Initial Characterization and Initial Draining/ Re-infiltration

Transkript

1 Region Midtjylland Initial Characterization and Initial Draining/ Re-infiltration February 2012

2 COWI A/S Parallelvej 2 DK-2800 Kongens Lyngby Denmark Tel Fax Region Midtjylland Initial Characterization and Initial Draining/ Re-infiltration February 2012 Project No. P Document no. 02 Version 02 Date of issue Prepared Checked Approved LRSB, FSP TJR, KIRU, ND, LM KIRU

3 Initial Characterization and Initial Draining/Re-infiltration 1 Table of Contents 1 Introduction 3 2 Characterization activities Pre investigations Extra initial campaign Initial characterization, main campaign 10 3 Results Geology and hydrogeology Groundwater chemistry Soil contamination Groundwater contamination Free phase contamination Contaminant mass in the TTA Contaminant mass above the TTA Conceptual models 30 4 Initial draining and re-infiltration Leak testing Draining Re-infiltration 46 5 Summary and Conclusions 48 6 List of references 50 Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

4 Initial Characterization and Initial Draining/Re-infiltration 2 Table of Appendices Appendix 1.1 Site plan, Overview Appendix 1.2 Site plan, Test Cell 1 Appendix 1.3 Site plan, Test Cell 2, 3 and Test Pipes Appendix 1.4 Sand filter and infiltration wells Appendix 1.5 Site plans with contaminant levels Appendix 2 Borehole logs Appendix 3.1 Analytical results Soil Appendix 3.2 Analytical results Water Appendix 4 Geology Appendix 5 Draining data Appendix 6 Structures of contaminants Appendix 7 3d models of test cells Appendix 8 Analysis of variance Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

5 Initial Characterization and Initial Draining/Re-infiltration 3 Project team 1 Introduction Region Midtjylland has chosen the project team consisting of the companies COWI A/S, Rambøll A/S, Kogsgaard Miljø and Geosyntec Consultants (USA) to perform pilot experiments using the remediation technology in situ alkaline hydrolysis at Groyne 42 (Høfde 42; the Site). Photos from the Site are shown in Figure 1-1. Other sub-consultants involved in the project are the research group CIChem, Aalborg University, Esbjerg, Dr. Kurt Pennell, Tufts University, Medford, Massachusetts, USA, and Dr. Eric T. Vogler, NASUS Water Treatment Technologies, LLC, Bernalillo, New Mexico, USA. The companies Frisesdahl A/S, Jysk GVS and Milana A/S are subcontractors to COWI A/S for the project. Figure 1-1: Photos of the Site. The former chemical dumpsite is located on the beach in Jutland Denmark adjacent to the North Sea. The lower right photo shows the iron sheet piling enclosing the contaminated area. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

6 Initial Characterization and Initial Draining/Re-infiltration 4 Objectives The primary objectives of the NorthPestClean project are: 1. To demonstrate in a large-scale pilot experiment the efficiency of a novel remediation method that uses in situ alkaline hydrolysis to treat pesticide contaminated soil and groundwater. 2. To demonstrate, in side-by-side pilot experiments, the performance and usability of different "enhancement" technologies (i.e., technologies for improving in situ alkaline hydrolysis by enhancing the delivery of hydroxide solution to the target treatment zone and in situ mixing with target contaminants). Project approach The approach of the project is to use large-scale pilot tests to demonstrate and enhance the effectiveness of in situ alkaline hydrolysis at the Site, and to use data collected in these pilot tests to support the design and cost estimation for full-scale in situ alkaline hydrolysis remediation at the Site. The project will be conducted in three test cells and three test pipes located within the sheet-piled area of the Site (i.e., the pilot test area). The target treatment area (TTA) of the test cells/pipes extend from sea level (0.0 m) to the top of a silt layer located at about 3.0 m below sea level. Further details regarding the project approach and are presented in the experimental plan /1/. Pre investigations The final location of the test cells was decided based on the results from preliminary drilling campaigns. The locations were evaluated with respect to amount and distribution of dense non-aqueous phase liquid (DNAPL) in the sand. Initial characterization After determining the final location of the test cells, each test cell and pipe was characterized in detail with respect to geology and contaminant distribution. Initial Draining The pilot test program includes draining of the test cells and Test Pipes 2 and 3 at five points in time as described in /1/. This report describes the results from the pre investigations, the initial characterization of the test cells and pipes, and the initial draining/re-infiltration. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

7 Initial Characterization and Initial Draining/Re-infiltration 5 2 Characterization activities This section describes the field work performed as part of the initial characterization of the test cells and test pipes. 2.1 Pre investigations From the 15 th to the 17 th of March 2011 the first 6 characterization wells were installed in order to give a preliminary assessment of the geology and contamination in the locations proposed for the three test cells. These characterization wells were installed in order to answer the flowing questions concerning the location of the test cells: Are the contaminant distribution and geology comparable for the test cells? Is each cell fairly homogeneous in terms of pollutant distribution? Is the elevation of the silt layer consistent in each test cell? It is of paramount importance that the results of the planned pilot tests can be extrapolated to the total contaminated area and that contaminant distribution and geology are the same in each test cells. The locations of the test cells are expected to represent the most contaminated areas at the Site. Drilling The wells were installed as follows: The auger was advanced to a depth of approximately 20 cm above the water table, and then the auger was pulled up and cleaned of materials. The auger was then lowered into the borehole, and the auger was advanced another approximately 3.0 meters further down in order to reach the planned depth, which was 0.2 m above the top of the silt layer. Next, the auger was slowly pulled approximately 4.5 meters upwards in the borehole and then kept stationary for a few seconds, allowing groundwater to flow from the drilled soil, while the sand layer in the unsaturated zone was supporting both drainage and stability. This approach was intended to minimize the risk of borehole caving and to protect the integrity of soil samples present on the auger flights. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

8 Initial Characterization and Initial Draining/Re-infiltration 6 The auger then was lifted up, while sand and stones from the unsaturated zone continuously were removed. When the intact drilled materials came up above ground level, the soils on the auger were scraped free of residues from adjacent layers, and the intact soils were described for each of the approx. 3.0 drill meters. Soil sampling was carried out for each half meter according to the guidelines in /1/. When the auger was lifted up, the casing was pushed as far down as possible, typically just below the water table. The sand bailer was used to empty the casing, while the casing was pushed continuously approximately half a meter ahead of the sand bailer. When the casing reached the planned depth of 20 cm above the silt layer, the sand bailer was used to complete the emptying of the casing down to this level. A sampling tube was pushed approximately 50 cm down into the bottom of the borehole in an attempt to obtain a precise and intact sample of the silt layer. When the depth to the top of the silt layer was determined, the sand bailer was applied to empty the casing until the depth of the top of the silt layer was reached. When the borehole was complete, three 0.5 m well screens and various bentonite seals were installed. The screens were installed at level -0.5 to m, from top of the silt layer and 0.5 m upwards, and in-between these two. There was a final cleanup around the borehole, and drilled soils were collected in a container. Then the bentonite layer around the borehole was repaired in order to prevent rainwater infiltration. A 12 V submersible water pump was installed and activated in each well screen in order to develop the well (i.e., remove particulates and turbidity remaining in the well screen sand pack after well installation). The pump then was raised and stored in the unsaturated zone after development of the well screen. Using an 8 auger to install the boreholes and wells provided sufficient space for both installing an appropriate spacing between well screens and establishing an effective bentonite seal between the screens. The wells installed during initial characterization were named TC1-3old, TC1-4old, TC2-3, TC2-4, TC3-4 and TC3-9. The locations of the wells are shown in Appendix 1.1 and Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

9 Initial Characterization and Initial Draining/Re-infiltration 7 Figure 2-1: Drilling during the pre-investigation. Soil sampling During drilling, split-spoon core soil samples were obtained every half meter between the elevations of 0.0 m and -2.8 m DVR90 (the observed elevation of top of silt layer). Based on field observations during drilling, additional soil samples were collected at the request of Region Midtjylland. The supplementary samples were typically chosen in order to give a local assessment of the presence of contaminants in layers above an elevation of 0.0 m. In total 65 soil samples were obtained. Approximately 10 subsamples of soil were collected from each 0.5 m core in the split-spoon barrel. The soil in each sub-sample (a total of approx. 50 g) was collected in a 100 ml glass flask. The sample was preserved with 50 ml of a phosphate buffer and 20 ml of toluene and shaken for 30 seconds to extract the compounds to the organic phase and thereby ensure that the hydrolysis reaction in the sample was quenched (i.e., no further hydrolysis could occur in the sample bottle). This preparation in the field further secured preservation of the sample; thus the sample did not need to be analyzed immediately after arrival at the laboratory. Preservation of the samples followed the protocol presented in /1/ except that neutralization was not necessary because ph was already below 7. The following steps summarize the preservation procedure: Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

10 Initial Characterization and Initial Draining/Re-infiltration 8 1. The sample was collected in 100 ml glass with Teflon TM -coated cap. 2. The sample contained approximately 50 g soil consisting of 10 subsamples obtained by sampling by a split-spoon core in order to secure representative sampling. 3. The weight of the sample bottles was measured to the nearest gram in the field. 4. The sample was extracted by adding 50 ml phosphate buffer and 20 ml toluene, and shaking the sample for approximately 30 seconds. At later sample events 30 and 40 ml of toluene was used for extraction to improve the extraction process. All the mentioned soil samples were analyzed by Cheminova s laboratory for organophosphorus pesticides (OPP), tri-esters (TRI) and 4-chloro-creosol (4- Cl-creosol). Molecular structures of the contaminants are found in Appendix 6. Table 2-1: Groups of compounds analyzed.p1 and P2 acids (P1P2) were only analyzed in water samples. OPP TRI P1P2 Ehtyl sulfotep (E-Sulfotep) E-OOOPS MP2-acid Methyl-amoni-parathion (M-Amino-P3) M-OOSPS MP1 Methyl parathion (MP3) EEM-OOSPS Iso-MP1 Malathion E-OOSPS EP2-acid E-amino-parathion (E-Amino-P3) Ethyl parathion (EP3) EP1 Results from the chemical analyses are shown in Appendix 3.1. Groundwater sampling Groundwater samples were collected from the 3 screens in each of the 6 initial characterization wells on 4 April The collection of groundwater samples was carried out using a peristaltic pump. Prior to sample collection, the water table elevation in each well was measured and the water volume calculated. At least three well volumes were purged from each well prior to sampling, and purge flow rate and pumping time were logged. The purged water was discharged to the sand filter and infiltrated in the two infiltration wells that are situated outside the test cells. After purging, a sample was collected from each well screen. In each well an additional sample from the lowest filter screen was collected, which was filtered through a disposable 0.32 micron filter to test if non aqueous phase contamination could be retained by the filters. The samples (approximately 80 ml) were collected in a 100 ml flask and sealed with a Teflon TM cover. Analytical results from filtered and unfiltered samples are presented in Table 2-2. Filtration caused a decreased concentration of EP3, but in the end the filter could not retain droplets of DNAPL (this could be due to oversaturation of the filter). Al- Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

11 Initial Characterization and Initial Draining/Re-infiltration 9 so, concentrations below saturation decreased even further through the filter, which was likely a result of adsorption in the filter. The concentration of the other compounds analyzed were very close to identical in filtered and unfiltered samples and, consequently, filtration was not performed in the following sample campaigns. A photograph of the filtration set-up is provided in Figure 2-2. Results from the chemical analyses are shown in Appendix 3.2. Table 2-2: EP3 concentrations (mg/l) in water in filtered and unfiltered samples. Well screen EP3 conc. (filtered) EP3 conc. (unfiltered) TC1-3old TC1-4old TC TC TC TC Figure 2-2: Groundwater sampling and filtration. 2.2 Extra initial campaign Analytical results for soils collected during installation of the initial characterization wells showed that soils in the proposed location of Test Cell 1 had a significantly lower content of pollutants than expected. On 11April 2011 two supplementary characterization wells were established in order to collect further preliminary assessment of the geology and contamination, and thus compare two different proposed locations for Test Cell 1. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

12 Initial Characterization and Initial Draining/Re-infiltration 10 TC1-9old was placed North of Test Cells 2 and 3, close to the location initially planned for installation of Test Cell 1 (see appendix 1.1). However, the soil samples from this well once again showed no significant signs of contamination from elevation +1 m to -2 m, and therefore it was decided to move the location of Test Cell 1. TC1-7 was placed South of Test Cells 2 and 3 in an area with more contamination and it was decided to establish Test Cell 1 in this location (see Appendix 1.1). Drilling The two wells (TC1-9old and TC1-7) were installed as described in Section 2.1, although TC1-9old was not cleansed with sand bailer etc. TC1-9old was cancelled after the drilling. Soil sampling Soil sampling was carried out as described in Section 2.1. Groundwater sampling Groundwater sampling was carried out as described in Section 2.1. Results from the chemical analyses of soil and groundwater samples are shown in Appendices 3.1 and Initial characterization, main campaign From 30 May until 7 June 2011 the remaining 30 characterization wells were installed in the test cells. Table 2-3 provides a summary of the characterization wells installed in each test cell and test pipe. Table 2-3: Overview of performed wells. Date Test cell Test pipe March Proposed Final Proposed TC1-3old TC1-4old April TC1-9old TC1-7 May & June TC1-1 TC1-2 TC1-3 TC1-4 TC1-5 TC1-6 TC1-8 TC1-9 TC1-10 and final TC2-3 TC2-4 TC2-1 TC2-2 TC2-5 TC2-6 TC2-7 TC2-8 TC2-9 TC2-10 Proposed and final TC3-4 TC3-9 TC3-1 TC3-2 TC3-3 TC3-5 TC3-6 TC3-7 TC3-8 Proposed and final TP1-1 TP1-2 Proposed and final TP2-1 TP2-2 Proposed and final TP3-1 TP3-2 Wells TC1-3old, TC1-4old and TC1-9old were installed at the first proposed location of Test Cell 1, which subsequently was abandoned. TC1-9old was cancelled. Well TC1-10 replaces well TC1-7. Well TC2-10 replaces well TC Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

13 Initial Characterization and Initial Draining/Re-infiltration 11 Drilling The wells were installed as described in Section 2.1, except that soil was collected and described in 1.5 m increments instead of 3.0 m increments. The drilling is shown in Figure 2-1. The locations of the wells are shown in Appendices 1.2 and 1.3. Figure 2-3: Drilling and sampling during the main campaign. Soil sampling Soil sampling was carried out as described in Section 2.1, with the following exceptions: In Test Cell 1 soil samples for each 0.5 m were collected from elevation +1 m down to the silt layer. In Test Cells 2 and 3 soil samples for each 0.5 m were collected from elevation +2 m down to the silt layer. These soil samples were in general analyzed for organic pesticides and related substances. Separate soil samples to be analyzed for mercury were collected as follows: - Soil samples from 4-5 wells in each test cell and both wells in each test pipe were collected. - In each of the selected wells two soil samples, which represent the layers from elevation 0.0 m to -1.5 m and -1.5 m until the top of the silt layer, respectively, were collected. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

14 Initial Characterization and Initial Draining/Re-infiltration 12 - While drilling, split-spoon core soil samples were obtained from each 1.5 meter depth interval. - Furthermore, two supplementary soil samples were collected from a possible old sludge layer, which in general was observed at an elevation of approximately +1 m in all the wells in Test Cell 2 and 3. The soil samples collected for each 0.5 m were analyzed by Cheminova s laboratory for OPPs and TRI, and the approx. 1.5 meters soil samples were analyzed by Milana A/S for mercury. Results from the chemical analyses are shown in Appendix 3.1. Groundwater sampling For the 29 wells in the test cells and the 6 wells in the test pipes, groundwater samples were collected from each of the three screens during the period from June to July On June 24, groundwater samples from screen 1 and 3 in TC1-5, TC2-6, and TC3-6 were collected and analyzed for silicon and main chemical compounds at Milana, see Section 3.2. The collection of groundwater samples was carried out using 12 V peristaltic pumps. Each well screen had its own PE tubing, and the tubing was left hanging above the water table after each water sampling was completed, in order to try to preserve the tubing. In a few of the deep monitoring wells, free phase contamination was observed. Examples of bailed free phase are seen in Figure 2-4. Groundwater sampling was performed as described in Section 2.1. Results from the chemical analyses are shown in Appendix 3.2. Figure 2-4: Examples a free organic phase bailed from monitoring wells. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

15 Initial Characterization and Initial Draining/Re-infiltration 13 3 Results 3.1 Geology and hydrogeology The overall geology of the test cells is described in Table 3-1 to Table 3-3. Additional details are provided in the borehole logs presented in Appendix 2 and in the detailed description of the geology found in Appendix 4. Based on the geological information, geological models were prepared with GeoScene 3D, see Figure 3-3.These models will at a later stage be used for groundwater modeling with FEFLOW. Table 3-1: Test Cell 1 overall geology. Thickness ~Level Description Remarks Meter From To Sand, medium, stony, light gray Locally to level +1.6 (fill) Sand, medium, well sorted, light (fill) In TC1-2 and TC1-8 the light sand layer was not observed. Locally, a few small stones Sand, medium, well sorted, light brown (intact) Sand, medium-coarse, well sorted. Locally fine gravel/pebbles. The color of the layer varies between grey, dark grey, brown and dark brown horizons. The color of the layer varies between grey, dark grey, brown and dark brown horizons Sand, medium, well sorted. The color of the layer varies between grey, dark grey, brown and dark brown horizons Organic silt, silty, green, shells, shell fragments and organic parts Alternating layers of silt and fine sand. Locally medium grained sand. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

16 Initial Characterization and Initial Draining/Re-infiltration 14 Table 3-2: Test Cell 2 overall geology. Thickness ~Level Description Remarks Meter From To Sand, medium, stony, light (fill) Locally to level Sand, medium, well sorted, light (fill) Sequence with well sorted sandy sludge, brown and grey bands (intact) Sand, medium, well sorted, grey/brown Organic silt, silty, green, shells, shell fragments and organic parts Alternating layers of silt and fine sand. Locally medium grained sand. In TC2-8 and TC2-9 faint light/brown horizons were observed. No plant residues, shell fragments, etc. were observed. The color of the layer varies between grey, dark grey, brown and dark brown horizons. Table 3-3: Test Cell 3 overall geology. Thickness Level Description Remarks Meter From To Sand, medium, stony, light (fill). Locally to level Sand, medium, well sorted, light (fill) Sequence with well sorted sandy sludge, brown and grey bands (intact) Sand, medium, well sorted, grey/brown Organic silt, silty, green, shells, shell fragments and organic parts Alternating layers of silt and fine sand. Locally medium grained sand. No plant residues, shell fragments, etc. were observed. The color of the layer varies between grey, dark grey, brown and dark brown horizons. The characterization shows that the geology of the three test cells (and pipes) is relatively uniform to the investigated depth of about 8 m bgs. The geology is characterized by the following layers: Sand, medium, stony fill sand placed as part of coast protection and as part of installation of the sheet piling around the contaminated area. Sand, medium, light/grey, well sorted, placed or deposited after shut down of the waste deposit in February 1962, where the sea burst the Western dike during a storm surge. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

17 Initial Characterization and Initial Draining/Re-infiltration 15 Sand with sludge horizons in Test Cells 2 and 3. This layer is generally believed to have been removed in Test Cell 1 as part the excavation of the waste deposit in Sand, medium, well sorted, intact, locally more fine- or coarse-grained layers, see examples in Figure 3-1. Organic silt (green) and silt (grey). Alternating layers of silt and fine grained sand. Figure 3-1: Shift from medium grained to fine grained sand 6 m bgs in TC1-2 (left) and a 10 cm layer of medium grained sand 7 m bgs in TC1-8. It was estimated that the uncertainty in the depth of the auger was 5-10 cm and the uncertainty of the samples removed from the subsurface was likewise 5-10 cm. This resulted in a maximum error on the reported depths of about ±20 cm. The elevation of the top of the organic silt/silt layer is presented in Figure 3-2. The average elevations for the top of this layer are m, m, m in TC1, TC2, and TC3, respectively. The standard deviation in this elevation within each test cell is 9 cm to 22 cm, and considering the uncertainties mentioned above, the data suggest that the layer is relatively flat in the location of the test cells. In general, the silt layer is located cm deeper in TC1 compared to TC2 and TC3. The elevation of the silt layer of m in TC3 is subject to uncertainty, since this borehole (TC3-9) was one of the first boreholes installed and some problems were encountered in determining the precise elevation of the silt layer. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

18 Initial Characterization and Initial Draining/Re-infiltration 16 TC1 TC2 TC TP1 TP2 TP Figure 3-2: Elevation in m (DVR90) for top of the silt layer. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

19 Initial Characterization and Initial Draining/Re-infiltration 17 TC1 TC2 TC3 Figure 3-3: 3D geological models prepared for the test cells. See more 3D models in Appendix 7. The groundwater elevation in the area, when not manipulated by draining within the sheet piled area, is naturally at >0.0 m. Based on water level measurements during the draining process described in Section 4, the hydraulic conductivities of the sandy layers occurring between an elevation of 0.0 m and the top of the silt layer have been calculated to be m/s for Test Cell 1, m/s for Test Cell 2, and m/s for Test Cell 3. The drainable porosity was estimated to be in Test Cell 1 and 2, and in Test Cell /3/. The lower calculated hydraulic conductivity and drainable porosi- Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

20 Initial Characterization and Initial Draining/Re-infiltration 18 ty in Test Cell 3 could indicate a different geology or presence of higher amounts of free phase contamination in Test Cell Groundwater chemistry The results from the analyses of main chemical compounds performed on groundwater samples from two screens in each test cell are presented in Table 3-4. For most compounds, higher concentrations are found in the lower screens placed just above the silt layer. Most results are comparable in the three test cells, but Test Cell 1 differs a bit from the other test cells, especially regarding concentrations of iron and hydrogen carbonate. The redox conditions are iron reducing and large amounts of sulfate are present. Table 3-4: Results from the analyses of main chemical compounds. Parameter TC1-5-1 TC1-5-3 TC2-6-1 TC2-6-3 TC3-5-1 TC3-5-3 Conductivity ms/m ph ph Ammonium mg/l Nitrite mg/l < <00016 < <0,0016 < < Nitrate mg/l Fluoride mg/l Iron mg/l Manganese mg/l Sodium mg/l Potassium mg/l Calcium mg/l Magnesium mg/l Hydrogen carbonate mg/l < Sulfate mg/l Dry matter mg/l Aggressive carbon dioxide mg/l NVOC mg/l Total phosphorous mg/l Silicon mg/l Total nitrogen mg/l Chloride mg/l Nickel µg/l Soil contamination Soil samples collected during the drilling described in Section 2 were analyzed for OPPs and TRIs by Cheminova s analytical laboratory and selected samples were analyzed for mercury (Hg) by Milana A/S as described in the experimental plan /1/. All analytical results for the soil analyses are included in Appendix 3.1. A few Hg concentrations were estimated for intervals, where no samples were collected. These concentrations are marked in appendix Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

21 Initial Characterization and Initial Draining/Re-infiltration 19 EP3 was selected as the focus contaminant since it is found in the highest concentrations and is the primary compound targeted with the alkaline hydrolysis. Also, the concentration of EP3 generally correlates with the concentration of other contaminants. Examples of correlation are presented in Figure 3-4. EP3 and MP3 EP3 and EEM-OOSPS MP3 [mg/kg] R² = 0,3787 EEM-OOSPS [mg/kg] R² = 0, EP3 [mg/kg] EP3 [mg/kg] Figure 3-4: Examples of correlation between EP3 concentrations and MP3/EEM- OOSPS. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

22 Initial Characterization and Initial Draining/Re-infiltration 20 Average, minimum and maximum concentrations for EP3 in each well (6-7 samples from different depths) are presented in Table 3-5. Table 3-5: EP3 concentrations in the TTA from elevation 0.0 m to just above the silt layer. Average (mg/kg) Min (mg/kg) Max (mg/kg) TC ,265 TC1-2 1, ,936 TC1-3 4, ,644 TC ,020 TC1-5 1, ,611 TC ,014 TC1-8 1, ,954 TC ,102 TC1-10 2, ,980 TC1 average 1,457 TC ,306 TC2-2 2, ,606 TC2-4 2, ,338 TC2-5 1, ,820 TC2-6 1, ,172 TC2-7 3, ,291 TC2-8 1, ,691 TC2-9 4,261 1,961 10,418 TC2-10 1, ,127 TC2 average 2,156 TC3-1 2,714 1,078 5,717 TC3-2 1, ,271 TC3-3 2, ,471 TC3-4 1, ,087 TC3-5 2, ,068 TC3-6 1, ,450 TC3-7 4, ,794 TC ,511 TC3-9 2, ,370 TC3 average 2,146 TP1-1 1, ,750 TP <1 1,730 TP1 average 911 TP ,801 TP TP2 average 382 TP3-1 2,903 1,165 4,639 TP3-2 1, ,991 TP3 average 2,354 A single factor analysis of variance (ANOVA) including all concentrations measured in the TTAs of the three test cells showed that it could not be rejected at a 0.10 level of significance, that the average concentration in the test cells could be identical. The calculations are presented in Appendix 8. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

23 Initial Characterization and Initial Draining/Re-infiltration 21 To get an overview of the vertical distribution of contamination in the soil, EP3 concentrations were plotted as a function of depth in Figure 3-5. The horizontal distribution of contaminants in both soil and groundwater divided into 3 depth intervals are presented in Appendix 1.5. From the results presented in Figure 3-5 it is evident that contamination is spread almost evenly over depth in the TTA. Figure 3-5 also shows that high EP3 concentrations are present from elevation 0.0 m to +1 m above the TTA for all test cells and Test Pipes 2 and 3, but not Test Pipe 1. In addition, the data indicate that the degree of contamination in TP1 is low compared to the other test cells/pipes. Figure 3-5: EP3 concentrations as a function of depth in the test cells and pipes. The TTA from elevation 0.0 m to top of the silt layer is marked with orange Mercury concentrations in the soil are presented in Figure 3-6. It is noted that very high mercury concentrations ( mg/kg, not included in Figure 3-6) were observed in the sludge layer in Test Cell 2 at an elevation of +1 m (in the unsaturated zone). In general, mercury in the unsaturated zone is not expected to influence the pilot test because NaOH will only be filled to an elevation of 0.0 m. However, if the injected NaOH comes into contact with layers above an elevation of 0.0 m, mercury mobilization from the unsaturated zone could occur. It is noted that high concentrations of OPP contamination exist in the unsaturated zone as indicated by Figure 3-5. The mercury concentrations in Test Pipes 1 and 2 were low (4-60 mg/kg). Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

24 Initial Characterization and Initial Draining/Re-infiltration 22 Figure 3-6: Hg concentrations as a function of depth in the test cells and test pipes. The TTA from elevation 0.0 m to top of the silt layer is marked with orange. Note the different scale for the test pipes. 3.4 Groundwater contamination Collected groundwater samples were analyzed for OPP, TRI, P1/P2 acids (P1P2), and para-nitrophenol (PNP) by Cheminova s analytical laboratory and ph was measured in the field during sample collection. The specific compounds quantified in the analyses are presented in Table 2-1. All analytical results for the water analyses are included in Appendix 3.2. Average concentrations and ph in each test cell/pipe is presented in Table 3-6. ph varied widely within each test cell/pipe both horizontally and vertically, see more details in Appendix 3.2. The ph of Test Cell 1 (ph ) is different from the Test Cells 2 and 3 (ph ). An ANOVA proved that ph was significantly (α=0.10) different in TC1 (p value ), whereas it could not be rejected that the ph in TC2 and TC3 are equal. No significant (α=0.10) vertical differences in ph could only be observed in TC1 and TC2. ANOVA showed that the ph was significantly (α=0.10) higher in the layer represented by the upper screens placed from -0.5 to -1.0 m. All results from the ANOVA are presented in Appendix 8. It is evident that the group of water soluble hydrolysis products (P1 and P2 acids) is found in the highest concentrations. Concentrations vary greatly within each test cell/pipe. Horizontal and vertical variations are presented in the site Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

25 Initial Characterization and Initial Draining/Re-infiltration 23 plans found in Appendix 1.5. Detailed overview of contaminant concentrations and ph in each test cell divided into three horizontal layers, where each screen represents a layer, are presented in Tables 3-7, 3-8 and 3-9. ANOVA showed that the concentration of EP2 acid is significantly (α=0.10) different in all three test cells, with the highest concentration in TC1 and the lowest concentration in TC2. The analysis also showed that the concentration of EP2 acid increases significantly (α=0.10) with depth from the medium screens to the deep screens in all test cells. All results from the ANOVA are found in Appendix 8. Table 3-6: Simple overview of average concentrations and ph in the groundwater. TC1 TC2 TC3 TP1 TP2 TP3 ph ,9 2,8 3,6 OPP, sum (mg/l) TRI, sum (mg/l) P1P2, sum (mg/l) PNP (mg/l) Table 3-7: Detailed overview of concentrations (mg/l) and ph in Test Cell 1. TC1 Elevation -2 m to top of silt -1 m to -2 m 0 m to -1 m Average Std dev. Average Std dev. Average Std dev. ph E-OOOPS M-OOSPS EEM-OOSPS E-OOSPS Chlorcresol MCPA <1 E-Sulfotep M-Amino-P MP Malathion E-Amino-P EP PNF MP2-acid MP Iso-MP EP2-acid EP Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

26 Initial Characterization and Initial Draining/Re-infiltration 24 Table 3-8: Detailed overview of concentrations (mg/l) and ph in Test Cell 2. TC2 Elevation -2 m to top of silt -1 m to -2 m 0 m to -1 m Average Std dev. Average Std dev. Average Std dev. ph E-OOOPS M-OOSPS EEM-OOSPS E-OOSPS Chlorcresol MCPA < E-Sulfotep M-Amino-P MP Malathion E-Amino-P EP PNF MP2-acid MP Iso-MP1 1.4 <1 <1 EP2-acid EP1 <1 <1 <1 Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

27 Initial Characterization and Initial Draining/Re-infiltration 25 Table 3-9: Detailed overview of concentrations (mg/l) and ph in Test Cell 3. TC3 Elevation -2 m to top of silt -1 m to -2 m 0 m to -1 m Average Std dev. Average Std dev. Average Std dev. ph E-OOOPS M-OOSPS EEM-OOSPS E-OOSPS Chlorcresol MCPA E-Sulfotep M-Amino-P MP Malathion E-Amino-P EP PNF MP2-acid MP Iso-MP <1 EP2-acid EP1 < <1 3.5 Free phase contamination During the drilling campaigns mobile free phase (dark NAPL flowing freely from the soil sample) was observed on top of the silt layer in the following boreholes: TC1-5, TC1-6 and TC1-10 TC2-2, TC2-8 and TC2-10 TC3-2, TC3-3, TC3-5and TC3-7 TP1-2 Thus the presence of free mobile organic phase was observed on top of the silt layer in approximately every 3 rd well in the test cells. In addition, residual free phase (dark NAPL not flowing freely from the soil sample) was observed in the in the following boreholes: A 2-3 mm horizon in the upper part of a layer containing fine grained sand in TC Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

28 Initial Characterization and Initial Draining/Re-infiltration 26 A narrow horizon (a few mm thick) on top of a sandy layer in TC2-2, which locally contains natural organic matter (i.e. plant residues) and silt/clay. A 4-5 mm horizon in well TC3-1 on top of a silty sand layer. The field observations indicate that the presence of free mobile and residual organic phase was dictated by the presence of layers with low hydraulic permeability. Examples of free phase observations are depicted in Figure 3-7. In general, these findings are consistent with the expectations. It should be noted that no correlation could be observed between the presence of free phase and the concentrations measured in the soil. During the initial water sampling signs of free phase contamination was observed in the deep screens of monitoring wells TC2-6, TC3-7, and TC3-9. Figure 3-7: Free phase on top of a narrow fine-grained horizon in TC2-4 (left) and free phase in TC3-5 on top of the organic silt (right). 3.6 Contaminant mass in the TTA Calculations were carried out for soil and groundwater to estimate the total contaminant mass. The calculations for the test cells/pipes were based upon the results from soil and water samples collected and analyzed from the characterization wells. Mass in Soil The total mass of selected contaminants in soil was calculated for the saturated zone thickness extending from elevation 0.0 m down to the top of the silt layer. In each test cell, 9 wells have been installed and typically 7 soil samples were collected from the TTA, which corresponds to more than 60 samples in total for each test cell. The water saturated volume was up to 280 m 3 (about 500 ton). This corresponds to one analysis for every 8 ton of soil. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

29 Initial Characterization and Initial Draining/Re-infiltration 27 The calculations of contaminant mass in the soil were based on the following principle: The test cell is divided into 9 sub-cells (11.1 m 2 each), equaling 1 well in each sub-cell. Vertically, the cell is divided into layers representing each sample interval, typically 0.5 m. For each interval in all sub-cells the volume and mass of soil was calculated. The density of the wet soil was assumed to be 1800 kg/m 3. The total mass in each test cell was found by summing the masses of the individual sub-cells. All calculations and results are presented in Appendix 3.1. The same procedure was followed for the test pipes. This method is believed to give a reasonable calculation of the contaminant mass. It is noted that the calculation of mass in soil includes both sorbed contaminants and non-aqueous phase liquid (NAPL) since data do not exists to distinguish between free phase and sorbed phase contaminant. The largest uncertainty is the presence of free phase. Dissolved phase mass Dissolved phase contaminant mass occurring in the groundwater between an elevation of 0.0 m and top of the silt layer were also calculated. The calculation of contaminant mass in the groundwater was based on the following principle: Horizontally, each test cell is divided into 9 sub-cells (11.1 m 2 each), equaling 1 well in each sub-cell. Vertically, each sub-cell is equally divided into 3, equaling 1 screen for each resulting in a total of 27 sub-volumes. Contaminant mass in each of the 27 sub-volumes was calculated based on measured contaminant concentrations and an assumed total porosity of 45%, which should be distinguished from the effective and drainable porosity. All calculations and results are present in Appendix 3.2. Same procedure was followed for the test pipes. Results The calculated contaminant masses in each test cell/pipe for selected contaminants are presented in Table 3-10 for soil and Table 3-11 for groundwater. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

30 Initial Characterization and Initial Draining/Re-infiltration 28 Table 3-10: Total masses (kg) of contaminants in the soil (sorbed + free phase) in each test cell/pipe. TC1 TC2 TC3 TP1 TP2 TP3 E-OOOPS M-OOSPS EEM-OOSPS E-OOSPS Cl-Cresol E-Sulfotep M-Amino-P MP Malathion E-Amino-P EP Hg Table 3-11: Total masses (g) of dissolved phase contaminants in each test cell/pipe. TC1 TC2 TC3 TP1 TP2 TP3 E-OOOPS , M-OOSPS 1,580 2,000 1, EEM-OOSPS 990 1,000 1, E-OOSPS Cl-Cresol MCPA , E-Sulfotep M-Amino-P MP Malathion E-Amino-P EP , PNF 2,140 1,990 3, MP2-acid 5,900 2,020 4, MP1 4, , Iso-MP1 2, EP2-acid 11,660 2,050 6, EP1 3, A new ANVOVA was performed to evaluate if the calculated masses in the test cells are statistically different. This time the masses calculated for each of the 27 sub cells were used in the calculation. This might improve the result from the ANOVA performed on the concentrations of EP3 in the soil performed in Section 3.3, since this new calculation used weighted values based on different sample intervals. The small difference in height of the TTA in the test cells represents a small error in the calculation. The results showed TC1 vs. TC2 (p value =0.08), TC2 vs. TC3 (p value 0.26) and TC1 vs. TC3 (p values = 0.24). Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

31 Initial Characterization and Initial Draining/Re-infiltration 29 From this it can be concluded that at the 0.10 level of significance only the masses in TC1 and TC2 can be assumed to be different, with the highest mass in TC2 and the lowest mass in TC1. More results from the ANOVA are found in Appendix 8. When comparing the masses in water and soil, it is seen that about 99.7 % of the EP3 mass is found in the soil (no attempts were made to quantify the distribution between sorbed and free phase contamination). For the other compounds it is typically more than 97 %. This distribution is consistent with expectations because of the low solubility of the compounds. Based on previous investigation and measured concentrations of EP3 in the soil at an area of the Site close to the location of the new test cells, it was expected that each test cell would contain about 1,050 kg EP3 in the TTA from elevation 0.0 m to - 3 m. The results from the present investigation are close to the expected, but especially in Test Cell 1, the mass is less than expected. 3.7 Contaminant mass above the TTA The investigation also provided data on the contaminant distribution and concentrations above the TTA. In this section the contaminant mass above elevation 0.0 m (untreated zone of layer 3) and in the sludge layer (layer 2) will be reviewed. Since no sludge layer was observed in Test Cell 1, the contaminant mass was calculated from elevation 0.0 m to +1.0 m. Calculations are performed as described in Section 3.6 and detailed results are found in Appendix 3.1. An overview of the results is presented in Table It is seen the 30%- 50% of the contaminant mass is found above elevation 0.0 m (above the TTA). Table 3-12: Contaminant masses (kg) in each test cell divided into TTA, from TTA to the sludge layer, and in the sludge layer.*no data TC1 TC2 TC3 TTA 0.0m to1.0m TTA 0.0m to sludge sludge TTA 0.0m to sludge 0.0m to sludge Soil volume (m 3 ) E-OOOPS (kg) M-OOSPS (kg) EEM-OOSPS (kg) E-OOSPS (kg) Cl-Cresol (kg) E-Sulfotep (kg) M-Amino-P3 (kg) MP3 (kg) Malathion (kg) E-Amino-P3 (kg) EP3 (kg) Mercury (kg) 89 * 101 * * * Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx

32 Initial Characterization and Initial Draining/Re-infiltration 30 Only two samples from above the TTAs were analyzed for mercury. Both samples were collected from the sludge layer in Test Cell 2 (borehole TC2-1 and TC2-6). The concentrations were 4,900 and 2,600 mg/kg and the dry matter content was 86%. With an estimated volume of 28 m 3 and a density of 1800 kg/m 3 wet soil, the total mass in the sludge layer in Test Cell 2 is 163 kg. This very high content will likely affect the design of a full scale remediation. 3.8 Conceptual models Updated conceptual models for the three test cells are presented in Figure 3-8 to Figure The models are constructed with four different layers; Fill consisting of clean medium grained sand (Layer 1), sludge (Layer 2), contaminated medium grained sand (Layer 3), and organic silt and silt (Layer 4). The layers represent the major geological layers described in Section 3.1. The most important differences are the absence of a sludge layer (Layer 2) in Test Cell 1, a very low calculated drainable porosity in Test Cell 3, and lower contaminant mass in the TTA in Test Cell 1. Hydraulic conductivity (K) and drainable porosity were calculated based on measured changes in groundwater levels during draining of the test cells /3/. The expected drainable volumes shown in the models are calculated from the drainable porosity and the volume of the TTA. Figure 3-8: Conceptual model for Test Cell 1. Project documents/indledende karakterisering/report initial characterization/initial characterization final.docx