By John Fontana, CPG, CWD
Direct Push Technology (DPT) has become one of the most important tools in modern environmental site investigation and remediation. Developed specifically for environmental applications, DPT provides a faster, more efficient, and often less expensive alternative to conventional drilling methods for collecting soil, groundwater, and soil gas data.
The technology emerged in the late 1980s and early 1990s as environmental professionals sought better ways to characterize contamination without the cost, waste generation, and logistical challenges associated with traditional hollow-stem auger and rotary drilling methods. Over the past three decades, DPT has evolved from a simple sampling platform into a highly sophisticated system capable of collecting continuous environmental data, supporting advanced site characterization, and implementing in-situ remediation injection technologies.
The Evolution of Direct Push Technology
The earliest applications of DPT focused on environmental sampling. Specialized hydraulic rigs were designed to advance small-diameter tools into the subsurface without generating drill cuttings. This approach enabled rapid collection of soil samples, groundwater samples, and soil gas data while minimizing investigation-derived waste and reducing site disturbance.
As the technology matured, new tools were developed to improve both data quality and efficiency. Today, DPT systems support:
- Continuous and discrete soil core sampling
- Discrete groundwater sampling at specific depth intervals
- Soil gas and vapor intrusion investigations
- Hydraulic conductivity and formation testing
- High-resolution site characterization (HRSC)
- In-situ remediation injections
Improving Data Quality Through Better Sampling
One of the most significant advancements in DPT has been the development of dual-tube coring systems. Unlike conventional drilling methods that may disturb or mix soils during drilling, dual-tube systems allow collection of relatively undisturbed continuous cores while the outer casing stabilizes the borehole and prevents cross-contamination.
These systems provide:
- Continuous lithologic information
- Improved identification of thin contaminant zones
- Better understanding of site geology and hydrogeology
- Reduced cross-contamination between intervals
For groundwater investigations, discrete interval groundwater sampling tools allow environmental professionals to collect samples from specific depths without installing a monitoring well. This approach often provides higher-resolution vertical data, helping identify contaminant distributions that may otherwise be missed using conventional well-screened intervals.
Similarly, specialized soil gas sampling tools have transformed vapor intrusion and vadose zone investigations by allowing rapid collection of soil gas samples at targeted depths. These data can help define contaminant migration pathways and identify potential risks to buildings and occupants.
Supporting High-Resolution Site Characterization
As environmental professionals recognized the value of collecting more detailed subsurface data, DPT became the platform of choice for High-Resolution Site Characterization (HRSC).
Advanced direct sensing tools such as Membrane Interface Probe (MIP), Optical Image Profiler (OIP), Hydraulic Profiling Tool (HPT), Electrical Conductivity (EC), and Laser-Induced Fluorescence (LIF) sensors can now be deployed through DPT platforms to generate continuous subsurface datasets in real time.
These technologies help create more accurate conceptual site models, improve remediation design, and reduce uncertainty in site decision-making.
Expanding into In-Situ Remediation
Today, DPT is used not only to characterize contamination but also to treat it. Specialized injection tooling allows practitioners to deliver remedial amendments directly into targeted treatment zones. Applications include enhanced bioremediation, chemical oxidation, chemical reduction, sorptive amendments, and emerging treatment technologies.
By combining characterization and treatment capabilities on a single platform, DPT has become a cornerstone technology for modern environmental remediation projects.
Looking Ahead
Direct Push Technology continues to evolve as new sensors, characterization methods, and remediation approaches are developed. What began as a faster way to collect environmental samples has become an integrated platform for site investigation, conceptual site model development, and in-situ treatment implementation.
In future articles, we will take a deeper dive into High-Resolution Site Characterization (HRSC) tools, direct sensing technologies, and the growing role of DPT in modern remedial injection programs.