1 REMEDIATION OF BRINE-IMPACTED SOIL: EVALUATION OF SEVERAL PERFORMANCE ENHANCEMENTS COUPLED WITH A LEACHATE COLLECTION SYSTEM JOHN N. VEENSTRA AND ROBERT W. WARDEN, OKLAHOMA STATE UNIVERSITY, STILLWATER, OK: THOMAS M. HARRIS, UNIVERSITY OF TULSA, TULSA, OK ABSTRACT Brine-impacted soil poses several environmental problems. High salinity in soil inhibits plant growth, resulting in erosion. The secondary contamination of surface and ground waters by surface runoff and leaching is also a major concern. Currently, many brineimpacted soil remediation techniques exacerbate secondary contamination as they increase the hydraulic conductivity of soils. These methods rely on leaching of salt deeper into the soil instead of its removal. A leachate collection system (LCS) collects the leachate for disposal and ultimate removal of salt from the soil. Several potential performance enhancements were investigated on a field scale both in a historic and contemporary spill in northern Oklahoma for approximately one year. These enhancements included installation of collection system piping in gravel filled trenches to increase the collection rate of the leachate in the contemporary spill, and a drained limestone gravel layer to protect a fresh imported topsoil layer in the historic spill. In both the historic and contemporary spill, elemental sulfur was added to the limestone gravel to biostimulate sulfur oxidizing bacteria to enhance the dissolution of the limestone gravel, providing available calcium in solution for sodium ion exchange on the clay soil particles. Effectiveness of the enhancements was evaluated by analysis of salt concentration in soils, soil permeability, and bacterial plate counts.
2 INTRODUCTION Oilfield brine impacted soils are the legacy of accidental spill or purposeful disposal of water produced during oil production. The problem is common wherever oil is produced. Spilled brine causes the death of the plants supported by the soil leading to increased erosion and eventual loss of the topsoil. Further ramifications are long-term soil productivity loss, spread of saline conditions in the soil, contamination of surface water, the displacement of minerals usually attached to clay particles by sodium ions resulting in poor structure, and reduced permeability to water (1). Current remediation techniques include treatments that enhance the soils fertility and permeability through adding amendments (2). The success of these treatments is dependent on the ability of the water to permeate into the subsurface, carrying salt with it. Naturally, these treatments will be unsuitable for areas where valuable ground water resources would be threatened and unsuccessful where the salt would be unable to migrate downward due to an impermeable layer (3). A leachate collection system (LCS) addresses the issue of contamination of ground water by collecting and directing the soil water leachate to a collection point for disposal. In Area 1 of the test site (Figure 1), the contemporary spill, a 250 gallon fiberglass collection tank with a lid was installed to collect leachate from Area 1. For Area 2, the historic spill, the leachate was collected in a 9000 ft 2 evaporation pond, approximately 3 feet in depth, lined with 60 mil black flexible polyethylene (HDPE) geotextile with a 10-7 cm/sec permeability (Figure 2). The Area 1 (contemporary spill) test site for this project included test cells with several configurations to enhance leaching performance and displacement of sodium ions on the soil with calcium: 1) The addition of limestone gravel was intended to enhance leaching performance by preventing displaced soil fines from collecting in the LCS and to provide calcium to transfer to the soil resulting in the displacement of the monovalent sodium ion responsible for reduced permeability (4); and 2) Elemental sulfur was added to the limestone gravel to determine if the oxidation of elemental sulfur by sulfur oxidizing bacteria to sulfuric acid would dissolve the calcium carbonate in the gravel to calcium sulfate, a more soluble form of calcium. The hypothesis was that the soluble calcium sulfate would travel in solution and displace the permeability reducing sodium ions on the clay particles as a result of brine contamination. The ion concentrations in the soil, changes in the population of aerobic bacteria, and the permeability of soil cores taken from the various test cells were analyzed to evaluate the performance of the leachate collection system and the effectiveness of the enhancements.
3 LABORATORY METHODOLOGY This study involved the analysis of soil for permeability, ion concentration, and aerobic bacterial population. Soil permeability of cores taken from site were determined using ASTM method D-2434 (5), soil ion concentrations were determined by Atomic Absorption Spectrometry (AAS) (6) and Ion Chromotography (IC). Aerobic bacteria populations were determined using plate counts prepared with media for heterotrophic bacteria (7). Soil Extraction Soil extraction techniques were based on methodology utilized by several sources (8, 9, 10). The analysis of soil ion concentration began with the extraction of soluble ions in the soil using high purity water. To prepare the soil extraction, 25 g of soil that has been oven dried for at least 12 hours at 115 F was weighed and 250 ml of high purity 18 MΩ water, produced with a NANOpure Diamond Analytical ultra pure water system, Series 1190 (Barnstead Thermolyne), was added. The mixture was stirred with a dry, clean glass rod and was allowed to stand for a minimum of 4 hours at room temperature, and sequentially vacuum filtered using dry glassware and filtering apparatus and Metriguard qualitative glass fiber filter paper with 0.8 µm pore size (Gelman Sciences), and a GN µm pore size Metricel Membrane Filter (Gelman Sciences). A 1:1 water to soil ratio was the recommended extraction preparation ratio (8). Given the soil being analyzed and the filtering requirements needed by instruments being used to analyze the extract, several problems were encountered. First, a large amount of soil was needed to produce enough extract to be analyzed several times by two different instruments. Second, it was necessary to filter all samples to remove particles larger than 0.45 µm. This proved very difficult when starting with a very turbid extract taken from the typical 1:1 soil extraction. These difficulties were addressed by increasing the ratio of water to soil to 10:1. This allowed for a volume of water to be filtered that had been settled and the turbidity reduced. This procedure produced ample sample volumes and compensation for a 10:1 dilution factor was made when relating solution concentrations to soil concentrations. A portion of some of the soil samples was also prepared using a 1:1 ratio for comparison (9). This extraction procedure partitions only the highly soluble cations and anions into solution. This procedure was not assumed to produce quantitative values for all concentrations of cations and anions in the soil. However, only those ions easily dissolving into water were of concern in this study. Sample Solution Analysis Chloride and sulfate anion concentrations were determined using a Model DX- 120 (Dionex Corp.) ion chromatograph equipped with a 25 µl sample loop, and an IonPac AS14 Analytical (4X250 mm) column (Dionex Corp.) using a 3.5 mm sodium carbonate/ 1.0 mm bicarbonate buffer solution. Each run on the ion chromatograph included a 7- point non-linear calibration increasing in concentration with 250 mg/l chloride and sulfate as the maximum concentrations. Standard solutions were prepared from reagent grade salts and periodically checked with commercially prepared reference standard solutions (Dionex Corp.).
4 Analysis of the calcium, magnesium, and sodium cations were determined by analyzing the extract solution with an AAnalyst 300 Atomic Absorption Spectrometer (Perkin-Elmer Corp) using the flame technique with air/acetylene. All standards were prepared using commercial reference standard solutions (Fisher Scientific). Initially, all samples were run without dilution. Samples registering outside the calibration range were diluted 10:1 and re-run. Additional dilutions were performed until all samples were represented inside the calibration range. Check standards were run every twenty samples (consisting of 10 samples and their duplicate), and the instrument was recalibrated as necessary. All blanks for analysis matched the matrix of the calibration standards. Calcium and magnesium were determined using absorption mode, and sodium was determined with emission mode on the AAnalyst 300. Calcium was analyzed using a 400 mg/l Ca in 2% HNO 3 as the maximum of three standards. Magnesium was run with 15 mg/l Mg in 2% HNO 3 as the maximum of a four point calibration procedure and sodium concentrations were determined using 500 mg/l Na with only 18 MΩ water for the solvent as the maximum of a seven point calibration. All three metals were analyzed using a non-linear calibration procedure (6). Soil Microbiology Soil samples were taken from the field aseptically using two techniques: 1) Coring was performed using a stainless steel coring device that was manually cleaned to be free of dirt and debris then it was rinsed ethyl alcohol, silicone lubricant from an aerosol can was applied and rinsed with sterile water. Rinseate from the instrument was taken from the runoff from distilled, sterilized water sprayed into the barrel using a squirt bottle. The rinseate was collected in vials for future culturing; 2) Trowel soil samples were collected using an auger to determine the approximate soil/gravel interface depth (by augering to gravel). Near the auger hole, a shovel was used to create a large enough opening and of sufficient depth to get close to the depth of the interface of soil and gravel (within about 1-2 inches). Then a sterilized trowel was used to approach the interface (within 1 inch). Finally, sterilized metal spoons were used to collect the actual soil sample. Each soil sample was stored in a new zip-loc bag. A different spoon was used for each duplicate in each cell. Sterile, TGY (Tryptone, Glucose, Yeast extract medium) agar plates (100 X 15 mm) (Fisher Scientific)(11) were prepared. Next, the soil bacteria extractions were performed by aseptically adding 10 grams of soil to an autoclaved 250 ml Erlenmeyer flask containing 100 ml of sterile sodium pyrophosphate solution (0.2% solution). Transfers of material between containers were performed using aseptic techniques. Soil taken from cores was selected from the center of aseptically dissected cores. Once soil was selected and removed from the cores, it was treated as a loose soil sample. Loose soil samples were transferred and weighed using sterilized instruments. The soil bacteria extraction was done as quickly as possible once the soil and sodium pyrophosphate solution were combined, using the procedure described as follows. The covered flask was shaken on a rotational shaker at 200 rpm for 30 minutes. Serial dilutions were prepared by adding 0.1 µl of the previous dilution to 0.9 µl of sterilized 0.9% NaCl solution in an array of 1.5 µl labeled eppendorf microcentrifuge tubes. After serial dilutions from 10-2 to 10-7 were prepared, 0.1 µl of each dilution was plated and spread with a sterile spreader (7). All dilutions, plate preparations, plating, and spreading occurred in a laminar flow
5 hood with a pathogen filter. All sterilization of liquids were performed in a Sterilmatic Sterilizer Model STM-E Type C autoclave (Market Forge) set for 250 F, 15 psi, for 15 minutes. The plates were stored at room temperature for 72 hours and counts were performed. Plates containing between 30 and 300 CFUs were included in calculating the geometric mean of the population indicated by the dilution corrected plate counts. Reported plate counts are averages of duplicate plates, multiplied to account for the dilution factor. Calculations were performed to convert the data to units of CFU per gram of soil. The moisture content of the soil samples were included in the calculations for CFU per gram of soil to adjust the data to dry basis (CFU per gram of dry soil). Soil Permeability Permeability tests were performed according to ASTM method D-2434 (5). Soil cores were carefully shaved to a diameter slightly larger that the permeameter mold. Silicone vacuum grease was applied to the walls of the permeameter mold, and its weight was recorded. The shaved soil core was carefully inserted into the permeameter mold; excess diameter was shaved piecewise as the core was inserted. After the soil core was inserted, porous stones were inserted in the ends and the core was shaved on the ends accordingly to fit the needed stones. After the sample was inserted, fit, and sized, the porous stones were removed and the permeameter mold and soil test core weight was recorded. After weighing, the porous stones were re-inserted, and the permeameter mold was installed on the permeameter manifold. Tap water was used to test the cores. After degassing the top of the permeameter mold, the test was started. A large number of the cores were tested at 2, 4, and 10 psi, which correspond to 140.6, 281.2, and 1406 cm of head, and hydraulic gradients of 22, 44, and 110 respectively. Operation of LCS RESULTS AND DISCUSSION During the course of this study, the Area 1 collection tank installed for collecting the leachate from the LCS flooded several times because of heavy rains. This resulted in leachate backing up into the LCS, preventing proper collection of leachate samples. Also, after draining the LCS during a winter sampling event, the empty collection tank floated due to buoyancy caused by saturated soil. It was hypothesized that the installation of the LCS would increase the permeability of the soil by increasing the leaching of ions associated with brine out of the soil. The leaching of the ions that reduce permeability of the soil, specifically sodium, was hypothesized to be enhanced by the potential increased mobilization of calcium through bio-stimulation of sulfur-oxidizing bacteria. This enhancement was based on the production sulfuric acid by sulfur oxidizing bacteria (12) according to the following reactions: 2S + 3O 2 + 2H 2 O 2H 2 SO 4
6 It was believed that the production of sulfuric acid would promote dissolution of the calcium carbonate in the gravel and its mobilization in the aqueous phase. Calcium (Ca 2+) would then be available to displace the sodium (Na + ) on the clay particles. It was intended that a primary measurement in this study would be the composition of the leachate from the LCS over time. Observed changes in ion concentrations in the leachate from individual test cells would indicate what was being leached out of the soil and if the gravel and sulfur enhancements were having any affect. One factor that prevented these observations was that there was little or no leachate to collect during sampling trips. This was likely due to the low permeability of the soil and delay of the leachate traveling to the LCS after a precipitation event (as can be seen from the permeability tests). Soil Permeability Permeability tests were performed according to ASTM method D-2434 (5). It was hoped that testing the soil permeability would yield some data to quantify the effectiveness of the removal of the sodium ions from the soil. However, soil conditions at the site were highly heterogeneous, and many of the samples disintegrated during the permeameter mold core preparations. What permeability data was collected could be grouped with respect to area and the core permeabilites were graphed with respect to date of sample collected (Figure 3). Data illustrated in Figure 3 is the average of all permeabilities of soil cores taken from Area 1. The Area 2 gravel protected imported topsoil layer permeability was not relevant to this portion of the study. It was not possible to show permeability changes by cell because of the relatively few data points gained from the soil cores that survived the preparation for the test. Overall background permeability represents the permeability of the soil in the unaffected area surrounding both Areas 1 and 2. Area 1 background permeability represents the permeability of samples taken from the unaffected areas immediately adjacent to the Area 1 test cells. Notice that the background permeability of Area 1 and the overall background of the project site are very close (K overall background = 6.9E-07 cm/sec, K area 1 background = 7.5E-07 cm/sec). This background permeability for the test area and the unaffected areas was determined from samples locations designated in Figure 4, which shows the sampling regime with the experimental Area 1 overlaid. Area 1 11/18/00 represents the permeability of samples taken from cells 7, 8, 9, and 10 on this date. Of the three cores that could be tested for permeability, data could not be collected on one of them because there was no breakthrough after several weeks of testing. The remaining data was combined and averaged and permeability for those cells was 1.01E-07 cm/s. This represents data taken after 2 months from the start date of the project (September 15, 2000), and there had been significant precipitation by that time to transport ions into the LCS (Figure 5) (13). All data were from cells that had an LCS drainage pipe installed. The average of the permeabilities represented by Area 1 7/10/01 includes the permeability of the same cells (7, 8, 9, and 10) after 10 months of operation. The increase in permeability from the November 2000 sampling event to July 2001 could be misleading since the graph is based on so few sample cores. This permeability trend does not correspond to the decrease of soil ion concentrations (particularly sodium) as seen in Figure 6 for which there is ample data. It was hypothesized that when sodium shows its lowest concentration, permeability would be at its highest. This ion concentration trend was also observed with all other ions (Figure 8, Figure 9, Figure 10) except calcium (Figure 7), which might possibly be explained by the hypothesized dissolution of limestone gravel into the soil solution. Since so many of the cores collected did not stay
7 intact enough to be tested some cells only had one data point, and considering the heterogeneity of the site, this was not enough information to compare changes in permeability by cell. Therefore, the data is inconclusive as to the relative effectiveness of the various individual enhancements. However, it seems to show that even though a significant percentage (20% or more) of the salt was removed (Figure 11)), permeability did not seem to change that much. This conclusion might change if more of the Area 1 11/18/00 and Area 1 7/10/01 samples had survived to be tested. Since this was just an indicator test, the ion concentration of the soil was the direct measurement used to make conclusions. Soil Microbiology It was observed that in every cell, the bacterial population counts were lower in July 2001 (Figure 12). This decrease in bacterial population during the July sampling event could be related to the higher ion concentrations and drier conditions that result in less favorable conditions for heterotropic soil bacteria. The highest bacteria populations were from the November 2000 sampling, when the soils were moist and ion concentrations of the soil were nearest to the concentrations found in unimpacted soils. It was found in both sampling events that the sulfur-amended soils did exhibit a slightly higher population count in Area 1(Figure 13, Figure 14). The Area 1 data included cells 7 and 8 (non-amended) and Cells 9 and 10 (amended). In Area 2, it was found that in November, the non-amended Northeast (NE) cell showed the highest bacterial population. In July of 2001, the amended Northwest (NW) cell had the greatest bacterial population and the difference between the amended and non-amended cells had increased (Figure 15). Soil Ion Concentration All ions exhibited the same concentration trend in Area 1 soil with respect to time, highest on the first sampling event, lowest during the November 2000 sampling, and showing an increase during the July 2001 sampling (Figure 6, Figure 7, Figure 8, and Figure 9). Data labeled (UT) was obtained from the University of Tulsa (15). The data obtained from University of Tulsa was obtained during sampling dates occurring in the gaps between OSU sampling dates. Although the University of Tulsa soil analysis was performed using a 1:1 saturated paste soil extract, and ICP-AES was used to analyze for metals, the data exhibited the same general trend of decreasing ion concentrations in the winter with resurgence of ions in the beginning of summer. In all cases, except calcium, the increase in soil ion concentrations between November 2000 and July 2001 never approached the soil ion concentrations present at startup (Figure 6, Figure 7, Figure 8, Figure 9, Figure 10). Calcium concentration exhibited a steady increase with the expected low values during November (Figure 7). This suggests that calcium is becoming more available in the soil solution as a result of the installation of limestone gravel. The magnesium concentration labeled 5/8/2001 (UT) in Figure 8 shows a dramatic increase from the 1/21/01 (UT) sampling event, decreasing to the 21.7 mg/kg soil value determined during the 7/12/01 sampling event. It was observed that the Cell 7 value in the UT data set was nearly twice any of the soil concentration values. If this value was anomalous and excluded, the soil magnesium concentration for the 5/8/2001 (UT) sampling event would indicate very little change from 5/8/01 to 7/12/01. Percent reductions in each ion measured in Area 1 soil can be seen in Figure 11. The negative
8 value for the calcium bar represents the hypothesized increase in the soil concentration of calcium. The LCS performance should not be based on the reduction in ion concentration observed in the November 2000 sampling. The resurgence of ions during the drier part of the year into the upper soil layers has been documented in several remediation projects (8,14) and is a better reflection of the degree to which the LCS was effective. Temperature and precipitation data taken from Oklahoma Mesonet Station #32 in Copan, OK (12.9 miles north of Bartlesville, OK) (Figure 16) reports relatively low precipitation and dramatically increasing temperatures in the three months prior to the July 2001 sampling event (Figure 17). Soil temperatures with respect to time are illustrated in Figure 18 along with temperature and precipitation. In addition, it was observed that a 20% or greater removal of ions possibly occurred over the year, except in the case of calcium, which exhibited an increase in concentration. Observations with regards to the effects of the LCS compared to natural processes were difficult to discern. The first sampling event in July 1999, indicates the highest soil ion concentrations, except in the case of calcium which increased in concentration from project start up. Sulfate, sodium, and chloride ions exhibit 52.5%, 48.1%, and 11.2% decreases respectively between the 7/20/99 and the 9/24/00 (UT) data set, which was immediately after the installation and is believed to be representative of the soil concentrations at the startup of the LCS due to insignificant precipitation since the 9/15/00 installation (Figure 19). The decrease in soil ion concentrations between the 7/20/99 and 9/24/00 (UT) data sets is believed to be a manifestation of the pulsing effect of the soil ions between wet and dry periods and not the installation of the LCS. However, after a period of time, it remains difficult to quantify the simultaneous effects of natural processes and the LCS in this situation. It has been shown that there is a natural pulsing of the soil ion concentrations that is a function of precipitation. It is difficult to determine where in the pulse the data occurs, however, it is believed that an insignificant amount of salt left the soil between 7/20/99 and 9/24/00 due to natural leaching and the observed difference is due to sampling occurring at different places on the pulse of soil ion concentrations at the sampling depth. Since July is characteristically the driest part of the year of in Oklahoma, it is believed that the 7/20/99 and 7/12/01 data represents the maximum surface soil ion concentrations for that year and that this will be a valid measuring point to determine the effects of the LCS and the various enhancements, therefore percent reductions were calculated using these two data sets. Other reasons for decreases in sulfate soil ion concentration other than leaching include its assimilation into biomass and combination into less soluble forms (12). Sodium and chloride are highly soluble monovalent ions and are therefore exceptionally mobile in the soil solution, resulting in large variations in the concentrations of these particular ions with or without the installation of an LCS. SUMMARY AND CONCLUSIONS A leachate collection system (LCS) collects the leachate for disposal and ultimate removal of salt from soil was demonstrated on a test site 3 miles east of Bartlesville, OK. Several potential performance enhancements were investigated on a field scale in both a contemporary spill (Area 1) and a historic (Area 2) in northeastern Oklahoma for approximately one year. These enhancements included installation of collection system piping in gravel filled trenches to increase the collection rate of the leachate in the contemporary spill, and a drained limestone gravel layer to protect a fresh imported
9 topsoil layer in the historic spill. In both the historic and contemporary spill, elemental sulfur was added to the limestone gravel to biostimulate sulfur oxidizing bacteria to enhance the dissolution of the limestone gravel, providing available calcium in solution for sodium ion exchange on the clay soil particles. Effectiveness of the enhancements was evaluated by analysis of salt concentration in soils, soil permeability, and bacterial plate counts. Permeability tests on the soil were inconclusive. A large portion of summer samples did not survive the permeability test preparations and of those that survived, many of those were impermeable. The remaining samples provided enough data to view Area 1 (the contemporary spill) as a whole, without differentiating between cells and the effectiveness of various enhancements. Soil ion concentrations did evidence percent reductions ranging from 26.6% to 53.6%, except for calcium, which exhibited an approximately 44% increase over the year. It is believed that this is evidence of the success of the gravel and sulfur amendments. The documented pulsing of soil ions in the soil from some depth to the surface was observed. Within the time of one year, it is not possible to ascertain at which point along that pulsing concentration the samples were taken, therefore, more monitoring is needed. Soil bacteria counts were indeterminate. Over time, a decrease in soil bacteria was observed from November (low temperature, high precipitation) to July (hot, dry, and saline conditions). This observation was possibly the result of dry soil conditions and high soil salinity. In summary, the desired increase in calcium concentrations in the soil was observed and a decrease in sodium, magnesium, sulfate, and chloride was observed. The differentiating the effect of the LCS installation and natural pulsing of soil ions back to the surface makes it difficult to determine the effectiveness of the LCS in the scope of one year. A longer monitoring period is needed to determine the benefits of the LCS installation at the Bartlesville, OK site.
10 TABLES AND FIGURES Figure 1. Panoramic View of Area 1- Looking Northwest Figure 2. Overall View of Bartlesville Site
11 Figure 3. Permeability of Area 1 Soils with Respect to Time Figure 4. Area 1 Background Permeability and Soil Ion Concentration Sampling Layout
12 Figure 5. Average Daily and Cumulative Rainfall for Bartlesville, OK Site from September 15 to November 18, 2000 Figure 6. Average Sodium Concentration of Soil in Area 1 Over Time
13 Figure 7. Average Calcium Concentration of Soil in Area 1 with Respect to Time Figure 8. Average Magnesium Concentrations in Area 1 Soil Over Time
14 Figure 9. Average Chloride Concentrations in Area 1 Soil Over Time Figure 10. Average Sulfate Concentrations in Area 1 Soil Over Time
15 Figure 11. Percent Reduction in Soil Ion Concentration in Area 1 from 7/20/99 to 7/10/01 (15) Figure 12. Average Bacterial Populations Count Comparison Between Amended and Non- Amended Cells in Area 1 on 11/18/00 and 7/10/01
16 Figure 13. Average Bacterial Populations Count Comparison between Amended and Non- Amended Cells in Area 1 on 11/18/00 Figure 14. Average Bacterial Populations Count Comparison Between Amended and Non- Amended Cells in Area 1 on 7/10/01
17 Figure 15. Average Bacterial Population Count Comparison Between Amended and Non- Amended Cells in Area 2 from 11/18/00 to 7/10/01 Figure 16. General Location of Oklahoma Mesonet Station #32 With Respect to Bartlesville, OK.
18 Figure 17 Precipitation and Temperature in Three Months Prior to July 2001 Sampling Figure 18. Average Daily Rainfall and Soil/Air Temperature for Bartlesville, OK Site from November 2000 to July 2001.
19 Figure 19. Daily Rainfall From Project Start-up on 9/15/00 to First Sampling Event on 9/24/00.
20 REFERENCES CITED 1. Johnson, G.V. Reclaiming Slick-Spots and Salty Soils, OSU Extension Facts No. 2226, Cooperative Extension Service, Division of Agriculture, Oklahoma State University (April, 1989). 2. Atalay, A., Pyle, T.A., and Lynch, R.A., Strategy for Restoration of Brine-Disturbed Land, in Journal of Soil Contamination, 8(3): (1999). 3. Weathers, M.L, Moore, Ford, D.L., and Curlee, C.K., Reclamation of Saltwater- Contaminated Soil in Big Lake Field, Trans. Gulf Coast Assoc. Geol. Soc., 44, 737, (1994) 4. Jones, J.L., Veenstra, J.N., Sherif, N.Y., and Painter, S.J., Remediation of Oilfield Brine Scars with Subsurface Drainage and a Solar Evaporation Pond, in Proceedings of the 7 th International Petroleum Environmental Conference, K. Sublette, Ed., November 7-10, 2000, Albuquerque, New Mexico. 5. American Society for Testing and Materials, Annual Book of ASTM Standards, Section 4: Construction, ASTM West Conshohocken, PA. (1997). 6. AA Methods book PerkinElmer Instruments, LLC, Analytical Methods for Atomic Absorption Spectrometry, Part Number , Release E, August, (2000). 7. Tate, R.L., Soil Microbiology, 48-54, New York, John Wiley and Sons, Inc. (1995). 8. Harris, T.M., Schulte, K., High, A., Yates, R., Sublette, K., and Tapp, B., Remediation of Brine-Impacted Soil with a Leachate Collection System, in Proceedings of the 5 th International Petroleum Environmental Conference, K. Sublette, Ed., October 20, 1998, Albuquerque, New Mexico. 9. De Jong, E. Reclamation of Soils Contaminated by Sodium Chloride in Can. J. of Soil Sci., 62, (May 1992). 10. T.M. Harris, Brine-Impacted Soils, Remediation, in Encyclopedia of Environmental Analysis and Remediation, 823, New York, John Wiley & Sons, (1998). 11. Atlas, R.M., Media for Environmental Microbiology, 462, Boca Raton, FL., CRC press, (1995). 12. Tate, R.L., Soil Microbiology, Ch 14 The Sulfur and Related Biogeochemical Cycles, Section 14.3 Biological Sulfur Oxidation, , New York, John Wiley and Sons, Inc. (1995). 13. Data downloaded from Oklahoma Mesonet Database, Copan Station #32,
21 14. Harris, T.M., Dewan, C., High, A., Tapp, B., and Sublette, K., Remediation of Brine-Impacted Soil with Subsurface Drainage: Year 2 of the Barnard No. 1 Project, in Proceedings of the 6 th International Petroleum Environmental Conference, K Sublette, Ed., November 18, 1999, Houston, Texas. 15. T.M. Harris, personal communication, October 2001.