JBR Environmental Consultants, Inc. has direct-push systems which service clients company-wide. The Geoprobe Model 540U is mounted on a four-wheel drive, one-ton pickup truck. This unit produces 18,000 lbs of down force and 25,000 lbs of retraction force. The other Geoprobe utilizes a Geoprobe GH40 Hammer mounted in a four-wheel drive van that is also equipped with an onboard mobile laboratory.
The van is a state-of-the-art subsurface investigation system capable of advancing up to 20 subsurface probes per working day. This discreet system consists of a hydraulic, direct-push, soil probing unit located at the rear end of the van, with a fully-contained, climate-controlled, on-board laboratory in the middle section of the van. The laboratory consists of a laboratory grade gas chromatograph (GC), a digital integrator, an on-board computer, a printer, and associated laboratory equipment. The GC is equipped with the following three detectors:
The Geoprobe system can be used to perform subsurface soil, water or vapor surveys. It is capable of obtaining and analyzing soil samples, obtaining and analyzing groundwater samples, installing small diameter monitoring wells, pre-packed monitoring wells, piezometers, sparging implants, and injecting Oxygen Release Compounds (ORC). A staff of two to four operate the Geoprobe and direct the investigation.
Advantages of direct-push sampling capabilities include:
The availability of on-site analytical data results in cost savings over the conventional approach (sample, ship to the lab, and analyze) because:
Soil-Gas Survey - The Geoprobe system can be used to collect soil-gas samples through disposable post-run tubing, which runs from the tip of the probing unit to a purging pump located in the rear of the Geoprobe van. The gas samples are drawn from a sampling port using a gas-tight syringe. The gas sample is directly injected into the GC by the operator. The on-board computer PeakSimple software collects the data and produces a chromatogram. The PeakSimpleTM software integrates the chromatogram and computes the gas component concentrations, utilizing data from a calibration standard. The results are printed within minutes and are available for review by the operator. The chromatograms are saved on the computer memory so that they can be summarized at the end of the project.
This quick availability of analytical results allows on-site personnel to pin-point contamination sources and position subsequent probe points to clearly determine the horizontal and vertical extent of the contamination. This method of investigation has the following advantages over conventional methods:
The precision of the on-board laboratory, coupled with the system's ability to advance numerous probes each day, can result in a large amount of data being collected and interpreted each day. As much as a twenty-fold increase in data collection can be realized over conventional drilling and sampling methods. The system is cost effective, discreet, and reliable.
Soil Sampling- Soil samples can be collected using several different-sized sampling devices. JBR is equipped with Geoprobe’s Large Bore and Macro-Core Closed-Piston Soil Sampling equipment. The type of soil sampling equipment utilized on a project will depend on the amount of soil sample required, soil conditions at the project site and the objective of the project. Soil samples can be collected in clear plastic (PVC), teflon (PTFE), brass, and stainless steel liners, depending on project requirements. These liners can easily be capped and sent to a laboratory for analysis.
Groundwater Sampling- Groundwater samples can be collected utilizing Screen Points, Mill-Slotted Well Points, Tubing and Check Valves, Mini Bailers, and Screen Implants. The method to be chosen for groundwater collection depends on the aquifer characteristics, sample contaminants and the objectives of the project. JBR is equipped to provide any of the above groundwater sampling methods. Where depth to groundwater is less than 35 feet, a peristaltic pump may also be utilized to extract groundwater.
After obtaining groundwater samples, the on-board GC can be used to analyze the water samples in the field. The water samples are placed in a 40-ml vial and are then equilibrated in a temperature-controlled incubator. The GC operator then obtains a vapor sample through the septum in the vial and injects it into the GC. The data collection and interpretation is similar to that of the soil-gas survey, with the exception that a water-borne calibration standard is used.
Small Diameter Monitoring Wells
JBR has the ability to install small diameter monitoring wells. The Geoprobe’s 2.125-inch probe rods can install a small diameter well with a pre-packed screen system or a standard well completion without pre-packed screen. The type of well completion will depend on the soil characteristics and the objective of the project.
Advantages of Small Diameter Monitoring Wells
Smaller subsurface disturbance. Smaller subsurface disturbance reduces the area for surface water to enter the borehole, which is the main purpose of the bentonite seal.
Reduced Installation Costs and Time. Installation of small diameter wells cost approximately 1/3 of the cost of a 2-inch monitoring well. Well materials are less expensive and installation can be completed in 1-2 hours. Reduced installation expense allows additional investigation points, therefore increasing confidence in identifying the extent and magnitude of groundwater contamination.
Reduced Sampling Costs and Time. Sampling procedures require the removal of three well volumes prior to sampling. Small diameter wells have smaller well volume, thereby reducing sample time and project costs.
Minimal Waste Generation. Direct-push sampling creates little or no drill cuttings, reducing the problem and expense of drill cuttings disposal.
Piezometer/Sparger Implants. JBR has the ability to install 3/4-inch PVC or steel piezometers using the Geoprobe system. The type and size of piezometer to be installed depends on the soil characteristics and the objective of the project. Piezometers can be used to determine groundwater flow direction, and to monitor contaminant migration. JBR can also install sparger implants for in-situ gas sparging systems.
Injection of Remedial Compounds (ORC). We have the ability, experience and expertise required to inject oxygen release compound ORC as part of the remediation of a site. JBR utilizes Geoprobe rod accessories and grout pump (GS-1000) to inject ORC at desired depths and intervals. JBR also utilizes a DP800 high volume/medium pressure pump and integrated mixing system to inject potassium and sodium permanganate. JBR is capable of “bottom up” or “top down” injections.
The volume, depth and interval of injection is dependent on the soil and groundwater characteristics, contaminant types, and the remediation goals for the project.
Mobile Lab Services
Often used with our Geoprobe services, our on-board laboratory is fully contained and climate controlled. It contains a laboratory grade gas chromatograph, a digital integrator, a computer, a printer and associated laboratory equipment. The gas chromatograph is equipped with a photoionization detector (for aromatic hydrocarbons), a flame ionization detector (for general organic hydrocarbons) and an electron capture detector (for halogenated compounds).
The availability of on-site analytical data results in cost savings over the conventional approach of shipping to an off-site lab and waiting for results before taking the next step. Contaminant plume mapping can be performed immediately because field lab results help in locating subsequent probe points. The immediate results allow quick and accurate definition of the horizontal and vertical extent of contamination with less sampling.
Our mobile lab can handle field analyses for various contaminants including the following:
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PCE Contamination Remediation Using Sodium Permanganate
JBR assisted in this PCE contamination remediation project by using a sodium permanganate injection system.
Delineation of a Fuel Oil Spill From a Tank Overfill
JBR personnel performed Geoprobe® soil boring and on-site analytical services for a fuel spill in Yellowstone National Park, Wyoming.
Abandonment of Monitoring Wells via Pressure Grouting
JBR performed Geoprobe® injection pump services at three groundwater monitoring wells in Yellowstone National Park, Wyoming.
Delineation of Pesticide Contamination at Grain Elevators
JBR Personnel provided Geoprobe® soil and groundwater borings, small diameter well installations, and on-site analytical services at 4 grain elevators in Central Montana.
Delineation of Hydrocarbon Contamination at Auto Dealership
JBR performed Geoprobe® soil borings and sample collection at a former auto dealership in Bozeman, Montana.