from the soil. The heating is conducted

by heater wells, from which the heat is lead through the soil. The heater wells are supplied

either with electricity or via oil/gas burners (“smart burners”). The latter type was presented in

the speech.

By using oil or gas burners for thermal remediation of oil contamination the advantage is that

the oil removed from the soil can be led through the oil burner and be used as an energy

source for the ongoing heating of the soil. The contamination hence contributes to a part of the

fuel consumption of the remediation.

The remediation is conducted in three steps: 1) Heating to the boiling point, 2) the tempera-

ture is maintained at 100oC until all the water has evaporated from the soil, 3) the soil is fur-

ther heated to the required temperature for the actual type of contamination.

At an In Situ remediation (ISTD) wells are installed in the contaminated soil volume. At an Ex

Situ remediation the contaminated soil is excavated and treated according to the same princi-

ples in a closed container. The same plant can treat more soil volumes successively, hence the

plant can be reused.

10.3 Results

Examples of possible implementation of ISTD and ESTD, respectively, are presented by

sketches and photos.

10.4 Conclusion

The following advantages are indicated for the use of ISTD/ESTD in Arctic areas: The equip-

ment is easy to transport in 20 foot containers, the method uses diesel fuel, which is already

used for other purposes in the Arctic, the equipment has only few mobile parts (the ventilation

system) and is hence not so vulnerable to the cold temperatures, the method is suitable for

seasonal operation and has only few spare parts. With thermal remediation it is possible to

clean-up down to very low concentrations.


11. Remediation of fuel oil at lighthouses

Remediation of Fuel Leaks from Remote Lighthouses in Northern Norway.

By Liv Marit, Rambøll Norway


In 2015 an oil spill occurred at Vardø lighthouse on Hornøya in Northern Norway at the Barents

Sea. The oil spill occurred as a leakage from a valve between two underground tanks. High oil

concentrations were detected in the soil.

The lighthouse is situated in a wildlife sanctuary with a bird cliff. The infrastructure is difficult,

as the location is on an island with difficult accessibility for larger boats. Transport to and from

the island is primarily done in small boats or via helicopter. The lighthouse is placed 560 me-

ters above sea level. The weather changes quickly and during winter it is dark.

11.2 Method

The remedial actions are performed in several steps.

Step 1: The tanks have been replaced. New tanks have been flown in by helicopter. The heavi-

est contaminated soil has been excavated and collected in big bags and small containers,

which have been transported away from the island by helicopter for clean-up.

Step 2: Residual contamination has been delineated with borings. An excavator has been

transported to the island to excavate part of the residual contamination. The soil has been

stored in big bags on the island during the summer for the sake of the birds and transported

away from the island in the early autumn together with extracted contaminated groundwater.

The water has been extracted from screens placed in the abandoned holes from the excava-

tions. A total of app. 6,000 litres of oil-contaminated groundwater and app. 1,000 tons of oil-

contaminated soil have been removed.

Step 3 will be to restore the holes and continue the groundwater extraction from screens

placed in the holes.

11.3 Conclusion and future activities

Heavily contaminated soil was excavated. Locally there is still residual contamination in the

soil. Screens for remedial pumping have been installed in the holes from the excavation. The

extracted water was led through an oil/water separator. Subsequently the groundwater was

analysed, and the cleaned water was recirculated. Methods for mobilization of the residual con-

tamination and shorten the treatment duration is under consideration.




12. Closing of coal mine

Project Management of the Closure of Coal Mining in Svalbard.

By Frank Holmgaard, Rambøll Norway


At Spitsbergen, Svalbard the Norwegian state has run two coal mines since 1934 via the com-

pany Great Norwegian Spitsbergen Coal Company (SNSK). The largest coal extraction took

place in the period 2001-2016 from the two mine fields. In 2017 it was politically decided to

close down the coal mines.

It is estimated that a total remediation of the sites will cost app. 150 million € and last 4 years.

The annual cost to keep the installations and plants open is app. 20 million €.

Conditions for closing of the mines and remediation have been stipulated in the operation per-

mit.

12.2 Method

A feasibility study was made including the history of the activities during the operating period

1934-2016 and a few previously performed investigations to assess the costs of remedial ac-

tions in connection with closing down the mines. Physical environmental investigations were

not made in connection with the feasibility study.

12.3 Results

Contamination with fuel, oil, PAH, PCB, PFOS/PFOA, asbestos and metals from coal and mine-

tailings is expected to be found. The total amount of contaminated soil is assessed to exceed

150,000 tons.

The plan is to restore the original landscape. Part of the restoration is to restore 1.5 tons of

soil and materials used for infrastructure etc. to the original extraction sites. This work is esti-

mated to last more than 50,000 man-hours, more probably 70-80,000 man-hours.

12.4 Conclusion and reflexions for future process

The conditions for remediation and restoration is vaguely defined: “…. By full or partly decom-

missioning of the company the SNSK must do everything possible to prevent danger of con-

taminations and provide for the operation site to be restored to an environmentally satisfactory

state….” Hence, measurable demands have not been defined.

The uncertainties of the remediation demands increase the costs of the remediation and resto-

ration. The demands must be negotiated between the Norwegian state as the owner and the

Norwegian state as the environmental authority. The Norwegian environmental standards only

count as guidelines at Svalbard.

Next step is to perform physical investigations of the extent of the contamination and subse-

quently prioritize the action.


Another challenge is that the background values for the area are unknown, e.g. background

values for arsenic might be higher in this area than elsewhere due to the coal occurrence at

Svalbard.

When assessing the potential remedial actions the following will be taken into account: techni-

cal methods, cost efficiency, risk-based approach to studies and remediation, accept criteria

for action, and sustainability.

They suggest also to use a risk-based approach to investigations and remediation in

Greenland.


Q: Could you use the mine as depot for contaminated soil ~ a monitored waste dump?

A: That could be a possibility – it depends on water level conditions in the mine and the con-

taminants occurring at the site.

Q: There must be a very high content of coal dust in the soil at the mines – it is a good sor-

bent for PCB and oil compounds. Landfarming will probably not work, if the contamination is

not accessible, because it is too solidly sorbed to the soil. Maybe the contamination is not even

a problem – if it is firmly sorbed to the soil, it will not be flushed out to the water environ-

ment?

A: In Norway the “polluter pays”-principle applies, so the pollution cannot be abandoned.

Comment: They need to define accept criteria, including how much contamination is accept-

able to leave behind after a remediation.

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