The Akacievej field site - Revision history

Klmos: /* Geology */

2019-04-24T12:43:11Z

‎Geology

Klmos: /* Site history */ Added 2018 investigations to site history

2019-04-21T11:54:14Z

‎Site history: Added 2018 investigations to site history

Klmos at 20:00, 29 January 2018

2018-01-29T20:00:37Z

Klmos: /* Geology */

2018-01-29T20:00:01Z

‎Geology

Klmos: /* The field site: Akacievej, Hedehusene */

2018-01-29T19:56:24Z

‎The field site: Akacievej, Hedehusene

Klmos: /* The field site: Akacievej, Hedehusene */

2018-01-29T19:55:02Z

‎The field site: Akacievej, Hedehusene

Klmos at 09:47, 15 February 2017

2017-02-15T09:47:10Z

Klmos at 09:43, 15 February 2017

2017-02-15T09:43:39Z

Klmos: /* The field site: Akacievej, Hedehusene */

2017-02-15T09:27:37Z

‎The field site: Akacievej, Hedehusene

Klmos at 09:26, 15 February 2017

2017-02-15T09:26:08Z

@@ Line 36: / Line 36: @@
 === Geology ===
-The geology at the Akacievej site is depicted in Figure 2 and consists of a calcarenithic limestone (København Kalk) on top of a bryozoan limestone (Stevns Klint formation), both with a strongly varying hardness.
+A geological cross section at the Akacievej site is depicted in Figure 2 <ref>Mosthaf et al. (2016). [[:Media:Pumping_and_tracer_test_report.pdf|Pumping and tracer test in a limestone aquifer and modeling interpretation]]. DTU Environment.</ref>.
 Due to glacial activity, the uppermost 1 to 5 meters of the limestone are crushed, below which it is fractured with flint inclusions.
 Most of the crushed limestone is in the carbonated sand limestone, but at some places it also penetrates into the bryozoan limestone.
 Bryozoan limestone often contains bank structures.
-However, the bryozoan limestone at the Akacievej does not show strong bank structures and is rather even, possibly due to long-stretched bank structures.
+However, the bryozoan limestone at the Akacievej does not show strong bank structures and is rather even, possibly because the bank structures there are long-stretched.

@@ Line 31: / Line 31: @@
 From 2014 to 2016, several new boreholes were drilled, and various measurements were taken at the site, including different contaminant sampling techniques, geophysical measurements and hydrogeologic analyses.
 In spring 2016, a long-term pumping test and several tracer tests were conducted at the site to further enhance the understanding of contaminant transport dynamics in fractured limestone.
 [[File:Geology_Akacievej_GEO_extended.png|thumb|500px| Fig.2: Geologic cross section at the Akacievej site.]]

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+|
 * Description of the field site
 |}

@@ Line 37: / Line 37: @@
 Due to glacial activity, the uppermost 1 to 5 meters of the limestone are crushed, below which it is fractured with flint inclusions.
 Most of the crushed limestone is in the carbonated sand limestone, but at some places it also penetrates into the bryozoan limestone.
-The bryozoan limestone at Akacievej does not show strong bank structures and is rather even.
+Bryozoan limestone often contains bank structures.

@@ Line 21: / Line 21: @@
 The goal of the remedial activities was to remove the hotspot and to achieve hydraulic control of the groundwater contamination.
 The following actions were taken:
-* Removal of contaminated soil in the source area 0-6 m bgs. Local excavation down to the limestone surface at about 8 m bgs. (limestone is found below ca. 7.5 m bgs.)
+* Removal of contaminated soil in the source area 0-6 m bgs. Local excavation down to the limestone surface at about 8 m bgs (limestone is found below ca. 7.5 m bgs)
 * Establishment of venting pipes and a drainage pipe
 * Remedial pumping with 2.5 m3/h from the upper 6 meters of the limestone to establish hydraulic control
@@ Line 28: / Line 28: @@
 Despite potentially high flow velocities in the fractured limestone, a contaminant plume with a length of approximately 400 m had developed until 2006.
 It grew only little until 2015, as depicted in Figure 1, which also gives the location of the remediation system and the predominating groundwater flow direction.
-From 2014 to 2016, several new boreholes were drilled, and various measurements were taken at the site, including different contaminant sampling techniques, geophysical measurements and hydrogeologic analyses..
+From 2014 to 2016, several new boreholes were drilled, and various measurements were taken at the site, including different contaminant sampling techniques, geophysical measurements and hydrogeologic analyses.
 In spring 2016, a long-term pumping test and several tracer tests were conducted at the site to further enhance the understanding of contaminant transport dynamics in fractured limestone.

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 This revealed high concentrations of PCE and TCE close to where dry cleaners were operating in the years between 1973 and 1975.
 Most of the contamination is likely to be from the operation of the dry cleaning facility and a release during a fire at the site in 1975.
-An array of boreholes was drilled to localize the source zone and to delineate the contaminated area
+An array of boreholes was drilled to localize the source zone and to delineate the contaminated area.
-The contamination was evaluated to pose a potential risk for the drinking water extraction at the Fløng waterworks, which has its closest extraction well about 600 meters north of the Akacievej site.
+The contamination was suspected to pose a potential risk for the drinking water extraction at the Fløng waterworks, which has its closest extraction well about 600 meters north of the Akacievej site.
 In 2007, the most contaminated soil containing PCE as DNAPL was removed and extensive remedial activities were started.
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 === Geology ===
-The geology at the Akacievej site is depicted in Figure 2 and consists of a carbonated sand limestone (København Kalk) on top of a bryozoan limestone (Stevns Klint formation), both with a strongly varying hardness.
+The geology at the Akacievej site is depicted in Figure 2 and consists of a calcarenithic limestone (København Kalk) on top of a bryozoan limestone (Stevns Klint formation), both with a strongly varying hardness.
-Due to glacial activity, the uppermost 1 to 5 meters of the limestone are crushed.
+Due to glacial activity, the uppermost 1 to 5 meters of the limestone are crushed, below which it is fractured with flint inclusions.
 Most of the crushed limestone is in the carbonated sand limestone, but at some places it also penetrates into the bryozoan limestone.
 The bryozoan limestone at Akacievej does not show strong bank structures and is rather even.
 {{Return}}
 |}
 [[Category:Introduction]]

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 * Activated carbon filtering of the pumped water and infiltration of the purified water through infiltration cassettes with an overflow connected to a deep borehole
-Until 2015, a contaminant plume with a length of approximately 500 m had developed.
+Despite potentially high flow velocities in the fractured limestone, a contaminant plume with a length of approximately 400 m had developed until 2006.
-The plume extent and the location of the remediation system are shown in Figure 1.
+It grew only little until 2015, as depicted in Figure 1, which also gives the location of the remediation system and the predominating groundwater flow direction.
 From 2014 to 2016, various measurements were taken at the site, including different contaminant sampling techniques, slug tests, geophysical measurements, analyses of borehole cores.
 In spring 2016, a long-term pumping test and several tracer tests were conducted at the site to further enhance the understanding of contaminant transport dynamics in fractured limestone.

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+|
 == The field site: Akacievej, Hedehusene ==
-[[File:PlumeExtent2006-2015.png|thumb|500px| Extent of contaminant plume in 2006 and 2015 and location of the remediation system.]]
+[[File:PlumeExtent2006-2015.png|thumb|500px| Fig.1: Location of the remediation system and extent of contaminant plume in 2006 and 2015.]]
 === Site history ===
-At the Akacievej site, a dry cleaning facility was operating in the period 1973-2003. In 2002, the site was screened for contamination.
+At the Akacievej site, a dry cleaning facility was operating in the period 1973-2003.
-This revealed high concentrations of PCE and TCE in the pore air close to where a dry cleaning facility operated in the years between 1973 and 1975.
+In 2002, the site was screened for contamination by analyzing the contaminant concentrations in soil and in the pore air.
-Most of the contamination is likely to be from the operation of the dry cleaning facility and a release during a fire at the site in 1975.
+This revealed high concentrations of PCE and TCE close to where dry cleaners were operating in the years between 1973 and 1975.
 The contamination was evaluated to pose a potential risk for the drinking water extraction at the Fløng waterworks, which has its closest extraction well about 600 meters north of the Akacievej site.
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 * Establishment of venting pipes and a drainage pipe
 * Remedial pumping with 2.5 m3/h from the upper 6 meters of the limestone to establish hydraulic control
-* Activated carbon filtering of the pumped water and reinfiltration of the purified water through infiltration cassettes with an overflow connected to a deep borehole
+* Activated carbon filtering of the pumped water and infiltration of the purified water through infiltration cassettes with an overflow connected to a deep borehole
-[[File:Geology_Akacievej_GEO_extended.png|thumb|500px| Fig.3: Geology at the Akacievej site.]]
+Until 2015, a contaminant plume with a length of approximately 500 m had developed.
 === Geology ===
-The geology at the Akacievej site is depicted in Figure 3 and consists of a carbonated sand limestone (København Kalk) on top of a bryozoan limestone (Stevns Klint formation), both with a strongly varying hardness.
+The geology at the Akacievej site is depicted in Figure 2 and consists of a carbonated sand limestone (København Kalk) on top of a bryozoan limestone (Stevns Klint formation), both with a strongly varying hardness.
 Due to glacial activity, the uppermost 1 to 5 meters of the limestone are crushed.
 Most of the crushed limestone is in the carbonated sand limestone, but at some places it also penetrates into the bryozoan limestone.