THE DANISH SOLUTION: A BLUEPRINT FOR CLEAN SOIL - An introduction to the Danish soil remediation solution
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FORORD 1
THE DANISH
SOLUTION:
A BLUEPRINT
FOR CLEAN SOIL
An introduction to the Danish soil
remediation solution
CMYK
Logo / State of Green
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2 FOREWORD
CLEAN SOIL – A FRAMEWORK
FOR TACKLING SOIL
CONTAMINATION
In Denmark, we have developed Action based on four priorities Who foots the bill?
solutions to soil contamination issues Subsequently we have developed methods To ensure continued clean-up of contam-
for more than three decades; and the to assess, which sites need urgent atten- inated soil, we have had to address the
results show that the solutions work. tion, and which can wait. issue of responsibility and financing. With
Denmark is better equipped than ever potentially thousands of contaminated sites
to manage soil contamination towards across Denmark, the public coffers would
a sustainable future. This publication The regional authorities prioritize their quickly run dry if the authorities alone
will give you the key to our approach. remediation efforts towards: were to finance remediation efforts on all
property.
The early 1970’s were central to how we • Contaminated sites threatening our
manage environmental challenges in groundwater resource. Therefore, the company or contractor re-
Denmark, as visible signs of the effects of sponsible for damage to the environment is
industrialization became a wake-up call for • Contamination where evaporation from also responsible for remediating it. However,
the entire country. Denmark faced serious the soil is causing a health risk. in cases where it is not possible to impose
environmental problems. Fish lay dead in an environmental responsibility, the public
inland seas and rivers, and the ground- • Sites where there is a risk of human authorities finance the remediation project.
water was seriously polluted. The latter is contact with the contaminated soil.
particularly problematic, in a country, where The Danish recipe for soil remediation
drinking water is supplied almost entirely • Contaminated sites posing a risk to We still have contaminated sites in Denmark,
from our groundwater resources. nature protection areas and our lakes, and we will for many years to come, but we
fjords, streams and rivers. are well underway in dealing with the task.
For soil contamination, we needed to We have found a framework for identifying
provide a framework for identifying and and prioritizing soil-contamination sites, and
prioritizing soil-contamination sites, while at Developing innovative solutions we are continuously developing green tech-
the same time developing green technologi- In the Danish approach, it has been impor- nological solutions to remedy the sites.
cal solutions to remedy them. tant to ensure that public and private actors
have the best possible conditions to adopt The goal is a sustainable future without soil
Mapping as a first step to clean soil new green technologies and find new solu- contamination - this publication contains our
But where to begin? In the early 1980s, we tions to soil contamination challenges. recipe to reach it.
had no overall experience with soil remedi-
ation. We were literally entering uncharted With the tasks and priorities identified, the I trust you will find plenty of inspiration.
territory and as a consequence, we initially public authorities in Denmark have been
began by mapping contaminated sites. able to support and fund new innovative
projects in collaboration with the private
Today, we have identified more than 35.000 sector and universities. This has enabled us
Danish properties and sites that have been to develop unique solutions to different soil
classified as either contaminated or poten- contamination challenges.
tially contaminated.
The public involvement has also ensured a
high level of data transparency, as all innova-
tions have been made publicly available,
along with the data from the site mapping
and investigation processes.
Photo by Claus Bjørn Larsen
Kirsten Brosbøll
Minister for the Environment
December 2014
CONTENT 3
CONTENTS
Foreword by the Minister 2
Introduction 4-5
Knowledge and research 6-7
Regulation 8-9
Technology 10
Cases 12-13
Challenges 14-15
Contributors
Danish Environmental Protection Agency
The Information Centre on Contaminated Sites
Krüger A/S
RGS90 A/S
COWI A/S
NIRAS A/S
Editors
Operate A/S: Esben Würtz Sørensen
Grontmij A/S: Lene Mundus
4 INTRODUCTION – THE DANISH SOLUTION
GETTING SMART
ABOUT CLEANING
OUR SOIL
Denmark is a small country in which producers and users, or dry cleaners. Sites If remediation is deemed necessary, the
groundwater is the primary source of can also be included in the mapping effort work will then commence.
drinking water. With contaminated due to reports from companies or property
sites in their thousands, it has been owners who detect contamination on their Depending on the type and extent of
paramount to develop smart ways to property. This mapping effort has been contamination, the remediation can take
identify and prioritize which sites to re- ongoing since the early 1980s and has so far place at the contaminated site (in-situ) or
mediate. Here are the key components resulted in more than 35,000 sites cate- by transporting the contaminated soil to a
of Denmark’s unique soil remediation gorized as “contaminated” or “potentially facility for treatment (ex-situ).
system. contaminated”.
The remediation can be financed by the pub-
In the autumn of 2014, the second phase of From suspicion to certainty lic authorities or as a voluntary remediation
one of Denmark’s biggest soil remediation At stage one, the initial mapping is of course by private building developers. In the latter
projects began in the wind-swept dunes on based on a suspicion of possible soil con- case, the preferred measure will often be to
the country’s North Sea coast. The soil con- tamination. Therefore, each site mapped at transport the soil for ex-situ treatment.
tamination in the Kærgård Plantation took stage one is subsequently subject to a pre- The public authorities traditionally sets
place between 1956 and 1973, when the liminary investigation. The public authorities high standards for remediation measures,
Grindstedværket chemical plant released finance these preliminary investigations, in order to stimulate eco-innovation that
up to 340 tonnes of chlorinated solvents and the investigations themselves are often benefits the public health as well as the
into Grindsted stream and the neighbouring carried out by private consultancies. environment.
plantation.
All data gathered from the investigations are New uses for purified soil
Now, 40 years later, the regional authorities collected in a national database, and the site Once the remediation measures have been
of Southern Denmark are in charge of the is classified as a “stage two knowledge site”. completed, the purified soil will be put to
massive operation, where so far two pits good use. For example as coastal protection,
of contaminated soil have been excavated The preliminary investigation is designed landscape modelling or as noise barriers
and a further two will be remediated during to determine whether the site may pose a along roads with heavy traffic.
phase two. When phase two is completed, risk to human health, water bodies, natural
the final two pits will remain for remedia- habitats or the groundwater. If this appears Danish legislation also has a provision that
tion. to be the case, an in-depth investigation is requires building developers to report
launched. movements of soil from classified areas in a
Although on a large scale, this is a good national register.
example of how all Danish soil remediation Testing soil thoroughly
works. before remediation Soil quality criteria guide efforts
If the suspicions are not allayed by the When is society satisfied with a remediation
A five-step approach to clean soil preliminary investigation, and the pollution effort of a contaminated site? Denmark
The first thing to notice is that the regional might pose a threat to the environment or has guideline criteria for soil, groundwater,
authorities are in charge of soil remediation. human health, a more thorough, indepth water bodies and evaporation to help guide
In serious contamination cases, like the one investigation of the soil is carried out. soil remediation efforts. These four forms of
in Kærgård Plantation, the national author- criteria are used to help evaluate the severi-
ities have sometimes stepped in to assist These investigations are carried out by ty and extent of a site contamination.
the remediation efforts, but the rule is that qualified professionals, who follow guide- The soil quality criteria set limits for a num-
the regional authorities are free to prioritize lines from the Danish Environmental Protec- ber of substances to ensure that the soil can
remediation efforts. tion Agency to prevent inadequate sampling be used freely and without fear of exposure,
and minimize the risk of deliberate cheating. for example on farmland, in private gardens,
The first step towards remediation of at daycare centres and on playgrounds.
contaminated soil is to map potentially con- The investigation aims to map the extent of
taminated sites. Authorities investigate this the contamination, quantify the risk to hu-
by studying data on the historical use of spe- man health and the environment as well as
cific sites. This means surveying for specific suggest a remediation measure. When the
company types like gas stations, gasworks, investigators are done with this investiga-
chemical companies, metal goods producers, tion, the regional authority decides whether
wood preservation manufacturers, pesticide remediation is necessary or not.
INTRODUCTION – THE DANISH SOLUTION 5
Year Content
1971 The Ministry of the Environment is established
1974 The Danish Environmental Act enters into force
1984 The Act on Chemical Waste Deposits
The groundwater quality criteria are applied
for contaminations that pose a risk to the
groundwater resource. Because of a relative 1992 The Oil Sector’s Environmental Pool is established
shortage of surface water, Denmark has
always relied heavily on groundwater for its
1996 Public programme for development of clean-up and
water supply. Groundwater is less exposed
remediation technologies relating to soil contamination
to pollution than surface water, the water
is of higher quality, and it requires less
treatment.
1998 Guidance document on how to remediate
contaminated sites
€ 75 million: 2000 Danish Act on Contaminated Soils
money spent on soil and
groundwater remediation in
Denmark in 2012. 2007 Amendment to the Act on Contaminated Soil
exempting soil within city limits from the mapping
requirement
The groundwater quality criteria apply to
groundwater resources that are being used
2014 Amendment to Danish Act on Contaminated Soil to
as drinking water. The criteria fundamen- include waterbodies at risk from leaking
tally aim to ensure that the groundwater contaminated sites
is drinkable with little or no treatment. For
some substances, these criteria are even
lower for groundwater than for drinking
water, in order to account for the additional
contribution of substances from the water
pipes delivering the water to the consumer.
Money spent on soil and groundwater remediation in Denmark in 2012
Finally, the limits on evaporation aim to se-
cure that the site can be safely used for even
%
. € 50
the most sensitive use (daycare centres,
7 mio
5 4%
kindergartens and playgrounds). ns io. €
e gio s 4m
R tie . € 8%
The three components in the pali 9 mio
ci at
e 4%
o. €
Danish solution St mi
ni
5
€ 7%
Mu
e
The Danish approach to soil remediation nc mio.
%
owes its success to three key components: 8 . 27
e
ef
ca
ce
hD
knowledge, regulation and technology. €
n
ura
nis
m io.
s
The da
l + in
Each has been crucial in pushing forward
d 13-27
innovation and remediation efforts towards
oo
a future with clean soil.
P
spen
nt al
e
We will elaborate on these three compo-
e
m
t
iva
n
nents in the following sections.
Es
o
r
r
lp tim
vi
na ated
n
additio ’E
The n ies
Oil Compa
Source: Depotrådet 2012
6 KNOWLEDGE AND RESEARCH
Water sample. Protection of the groundwater resource is crucial in Denmark, as
the country relies on it for drinking water.
Photo by The Information Centre on Contaminated Sites
KNOWLEDGE AND RESEARCH 7
THE FOUNDATION
FOR TACKLING SOIL
CONTAMINATION
Research into the effects of soil tion, data about groundwater, geological soil This ensures that companies are always
contamination, and new methods to composition, and historical land use is also well-informed about the newest technolo-
remedy these effects, have been pivo- collected and used by the public authorities gies and developments within the field.
tal in the Danish solution. Knowledge as well as the private sector. This helps the
institutions routinely contribute to authorities to make the optimal decisions It has also ensured a vibrant Danish private
remediation projects, and data about regarding new remediation projects. sector within soil contamination and it is es-
contaminated sites is collected and timated that private companies in the sector
made available to professionals and Moreover, the regional authorities have employ around 1,000 people.
the public in a national database. developed a number of IT tools and assess-
ment tools which help them prioritize their Ongoing research at national level
When prospective buyers of a house in efforts. How do you detect gas from contaminated
Denmark want to know whether their new soil intruding into the indoor air? Environ-
home sits on contaminated soil, they can The Regional Information mental Project number 1590 examines the
access the ”Area Information” database on Center on Contaminated Sites possible methods to do just this.
the Environmental Portal. They can then Along with the database, authorities and
download a soil contamination certificate on soil professionals have a powerful tool in the The Danish Environmental Protection Agen-
the property free of charge. Regional Information Center on Contaminat- cy regularly funds such research projects
ed Sites (RICCS). The Center is run by the five within the field of soil contamination. A
The Danish Environmental Portal is an online Danish regional authorities and it collects, condition for this funding is often that the
database, created by a partnership consist- analyses and disseminates knowledge on results of the projects are made available to
ing of the Danish municipalities, the five soil and groundwater contamination. the public.
regional authorities and the Ministry of the
Environment. It aims to aid the authorities in The Center is a platform on which regional The projects provide valuable new informa-
performing their regulatory functions. authorities develop and exchange knowl- tion that supplements the knowledge and
edge on best administrative practices and research conducted by Danish knowledge
The service for private citizens is just one new technology. institutions. Regional development benefits
visible example of how the data gathered on as well.
soil contamination is benefitting continued The Center also conducts a number of devel-
efforts for cleaner soil. opment projects and the results are made Universities are crucial
public as reports or tools for soil contamina- Soil contamination, investigations and reme-
The data in the database has been collected tion professionals. diation measures often demand technology
over decades and it is a powerful tool for pub- that has not yet been developed. Therefore,
lic authorities and soil professionals alike. The Center also has an educational respon- Danish knowledge institutions play a key role
sibility in that it holds specialized courses for in developing and testing new technology.
12: regional soil professionals. It also monitors
the number of new research all sources of literature on soil contamina- Integrating the Danish universities and
papers on soil and groundwa- tion in Danish, and these are added to a knowledge institutions into the soil contam-
ter contamination published database (called LIX). ination value chain ensures the highest level
by the Danish Environmental of professional expertise.
Finally the Center issues a magazine four
Protection Agency in 2014.
times a year, solely dedicated to new know-
ledge on soil contamination.
DKJORD – the database on
Denmark’s soil No commercial interests
The regional authorities collect huge help knowledge sharing
amounts of data. Data from the ongoing Because the regional and national authori-
mapping of contaminated and potentially ties have no commercial interest in the
contaminated sites in Denmark as well as knowledge obtained from the large number
the many site investigations, test and pilot of projects they are responsible for, they
projects, and actual remediation projects. function as a knowledge provider for private
companies.
This data is uploaded and stored in a central,
database called ‘DKJord’ (‘DK Soil’). In addi-
8 REGULATION
THE RIGHT FRAMEWORK
FOR TACKLING SOIL
CONTAMINATION
The Danish Act on Contaminated Soil The process is as follows:
from 2000 is one of the most compre- • Mapping: based on data on historical Cleaning up gasoline retail sites
hensive pieces of legislation on soil use of the site (stage-one knowledge One such voluntary and very success-
remediation in the world. It is the result level). ful arrangement was agreed with the
of years of development for the right • Preliminary investigation Danish oil industry in 1992.
legal framework on soil contamination. (stage-two knowledge level): investi-
gation to identify underground storage Nine oil companies operating
Before 1974, and the entry into force of tanks etc. from historical archives. Soil petrol stations in Denmark jointly
the Danish Environmental Protection Act, it and groundwater samples are taken to estab-lished a fund by charging DKK
was not unusual for companies to dispose decide whether or not the site is polluted. 0.01 for each litre of petrol sold to
of waste chemicals by dumping barrels • Further investigations to find the consumers.
into landfills. Little was known about the extent of the pollution and perform a risk
associated long-term health and environ- assessment. This fund was subsequently used
mental risks, but the Act on Chemical Waste • Suggestions for possible remediation to finance remediation of about
Deposits in 1984 changed that. The Act also measures if the pollution poses a risk. 9,800 sites previously used for petrol
heralded a massive three-decade effort to • Remediation. stations.
remediate soil contaminations. • Operation and control
(if it is a longterm remediation scheme). The massive task was completed in
The Act on Chemical Waste Deposits was 2011, when the last contaminated
the first legislative Bill to be passed which The polluter pays principle soil excavation was completed.
solely addressed soil contamination. The Act For many of the contaminated sites, the
charged the regional authorities in collab- question of liability has proved more than The arrangement was approved in
oration with the municipalities to mapping difficult. Contamination often occurred 1994 by the Danish competition
the existing chemical waste deposits and years or even decades ago, meaning the authorities as well as the EU.
landfills, and the results showed a total of perpetrating companies could be bankrupt
500 contaminated sites. or closed. Even if the companies are still op-
erating, it is often difficult to establish clear On the other hand, the health risks asso-
It was estimated that remediation efforts liability for the contamination. ciated with this kind of contamination are
would take 10 years, with a price tag of EUR negligible compared to other risk factors.
50 million. Therefore, it has been paramount to es- However, until 2007 this soil technically had
tablish a clear “polluter pays principle”. The to undergo the same scrutiny as the more
Introducing the five-step Danish Act on Contaminated Soil from 2000 classically contaminated sites.
principle for remediation did just that.
By 1993, the national mapping effort of To better focus soil remediation efforts on
contaminated sites showed that the total The Act is the most comprehensive piece of the truly pressing sites, in 2007 the Danish
number of contaminated sites might actually legislation on soil contamination to date and authorities introduced an amendment to
be as high as 10,000, and the estimated it sets out clear criteria for who has to pay the Act on Contaminated Soil, exempting
costs of remediating the contaminations had for remediation efforts. lightly contaminated soil from diffuse
sky-rocketed to EUR 3 billion. sources within city limits from the mapping
For soil contamination committed in the requirement. At the entry into force of the
One very pressing issue was to develop tools past, the public authorities step in when legislation, it was estimated that at least
to process these sites in a uniform manner remediation is not covered by insurance or it 90,000 sites could be exempted from the
so that efforts could be focussed where they has been impossible to reach a settlement mapping requirement. The Danish author-
were most needed. Therefore, in 1998 the on voluntary remediation. ities followed this move with an extensive
Danish Environmental Protection Agency information effort aimed at citizens and mu-
published a guidance document on how to For any new soil contamination, the polluter nicipalities. The aim was to provide advice on
remediate contaminated sites. The guidance pays for investigation and remediation. how to minimize risks from lightly polluted
document introduced the five-step approach sites – e.g. washing hands, using clean soil
to tackling soil contamination. Soil classification for cultivation and cleaning vegetables.
In urban areas, the soil will often contain
traces of diffuse contamination from indus-
trial emissions or traffic.
For example lead, cadmium or PAHs.REGULATION 9
Monitoring the movement
of contaminated soil
Though the mapping requirements have
been relaxed for certain types of soil, it is
still vital to have up-to-date data on the
whereabouts of contaminated soil.
Therefore, the legislation on soil move-
ment introduced an obligation to notify the
municipal authorities when soil from urban
areas (area classification sites) is moved –
for example by contractors. This obligation
to report movement of soil already applies
to mapped sites and soil from road areas, as
this soil has often turned out to be contam-
inated.
Screening for threats to recipients
While soil remediation initially focused on
protecting human health and groundwater,
in recent years Denmark has also made
moves to strengthen the protection of water
bodies (coasts, streams, rivers, fjords and
lakes).
90,000:
The number of sites in
urban areas exempt from the
mapping requirement.
Currently, the regional authorities are
working to screen contaminated sites that
may pose a risk to nearby water bodies. This
means investigating whether contamination
from, for example, metalproducts facto-
ries, dry cleaners or old landfills can pollute
streams, rivers, lakes or fjords.
The authorities first establish the concen-
tration level of the contamination in ques-
tion. Afterwards, the distance to nearby
bodies of water is established. Thirdly, the
screening calculates the dilution of the con-
tamination once it enters the body of water.
Lastly, the screening calculates the overall
risk of the particular contamination for the
body of water.
The screening is expected to be
completed by 2019. Soil sampling. Photo by NIRAS A/S10 TECHNOLOGY
DEVELOPING THE
TOOLS FOR
THE JOB
New problems call for new solutions. The benefits of the “Triple Helix” Examples of current development
Denmark has developed a frame- Crucial in the development of new technol- projects include:
work in which public demand for soil ogies has been the interplay between public • Jet injection into glacial clay till deposits
remediation technologies drives authorities, the private sector and knowl- • Isotope fractionation
innovation. The resulting technologies edge institutions (Triple Helix). • Phytoremediation of heavy metals using
have been made publicly available to tropical ferns
further stimulate innovation and to When public authorities are charged with • Electrokinetic remediation of heavy-met-
keep costs low. remediation of a contaminated site, the als-contaminated soils
contractor is often required to develop or • Horizontal directional drilling
How do you remove chlorinated solvents use high-tech insitu solutions. Furthermore, • New methods for indoor climate reme-
from contaminated clayey soil? This prob- private remediation companies are encour- diation
lem has caused headaches for soil remedi- aged to form partnerships with research
ation experts as remediation technologies institutions. In 2012, the regional authorities invested
that can remove solvents in sand and gravel a total of EUR 2.2 million on development
often fail at sites with clayey soil types. National testing sites projects, and a total of sixty development
for technologies projects had been set up , many of which
However, the company NIRAS A/S, in To create optimal conditions for innovation were being run through public-private
collaboration with the specialist American of solutions, the regional authorities have partnerships.
company Geosyntec Consultants and the jointly decided to form a common national
Capital Region of Denmark, have developed network of test sites. The Danish Environmental Protection Agen-
a solution: removing chlorinated solvents cy also administers a pool for development
by electrokinesis. The Danish regions obviously have a natural of technology within the field of soil and
interest in developing new and cost-effec- groundwater contamination. The pool has
The award-winning technology is a good tive methods to tackle the future remedia- been established to fund projects for EUR
example of the Danish approach to devel- tion processes. Moreover, they are obligated 0.8 million in 2015.
oping soil remediation technologies. to support business development in their
60:
catchment area.
Innovation with public backing
the number of development
Authorities in Denmark realised early on The network consists of a number of projects running in 2012 as
that the private sector needed a public different test sites in terms of geology, a result of the regional
driver to stimulate innovation of soil reme- groundwater, and contamination. The sites authorities’ commitment
diation technologies. are open to small-scale as well as large-scale to developing new soil
testing of a wide variety of different types of
remediation technology.
Therefore, the government set up a public remediation processes and technologies.
programme in 1996 to develop clean-up
and remediation technologies relating to Millions of EUR to develop
soil contamination. new technologies
At the same time, the regional authorities
Since the programme started, about 292 are co-funding a wide range of test and
projects have been initiated, of which 120 demonstration activities which involve
have related to testing various remediation stakeholders from the knowledge sector as
technologies. well as private companies and international
stakeholders from all parts of the world.
The remaining 172 projects deal with
developing innovative investigation and re-
mediation methods and enhancing general
knowledge about soil contamination.
In 2002 the technologies developed under
the programme were evaluated and the re-
sults showed that the programme is making
a considerable contribution to the develop-
ment of technology in the area.TECHNOLOGY 11 Soil sampling. Photo by NIRAS A/S
12 CASES
CHLORINATED SOLVENTS:
THE SKULDELEV SITE
A major contamination with chlorinat- More than 1,000 litres of undiluted con- Results: restoring the city pond
ed solvents located beneath a city pond tamination with chlorinated solvents was The last part of the remediation effort
forced the regional authorities to get pumped away from beneath the pond. consisted of sealing leaks in the sewer to
creative. minimize the risk of evaporation from the
Subsequently the soil was cleaned using contaminated soil.
For ten years between 1958 and 1968 a heat treatment, removing half a tonne of
metal manufacturer in the city of Skulde- chlorinated solvents. After the remediation, the pond will be
lev used chlorinated solvents to degrease restored but the effort will continue in other
metal. The wastewater was legally directed Here too the company Niras tested a new affected parts of Skuldelev.
into the sewer. remediation technology using electrokinesis
to clean the soil. This technology has since
Forty years later, authorities began inves- gone on to win awards.
tigating the site and uncovered a major
contamination with chlorinated solvents Furthermore, the regional authorities used
beneath the city pond. a technology where unique iron compounds
were added to the contaminated soil to
The main risk was from evaporation from the break down the contaminant compounds.
contaminated site, which posed a health risk The method involves adding a special kind of
to nearby residences. Furthermore, the au- clay (bentonite) and iron particles.
thorities wanted to stop the contamination
from polluting the groundwater resource. Finally, the regional authorities took meas- 1,000 litres
ures to secure several of the adjoining hous- The amount of undiluted
Solution: electrokinesis and iron es from vapours from the contamination. contamination pumped
The remediation effort began in 2008, and The solution consists of constructing new from beneath the pond in
the regional authorities have employed a flooring that allows for ventilation beneath
Skuldelev
number of measures. the houses.
Soil remediation at the Skuldelev site. Photo by NIRAS A/SCASES 13
GASWORKS:
THE ØSTRE GASVÆRK SITE
Previously a major gasworks in Den- Therefore, the authorities established a
mark’s capital, Copenhagen. Now the biological water treatment plant on the
previously heavily contaminated site gasworks site in 2002.
is hosting a cultural center and recrea-
tional area for Copenhageners. The facility uses new method to purify
contaminated groundwater by adding pure
For nearly a century the gasworks, Øs- oxygen before leading the water through a
tre Gasværk (Eastern Gasworks) was in sand filter.
operation in Copenhagen. Built in 1878, the
gasworks was expanded several times with Results: Restorating the city pond
new gas containers until it was decommis- And the methods has proved very efficient in
sioned in 1969. removing tar compounds, like BTEX, naptha-
lenes, PHAs, phenols. The purification pro-
By the end of the 1980s the authorities cess gets rid of between 95 and 99 percent
decided that the site needed remediation, of these compounds at an estimated price of
but investigations revealed such heavy con- EUR 1-2.5 per cubic meter of contaminated
tamination, that it was decided to seal the water.
site and capture evaporating gasses.
The technology is less efficient in removing
Solution: ammonium compounds and cyanide from
95-99 percent
Biological water treatment plant the contaminated water. The plant has man- The amount of tar compounds
Previously purification of contaminated aged to remove between 30 and 65 percent that the biological water treat-
groundwater from gasworks has proved of the cyanide from the groundwater. ment plant at Østre Gasværk
more than difficult. The water typically con- manages to remove from
tains a complex mixture of organic and inor-
contaminated groundwater.
ganic compounds that are hard to extract.
Soil sampling at contaminated site. Photo by Grontmij A/S14 CHALLENGES
PREPARING
FOR EXTREME
WEATHER
Sites that were previously consid- There is currently a big push from both New substances demand attention
ered not to be of any significant risk national and regional authorities to fill this Apart from the challenge of climate change,
to the environment may pose a risk knowledge gap with new research. How- the Danish authorities are currently
in the future due to climate change. ever, in the meantime the authorities are investigating a number of substances that
The Danish authorities are working to forced to navigate on the basis of incom- were previously deemed of little concern in
tackle soil contamination in a future plete knowledge. relation to soil contamination.
with increased precipitation. Moreover,
other challenges need to be addressed Near-coastal sites at risk For instance, hazardous perfluorooctanoic
as well. Current projections suggest that rising sea acids like PFOA and PFOS have been found
levels will result in increased flooding. This to accumulate in the soil in areas used for
Increased rain in the winter and less rain in could result in more leaching from contami- fire drills because the substances are used in
the summer. It may seem like a negligible nated sites near the coast but the evidence fire-fighting foam.
change, but changes in the weather have is unclear as to whether this means an
the potential to alter the risk posed by con- increased risk to human health or the envi- Arsenic also poses challenges. The chemical
taminated sites. ronment. has been used in production of sulphuric
acid and is sometimes also naturally present
For instance, recent research suggests that Rising groundwater levels may also pose a in the soil, and can be released to the
more precipitation in the future will result risk. groundwater resource and, by extension, to
in rising groundwater levels and increase the drinking water. Arsenic is hazardous to
leaching from closed landfills. A 2013 study of contaminated sites in the humans and is difficult to remove from the
city of Horsens (a gasworks site and wood groundwater.
This does not necessarily result in an in- treatment plant) calculated that rising
creased risk to the environment, but further groundwater levels could result in 10 to 20 10 to 20% :
investigation is needed to evaluate this. percent more leaching of contamination into the calculated increase in
the nearby fjord. leaching from a contaminated
Planning under conditions site due to climate change
of uncertainty For this reason, regional authorities are cur-
One very real challenge when addressing rently being urged to include climate change
the impact of climate change on contaminat- in their risk assessments of contaminated
ed sites is the huge uncertainty in projec- sites.
tions. What will the temperature increase
be? How much more rain will fall? And when
and how?
What seems to be certain is an increased
level of precipitation, which means that the
current amounts of evaporation, run-off to
streams and lakes as well seepage to the
groundwater will change.CHALLENGES 15 Oblique gravel sedimentation. Photo by The Information Centre on Contaminated Sites
16 FORORD
DANISH EPA
FOR A DETAILED MAPPING OF THE DANISH SOIL AND
GROUNDWATER REMEDIATION SECTOR AND SPECIFIC
CASE EXAMPLES DOWNLOAD THE WHITE PAPER
“A COMMON GROUND FOR CLEAN SOIL” HERE
Draft publication on soil
STATEOFGREEN.COM/FILES/DOWNLOAD/6002
remediation in Denmark
YOU CAN FIND MORE CASES AND CONNECT WITH
DANISH EXPERTISE AT STATEOFGREEN.COM
ABOUT STATE OF GREEN ABOUT THE ENVIRONMENTAL
State of Green is a public-private partnership founded by the
PROTECTION AGENCY
Danish Government, the Confederation of Danish Industry, the Dan-
The Environmental Protection Agency is part of the Ministry of the
ish Energy Association, the Danish Agriculture & Food Council and
Environment. The Environmental Protection Agency is responsible
the Danish Wind Industry Association.
for legislation and is the authority in charge of major national tasks
as well as particularly complex tasks.
H.R.H. Crown Prince Frederik of Denmark is patron of State of Green.
The Environmental Protection Agency prepares legislation and
CMYK
guidelines and grants authorisations in several areas. Further du-
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As the official green brand for Denmark, State of Green gathers all
ties include the monitoring of chemicals and offshore platforms.
Green
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ment and fosters relations with international stakeholders inter- Dark
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ested in learning from the Danish experience.
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