Groundwater Quality Assessment and Remediation

Summary of Expertise

  • Sampling and Analysis Plans
  • Monitoring and Training
  • Remediation Design
  • Construction Management
  • Agency Liaison

Maybe it's a nearby water well that has become contaminated.  Maybe it's a regulatory agency with lots of questions.   Maybe you're considering a real estate transaction.  Whatever the reason, EarthFax can assist you with your groundwater quality assessment and remediation needs.   Our experience has covered areas of less than one acre and areas of several square miles, and has included the following:

DESIGN AND CONSTRUCTION OF AN EJECTOR PUMP SYSTEM FOR GROUNDWATER RECOVERY.  EarthFax designed an ejector pump system for recovery of hydrocarbon-impacted groundwater at a petroleum refinery tank farm. This system was designed to replace an existing fluids recovery system that used standard centrifugal submersible pumps with electric motors. Refinery personnel determined that the electric motors on the submersible pumps would not meet their interpretation of the National Electrical Code Class I Division I requirements for electric motors in a potentially explosive environment. EarthFax was contracted by the refinery to investigate alternative methods for recovering total subsurface fluids from the tank farm using methods compatible with Class I Division I requirements, design the new system, and supervise its construction. The ejector system accomplished this goal by taking advantage of a partial vacuum environment to remove total fluids from the subsurface without the use of electric motors, pumps, or moving parts. The ejector system utilizes a venturi to create a partial vacuum as water is passed under pressure through a jet eductor system. Groundwater is thereby drawn into the ejector on a continuous basis. We installed the ejector system in an existing groundwater intercept trench that measured approximately 2,000 linear feet and included a nine fluids recovery wells, thereby minimizing construction costs. Each of the nine existing wells was retrofitted with an ejector that was sized according to our performance requirements for maintaining constant recovery of groundwater in the tank field. A closed-loop pumping system was installed using a single above-ground centrifugal pressure pump to provide a constant vacuum to the ejectors. Electrical wiring and controls for this pump were installed in explosion-proof environments. Recovered fluids are conveyed through underground HDPE pipe to a surge tank that feeds water to the pressure pump and conveys surplus water to the industrial sewer system, where it is conveyed to an on-site waste water treatment plant. The ejector system is a safe, economical, and efficient alternative to submersible pumps with electric motors in potentially explosive environments. Because the ejector system operates with no moving parts, maintenance costs are significantly less than those incurred using conventional submersible pumping systems.

REMEDIATION OF GROUNDWATER THROUGH AIR SPARGING. A major delivery pipeline carrying gasoline from Utah to Washington was ruptured during a construction project which was underway to replace an older section of the pipeline. EarthFax provided emergency-response and long-term engineering and construction management services to remediate contamination associated with the release. Initial remediation measures implemented to control off-site contaminant migration included recovering 6,820 gallons of free phase product from the groundwater and excavating approximately 2,000 cubic yards of contaminated soil. Significant cost savings were achieved by recycling the excavated soil in a nearby asphalt plant and by transporting recovered liquids to a nearby refinery waste water treatment plant. Subsequent to these activities, an air sparge system was designed to remediate dissolved phase petroleum product in the groundwater. The design was based on the quantity of product spilled, the volatility and dissolution properties of the product, the soil type, and the direction and rate of groundwater flow. Eight sparge wells were installed and screened below groundwater. In order to maximize the efficiency of this technology, sparge wells were strategically placed downgradient from the zone of contamination and were spaced at a distance which would provide a curtain of air from groundwater elevation to the surface. Because the surface of the site was to be finished as a parking lot, vent wells were also installed to provide a pathway for sparged air to reach the ground surface. Additionally, well boxes and covers were designed to accommodate vehicle traffic in the parking lot. Monitor wells were installed to measure the efficiency of remediation activities. Operation and monitoring of the system is currently ongoing.

GROUNDWATER STATISTICAL ANALYSES. Statistical analyses are currently being performed on analytical data resulting from long-term monitoring of the upper aquifer beneath a RCRA closure cell. These analyses are performed in compliance with permit requirements, are implemented to detect the discharge of contaminants to groundwater from the closure cell, and are preceded by data validation to ensure that results of statistical analyses are accurate. Both intra-well and inter-well comparisons are performed. Intra-well comparisons check for trends (increasing or decreasing) in analyte concentrations within wells. Inter- well comparisons check whether downgradient wells have concentrations statistically different than upgradient wells and whether current concentrations are statistically different than baseline concentrations. These comparisons are made using the Mann-Kendall Trend Test and parametric analysis of variance (ANOVA). Comparisons using the latter method are particulary useful in determining the relative importance of differences between upgradient and downgradient concentrations or between current time and baseline concentrations.

REMEDIATION OF SOLVENT-CONTAMINATED GROUNDWATER. A recovery and treatment system was installed to remediate groundwater and soil contamination at two sites in Michigan, one formerly containing two leaking underground solvent storage tanks and one the site of former dumping of paint solvents. Soils in the vicinity of the former leaking tanks were also excavated and aerated to remove the source of continued contamination. Site data developed by other consultants were reviewed and additional assessments (including soil-gas and water-table surveys) were completed as necessary to more accurately define local contamination. Recovery wells, recovery trenches, and granular activated-carbon treatment systems were installed to treat the groundwater. The hydraulic effectiveness of the recovery systems was verified through local groundwater modeling. EarthFax also provided operational services for the treatment systems. Bio-fouling of a particulate filter was encountered at one location during initial pumping from the recovery well. As a result, a program consisting of periodic hot-water injection was designed to eliminate this problem. A vapor-extraction system was installed at one of the sites to further remediate residual contamination in vadose-zone soils. Total soil-vapor concentrations declined from 700,000 ppb to less than 1 ppb after 6 months of system operation. The vapor extraction system was then converted to a biosparging system to further reduce concentrations in the groundwater and vadose zones.

REMEDIATION OF CONTAMINATED GROUNDWATER THROUGH AIR STRIPPING. Unusually high levels of petroleum contamination were discovered by EarthFax during the course of long-term groundwater monitoring at a petroleum refinery tank field. This discovery prompted an investigation using soil gas monitoring, installation and sampling of piezometers, and installation of test pits to discover potential sources of contamination. Results of the investigation led to the  property of an adjacent petroleum products pump station which is owned by a sibling company of the refinery. Through cooperative agreements between the refinery and the pump station, the investigation was advanced onto the pump station property. By speciating samples of petroleum product found during the investigation, EarthFax was able to verify that a previously unidentified source of contamination was originating from the pump station and had begun to migrate into the refinery tank field. This contamination contained the gasoline additive MTBE which was a key discovery in verifying that the contamination originated from the pump station property rather than from the refinery. A groundwater intercept trench was installed, from which the product and contaminated water are pumped into an oil/water separator to recover free-phase product. The dissolved-phase liquids are then passed through a tray-style air stripper to remove volatile organic compounds. Permission was granted by the appropriate regulatory authority to discharge treated groundwater to a nearby POTW line for disposal. Additionally, a deminimus air permit was granted for emission of volatile organic compounds during treatment. EarthFax was able to use a tray-style air stripper already owned by the client, resulting in a significant reduction to the cost of the project.
GROUNDWATER ASSESSMENTS AND CLOSURE PLAN DESIGNS AT A PETROLEUM REFINERY. Groundwater-quality assessments were conducted adjacent to waste-water treatment ponds and a product loading rack at a petroleum refinery in eastern Utah to aid in the development of closure and remedial-action plans for the sites. Several shallow piezometers were installed to determine the direction of groundwater movement near the ponds. Based on this information, monitoring wells were designed, installed, and sampled. Field tests were performed to determine the hydraulic characteristics of the shallow aquifer. Soil samples were also collected in the vicinity of the loading rack to assist in developing remedial-action plans for the contaminated soil. Groundwater-quality and soil-contamination assessment reports were prepared and served as the basis for closure of the waste-water treatment ponds and remediation of leakage from the product loading rack. Under the closure plan for the waste-water treatment ponds, the sludges were chemically stabilized (using cement-kiln dust) and disposed of in an on-site closure cell. Under the remedial-action plan for the loading rack area, a groundwater recovery trench was installed, groundwater and free-phase hydrocarbons were removed, contaminated groundwater was treated in the facility waste-water treatment system, free-phase hydrocarbons were either shipped off site or re-processed through the refinery, and contaminated soils were treated through aeration and bioremediation.

GROUNDWATER-QUALITY ASSESSMENT AND REMEDIATION AT A REFINERY TANK FARM. A groundwater-quality assessment was performed at a refinery tank farm in Utah used to store both crude and refined petroleum. A soil-gas survey and a shallow water-table survey (using piezometers) were performed to assess the general direction of groundwater flow and the probable extent of contamination. Based on these data, several monitoring wells were installed, tested, and sampled to better quantify the extent and magnitude of contamination and the probable rates of groundwater movement. A report was then prepared presenting the results of the assessment work. A remedial-action plan was designed to recover and treat the contaminated groundwater. This plan included installation of groundwater and free-phase hydrocarbon recovery trenches, treatment of the contaminated groundwater in the refinery waste-water treatment system, and re-processing of the free-phase hydrocarbons through the refinery. Plans were also developed to reduce the potential for future contamination of the site resulting from spills and leaks through the installation of soil cement within the tank farm area. Monitoring of the installed recovery systems confirmed the capture of all hydrocarbons within the zone of influence established by the system.

GROUNDWATER-QUALITY ASSESSMENT AT A DISTRIBUTION-FACILITY TANK FARM. A groundwater-quality assessment was performed at an above-ground storage tank farms in Nevada for major a petroleum refiner. Several monitoring wells were installed, tested, and sampled to determine the extent and magnitude of contamination as well as the probable rates of groundwater movement. A detailed assessment report was then prepared.

. A remedial investigation of groundwater contamination is presently being performed at a major petroleum refinery in Michigan. Previous investigations identified several areas of groundwater contamination resulting from past leaks and spills. Most areas of contamination contained free-phase hydrocarbons at the water table. The investigation is designed to delineate the extent and magnitude of groundwater contamination and evaluate hydrogeologic conditions, which will form the basis of a remedial action plan. Investigations are being performed both on site and off site. Interim corrective measures include the installation of several large-diameter wells to recovery free-phase hydrocarbons and contaminated groundwater.

GROUNDWATER-QUALITY ASSESSMENTS IN THE VICINITY OF LEAKING UNDERGROUND GASOLINE STORAGE TANKS. Groundwater-quality assessments were performed to detect the extent, magnitude, and source of groundwater contamination resulting from leaking underground petroleum storage tanks at locations in Utah and Michigan. Soil-gas surveys have been performed to determine the approximate extent of contamination, several piezometers have been installed to assess the shape of the potentiometric surface, monitoring wells were installed, soil and groundwater samples have been collected, and data have been interpreted. Based on the interpretation, the extent of contamination was delineated and quantities of free-phase, adsorbed, and dissolved contaminants were estimated. At selected sites, remediation programs were designed to recover free-phase hydrocarbons from the area and remediate the dissolved and adsorbed portions. Technical liaison was provided between the owners, legal counsel, the insurance companies, and regulatory agencies. Expert witness testimony was provided for legal proceedings as required.

REMEDIATION OF PETROLEUM-CONTAMINATED GROUNDWATER. A recovery and treatment system was designed and installed at the site of a leaking underground petroleum storage tank in Michigan. Wells and a trench were used to recovery groundwater. The contaminated groundwater was treated using granular activated carbon. Due to the natural presence of sulfur-reducing bacteria in the groundwater, a pre-treatment system was designed to prevent biofouling of the carbon treatment units. Documentation was prepared to obtain water and air discharge permits that were required by the regulatory agencies prior to operation of the treatment system. Operation of the treatment system is ongoing.

GROUNDWATER ASSESSMENT AND REMEDIATION AT A PRINTED CIRCUIT FACILITY. Eight monitoring wells were installed adjacent to a printed circuit facility in Utah to determine the magnitude of groundwater contamination resulting from leaking organic solvents. The extent of contamination had been previously determined using a soil-gas survey. Health and safety plans were prepared, wells were installed, water-quality samples were collected, and the data were interpreted. Based on this investigation, a remedial-action plan was designed consisting of pumped subsurface drains to intercept the shallow contaminated groundwater. During initial operation of the groundwater recovery system, the hydraulic effectiveness of the system was tested to ensure capture of the contaminants.

SURFACE AND GROUNDWATER QUALITY ASSESSMENTS OF A MAJOR INDUSTRIAL FACILITY. Surface and groundwater quality assessments were developed and implemented at the site of a major propellant and rocket-motor manufacturing facility in northern Utah. Contaminants of concern at the facility included explosives, organic solvents, and heavy metals. Health and safety plans were developed to protect drillers and engineers during monitoring well installation. Over 90 monitoring wells, deep piezometers, and observation wells were installed under tight time schedules to meet regulatory constraints. Aquifer characteristics tests were performed to determine the rate and direction of groundwater movement. Surface and down-hole geophysical investigations were performed to aid in defining local stratigraphic conditions. Detailed numerical modeling investigations were performed to determine the effectiveness of proposed remedial-action alternatives. In addition, approximately 20 surface-water sampling stations were installed for the collection of water-quality data. Water-quality samples were collected on a quarterly basis from each monitor well and surface-water station. Specific tasks completed for the project included:

  • Performance of groundwater quality and hydrogeologic characterizations of the site and adjacent areas;
  • Assessments of the extent and magnitude of off-site contamination;
  • Numerical modeling of the groundwater flow system to determine the hydraulic effectiveness of remediation;
  • Analysis and ranking of off-site wells for contamination potential;
  • Preparation of QA/QC plans for collection of water samples and the installation of monitoring wells;
  • Development of health and safety plans for drilling and sampling;
  • Design of a solid-waste landfill for on-site disposal of non-hazardous solid waste generated at the site;
  • Performance of a floodplain encroachment investigation;
  • Determination of the effectiveness of monitoring well purging during sampling;
    Preparation of drilling specifications;
  • Performance of groundwater, surface water, and soil assessments at an open-burning disposal facility; and
  • Preparation of portions of the facility Part B Permit related to surface and groundwater conditions at the site.

CONTROL OF GROUNDWATER CONTAMINATION AT AN ACTIVE URANIUM MILL. An investigation was conducted at the site of an active uranium mill in southeastern Utah to determine appropriate remedial actions to prevent future groundwater contamination after a plume had developed due to seepage from tailings ponds. Surface geophysical investigations (electrical resistivity and very-low-frequency electromagnetic) were conducted to determine the extent of contamination, bedrock lithology, and the location of major groundwater-conducting fractures. Water-level and -quality data were utilized from over 140 previously existing and new monitor wells to aid in defining the extent of groundwater contamination. Long-term pumping tests were conducted to determine the anisotropic nature of the groundwater hydraulic system. The fractured aquifer was modeled to determine the rate of contaminant migration and the effectiveness of the proposed remedial action. An interim remedial-action plan was then designed and implemented. This interim plan was then supplemented following collection of additional data. The remedial-action plan consisted of hydrodynamic control of contaminant migration through the operation of several groundwater recovery wells. The contaminated groundwater was pumped to evaporation ponds for disposal.

GROUNDWATER QUALITY INVESTIGATIONS AT AN ABANDONED SMELTER. Groundwater, surface water, and soil investigations were conducted at the site of an abandoned copper/lead smelter in Utah to determine the extent of contamination at the site. The site, which was being considered at the time for addition to the National Priorities List (Superfund), was proposed for development by the client as a business park. Thirteen monitoring wells were installed and field tests were conducted to determine the rate and direction of groundwater movement beneath the site. Water-quality samples were collected from the on-site monitor wells and off-site private and municipal wells to determine the extent and magnitude of groundwater contamination. Data received from the laboratories were interpreted using geochemical and hydrologic models to determine the need for future remedial actions. A conceptual remedial-action plan was developed, together with work plans for remedial design. Information was also provided in support of the client's pursuit of Innocent Purchaser Defense rules. The site was subsequently added to the National Priorities List, following which the U.S. Environmental Protection Agency contracted directly with another consultant for additional assessment and design services. EarthFax continued to provide reviews of EPA-contracted documents on behalf of the client, providing recommendations for alternative characterization and remediation strategies.

GROUNDWATER MONITORING AT A U.S. AIR FORCE BASE. Water quality samples were collected for an Air Force base in northern Utah at two of eight operable units from June 1998 through June 1999. At one of the operable units 67 wells, 3 springs, 4 domestic wells, and one storm-water outfall were sampled on a quarterly basis (or more frequently) in connection with long-term monitoring requirements, site remediation activities, or rain events. At the other operable unit 37 groundwater wells, collection sumps, springs, and domestic wells were sampled on a quarterly basis in connection with long-term monitoring requirements and site remediation activities. Well completion depths at the two operable units ranged from 20 feet to 110 feet. Sampling of groundwater wells was accomplished using dedicated bladder pump systems. Field activities were implemented according to strict groundwater sampling and analysis plans. Additionally, site-specific health and safety plans were developed and implemented by EarthFax prior to beginning field work at the sites. Analysis of water samples collected at these sites was conducted for a wide array of organic and inorganic compounds. Data from these analyses were used to monitor levels of contamination in underlying aquifers which are known to be contaminated with chlorinated and inorganic compounds. During one of the sampling events, a field audit of groundwater sampling activities was conducted by Air Force personnel. In a memorandum which summarized the field audit, EarthFax personnel were commended for their proficiency, professionalism, degree of knowledge regarding sampling methodologies and techniques, and for their recommendations on how to improve the quality and reduce costs of field work. One cost reducing suggestion made by EarthFax which was implemented at the sites was the use of micropurging technology at selected groundwater monitoring wells. This resulted in a significant savings to the client both in terms of the time required to collect representative groundwater samples and in terms of the volume of purge water which required disposal at the base industrial waste-water treatment plant.

REDUCING LONG-TERM GROUNDWATER MONITORING COSTS AT A PETROLEUM REFINERY.  EarthFax has performed long-term monitoring of groundwater and surface water at a petroleum refinery since 1991 using a rigorous sampling plan we wrote to ensure that analytical results accurately represent groundwater conditions.  The sampling plan requires collection of QA/QC samples and detailed documentation of sample collection and handling procedures.  Sampling activities are performed by EarthFax personnel in accordance with a site-specific health and safety plan that complies with refinery safety procedures.  Following each compliance sampling event, we develop a report that summarizes field activities, reviews analytical results relative to established background constituent levels, and makes recommendations. Each report includes groundwater surface elevations, a potentiometric surface map, copies of analytical reports, tabularized summaries of analytical data, and a discussion of QA/QC data.  EarthFax compiles analytical data in a relational database that is used to identify changes and trends in groundwater conditions at the site. Originally, a total of 44 groundwater wells ranging from 12-105 feet deep were sampled quarterly for a wide range of organic and inorganic constituents in compliance with a Consent Order issued by the State of Utah.  In 1997, a Post-Closure Permit was issued to the refinery in response to an aggressive program undertaken to successfully characterize and remediate numerous Solid Waste Management Units.  The issuance of a Post-Closure Permit allowed EarthFax to assist the client in successfully petitioning the State for a reduction in the number of compliance monitor wells that are sampled (from 44 to 20), the frequency of sampling campaigns, and the number of groundwater constituents that are analyzed in the samples collected from each well.  These reductions were based on the current and historic use of the facility, its current regulatory status, and the information provided in the relational database.  In the most recent revision to the Post-Closure Permit, EarthFax prepared a Quality Assurance Project Plan that proposed sampling compliance wells using disposable point source flexible membrane samplers (e.g. HydraSleeve™) instead of traditional bladder pumps.  The new samplers are less expensive than bladder pumps, are maintenance free, require no well purging activities prior to collecting groundwater samples, and provide analytical results that are equal in accuracy to samples collected using bladder pumps.  These changes were approved by the regulatory agency and have resulted in significant savings to the client.

GROUNDWATER MONITORING AT TWO RADIOACTIVE-WASTE DISPOSAL CELLS. Groundwater monitoring was conducted in 1996 at two radioactive-waste disposal cells located in Utah's west desert. These cells are regulated and permitted by the U.S. Nuclear Regulatory Commission, grantor of a Materials License to handle nuclear material, and the Utah Department of Environmental Quality, grantor of a Groundwater Quality Discharge Permit for Low-Activity Radioactive Waste. Monitoring was conducted in strict compliance with an approved groundwater monitoring quality assurance plan. This plan was implemented in keeping with the intent of the Materials License and the Groundwater Quality Discharge Permit. A total of 12 groundwater wells at one of the cells were sampled on a quarterly basis, and 9 wells were sampled at the other cell on a semi-annual basis. These wells were designed to monitor the upper aquifer underlying the disposal cells for a wide array of organic, inorganic, and radiologic compounds. Well depths were generally in the 20- to 30-foot range. The primary method used for collection of groundwater samples was dedicated bladder pumps. A site specific health and safety plan was followed by EarthFax personnel during execution of field work at the site. Field monitoring activities included depth-to-groundwater measurements, measurement of specific physical parameters to determine when purged groundwater accurately represented formation groundwater, sample collection, collection of an appropriate number of QA/QC samples, and appropriate sample documentation and handling. EarthFax provided reports to the client which discussed field activities, analytical results, data validation and quality assurance, site hydrology, and conclusions and recommendations. Pertinent information presented in these reports included a site map, surface elevations of groundwater, freshwater equivalent head calculations, the potentiometric surface of groundwater at the time of the sampling event, anion/cation balance calculations, validation that the required holding times were met, field log forms, tabularized summaries of analytical results, analytical reports, copies of sample bottle certificates, suction lysimetry field notes and analytical results for pore water samples collected in the field, laboratory quality control data, and Relative Percent Difference analysis of field duplicates.


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7324 South Union Park Ave., Midvale, Utah 84047 | Phone: 801-561-1555

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