Former Korsør Fire Academy

The site is an active fire academy heavily contaminated with PFAS due to former use of aqueous film forming foam that contained significant amounts of PFAS. These contaminants have been nicknamed “forever chemicals” due to their persistent properties, which poses a challenge to the common remediation practices. Based on the need for adaption and development of new technologies for investigation and remediation of PFAS-contaminated sites, a partnership was established in 2022 to facilitate this by offering access to the first national PFAS-test center. The partnership consists of Slagelse Municipality (site owner and local environmental authority), RESC Rednings- og SikkerhedsCenter (the onsite active fire academy) and Region Zealand (regional environmental authority).

The partnership wishes for this test center that it will become a point of gathering for knowledge on PFAS contamination by contributing to the development of viable solutions for investigation and remediation of PFAS contaminated sites nationally and internationally. Onsite meeting facilities support this.

Regional geology and geomorphology
The Korsør area is dominated by glacial deposits, primarily clay/sandy tills and meltwater-sand/clay from the last Ice age. Post glacial deposits such as peat, freshwater sand and clay are deposited in low areas, and marine sandy and clayey sediments appear close to the sea.

The glacier advance, forming the majority of the landscape around Korsør, is related to the so-called Great Belt Advance, which transgressed the area approximately 17-18.000 BP. During the retreat of the Great Belt glacier, a number of minor re-advances formed the characteristic lobate marginal moraines that are scattered from Langeland and northwards to the Island of Samsø:

The general geomorphology of the area is dominated by a mixture of ice-marginal landforms, such as marginal moraines, overprinted by a so-called dead-ice relief with numerous classical ice-lake hills and kettle holes:

The Ice-lake hills were formed in ice-lakes close to the margin of a retreating glacier front. The lakes were gradually infilled with meltwater-deposits and when the surrounding ice melted, the lake sediments formed characteristic hills. During periods with strong melting or rain events meltwater is flushing sand/silt/clay into the lakes. Mudflows are also creeping into the lakes depositing flow-tills on the meltwater sand/silt/clay. During the deposition the surrounding ice is still active and push and deform the sediments, thus resulting in very complex geological conditions.

Korsør Fire Academy is situated on such an ice lake hill with a top level of approximately +20m DVR90 next to a local marine inlet “Korsør Nor”:

The hill is one of several characteristic hills in the area, and it is primarily consisting of clay till overlain by meltwater sand/clay/sandy flow-till in the upper 10-15 m. To the west marine deposits, dominate the raised marine foreland towards the sea. Below cross-section is illustrating the distribution of sediments under the Korsør Fire Academy. It appears at least three to four different levels of groundwater is present. One is approximately +10,6 m DVR 90, another groundwater table, is situated at +8,2 m DVR 90, a third one is situated +5,6 m DVR 90 and finally the groundwater table on the lower area is situated about + 1,7 m DVR 90 falling towards the sea to the northwest. Apparently, the groundwater is seeping towards NW and the sea. The different groundwater levels implies that the geology is complex and that the sediments are deformed.

The site has hosed a fire academy since 1969 and to the present day. Until 2001, the fire academy used fire-fighting foam containing PFOS. It is the fire academy activities, which have caused extensive PFAS contamination. Overview of the site and its surroundings:

In soil, PFOS and PFHxS are the most dominant components (see figure below). The highest concentrations of PFAS Σ4 (PFOA, PFOS, PFNA, PFHxS) are found in the top soil (0.2 m bgs) and as high as 1,447 µg/kg dry matter. In addition, sediment samples from a ditch connecting the site to Korsør Cove revealed concentrations up to 3,177 µg/kg dry matter. Near certain fire training facilities, significant content of hydrocarbons in soil is also reported.

In the secondary groundwater located at 1-6.5 m bgs, PFAS Σ4 is detected in every water sample extracted and in concentrations ranging from 90-123,000 ng/l. The composition of PFAS components in groundwater is dominated by long-chained PFAS in the source area, whereas the shorter-chained PFAS components are more prevalent downstream of the site (see figure below). Only one water sample, which was extracted next to a leaking well, contained hydrocarbons (B4).
The general groundwater flow pattern is towards north-north east in the direction of Korsør Cove. However, the geology in the area is highly complex (see Geology), wherefore the groundwater in which the wells are screened may not be a continuous aquifer.

In the surface water of Korsør Cove, concentrations of the specific component PFOS of up to 77 ng/l is detected near the coastal line facing the site. Surface water collected within the ditch connecting the site to Korsør Cove contains significantly elevated concentrations of up to 34,000 ng/l. Since PFAS compounds preferentially accumulate in the air-water interface, a foam sample from the Cove has been collected at the easternmost point of the Cove. The foam contained 16.000 ng/l of PFOS.

The site investigation also included assessment of biota living in the Cove and grass growing on the meadow downstream of the site. Both demonstrating accumulation of PFOS.

Since 2021, all drain water from the site has been collected and treated in an on-site P&T plant (illustration below). In addition, since 2023, on-site infiltrating water collected immediately downstream of the site is also treated in the P&T plant. This to limit further leaching of contamination from the site to the surroundings. The treated water is discharged to a nearby WWTP.

More details on the site can be found in the collection of Technical documents (in Danish). 

By car

Access conditions for heavy vehicles are good.

By public transportation
The nearest bus stops (line 901) are located within a 300 m walk from the PFAS-test center and operates at half hourly services to and from Slagelse Train Station and Korsør Train Station. These train stations are connected to the main public infrastructure. Please consult the public transportation guide for details: www.rejseplanen.dk.

Entering the meeting facilities
Upon arrival, consult the reception. Opening hours Mon-Thurs 07:30-15:30, Fri 07:30-12:30.

How to book meeting facilities
Approach the administration at RESC for bookings on T: +45 58 57 97 00 or E: resc@slagelse.dk. The booking is confirmed once the administrator has accepted the request.

Access to the on-site staff canteen
Approach the administration at RESC for ordering of lunch on T: +45 58 57 97 00 or E: resc@slagelse.dk. The booking is confirmed once the administrator has accepted the request. Be aware that payment is via invoice only.

Please note, that the order must be placed 8 days prior to the visit to accommodate planning.

Meeting facilities
4 meeting rooms, which fit approximately 10-50 participants. Each meeting room is equipped with a screen or projector. There is access to a coffee machine. See Access to the site for info on how to book the meeting facilities.

Canteen
The on-site staff canteen is available to users of the test center. Please note, that an order must be placed prior to the visit. See Access to the site for more details.

Toilets
Several toilets are accessible on-site within opening hours: Mon-Thurs 07:30-15:30, Fri 07:30-12:30.

Some are located next to the meeting facilities, others near the canteen. If in doubt, please approach the reception.

Wireless internet access
The on-site active fire academy, RESC, is kindly offering access to their WIFI in the buildings. Instructions on login is provided on-site.

Soil
Possibility of sampling of soil from the site and manual sampling of sediment from the meadow. The latter is §3 protected after The Protection of Nature Act, wherefore restrictions apply. A permission is required for some activities. If in doubt, address Slagelse Municipality (teknik@slagelse.dk), which is also the authority that processes applications and issues permits.

Groundwater, surface water and drain water
A number of monitoring wells have been installed at the site and the surroundings. This facilitate easy access to sampling of groundwater. See the collection of Technical documents for details on location, depth etc.

Sampling of surface water and e.g. ocean foam is possible.

Drain water from the site is collected in buffer tanks and may be used for e.g. testing of P&T technologies.

Air
Contamination of soil vapor and indoor air is to date not investigated at the site. Soil vapor extraction and passive sampling of indoor air is however an opportunity.

Other
As part of the preliminary site investigation, accumulation of PFAS was observed in fish and grass sampled in Korsør Cove and the meadow, respectively. Sampling may be repeated. Be aware, that fishing in Korsør Cove requires a common Danish Fishing License, which can be purchased at https://fisketegn.dk/.

The site pavement and surfaces of e.g. drains is covered in PFAS. Testing of methods for cleaning of such is possible.

Testing facilities
The site is equipped with water taps as well as grounded 220V, 16A and 400V, 16A electrical outlets. A water and power meter is installed at these outlets nearby the permanent P&T plant. Project owners are expected to cover expenses related to significant water and power consumption.

A pump fitted with an outlet for access to collected drain water and tubing for easy discharge of process water is installed nearby the permanent P&T plant. Process water is returned to the buffer tanks to ensure sufficient treatment via the permanent P&T plant. Thus, this specific location is suitable for testing of P&T technologies. Suggested areas for various testing purposes are marked on below map:

If requested, we may install an on-site test container.

Project owners
In order to ensure, among other things, optimal conditions for each individual project, Region Zealand must approve all projects on behalf of the partnership that runs the PFAS-test center. Please submit a project application with, in all confidentiality, full transparency in relation to technical and chemical details. Template is available here: dansk, English.

The project owner holds the sole responsibility of obtaining necessary permission(s) of the local municipality. Documentation must be shared with Region Zealand.

Before access to the site, we also ask you to sign an agreement, which commits the project owner to take responsibility for any damages under Danish law and for not increasing the cost of future efforts to remediate the contaminated site.

All visitors
Be aware that the site is an active fire academy; hence show consideration for the daily operation. Also, please treat the facilities with respect and tidy up after yourselves.